Application note 3148
Effective September 2015
Supersedes July 2015
BUSSMANN
SERIES
Quik-Spec Coordination Panelboard (QSCP)
Contents
DescriptionPage
DescriptionPage
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Features/benefits. . . . . . . . . . . . . . . . . . . . . . . . . . 2
QSCP Overview . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Selective coordination made easy. . . . . . . . . . . . . 5
Comparing fusible branch circuit panelboards . . . 6
QSCP Short-Circuit Current Ratings (SCCRs). . . 7-8
How to achieve selective coordination. . . . . . . 9-10
Selective coordination using fuses . . . . . . . . . . . 11
Selective coordination using upstream Eaton
thermal magnetic circuit breakers. . . . . . . . . . . . 12
240, 480, 600Vac Quick Pick tables . . . . . . . . 13
240Vac Circuit breaker tables. . . . . . . . . . . . . 14
480Vac Circuit breaker tables. . . . . . . . . . . . . 15
600Vac Circuit breaker tables. . . . . . . . . . . . . 16
QSCP applications and fuse sizing
Lighting circuits. . . . . . . . . . . . . . . . . . . . . . . .
Motor circuits . . . . . . . . . . . . . . . . . . . . . . . . .
Transformers. . . . . . . . . . . . . . . . . . . . . . . . . .
CUBEFuse sizing for motors (115-575Vac). . .
Protecting leads fed from Uninterruptable
Power Supplies (UPS) . . . . . . . . . . . . . . . . . . . .
Surge Protective Devices (SPDs) . . . . . . . . . . . .
Reference materials . . . . . . . . . . . . . . . . . . . . . .
17
18
19
20
21
22
23
Quik-Spec Coordination Panelboard (QSCP)
application note
Application Note 3148
Effective September 2015
Introduction
The Bussmann® series Quik-Spec™ Coordination Panelboard (QSCP)
is innovative in many ways compared to other commercially available
branch circuit panelboards, while providing the benefits of currentlimiting fusible overcurrent protection. The QSCP can simplify the
effort to ensure Code compliance for systems where selective
coordination is a mandatory NEC® requirement, as well as for other
electrical systems.
Issue
By utilizing the Bussmann series CUBEFuse™ Compact Circuit
Protector Base (CCPB) fusible disconnect, the panel is rated up
to 600Vac and is capable of providing up to a 200kA short-circuit
current rating (SCCR). At the same time, it provides many features
that increase electrical safety.
Features
Benefits
Selective coordination between branch and upstream fuses or
upstream Eaton circuit breakers using published tables
Simplified selective coordination designs for fault levels up to
200kA, including systems required by NEC® 620.62, 700.28,
701.27, 708.54 and 645.27
to comply with electrical system protection requirements
UL Listed panel short-circuit current ratings available up to 200kA Easier
in NEC® 110.10
UL Listed, high, 300kA AC interrupting rating Low-Peak fuses
Code
compliance
Safety
Ease and
flexibility
Easily complies with the interrupting rating requirements of
NEC® 110.9
No need to be constrained by series ratings
CCPB branch circuit fused disconnect
Current-limiting overcurrent protection integrated with innovative,
compact, UL 98, horsepower rated, load-break branch circuit
disconnect
U.B.C. & C.B.C. Seismic Qualified, I.B.C. Approved (Uniform
Building Code, California Building Code, International Building
Code)
Meets the requirements of installation in areas subject to
earthquakes
Surge Protective Device option
Helps comply with 2014 NEC® 700.8 that requires a listed SPD
to be installed in or on all emergency system switchboards and
panelboards and 517.26 for healthcare life safety branch
CUBEFuse/CCPB amp rating rejection system
Helps ensure continued circuit protection at the specified
standard branch circuit amp rating
Finger-safe CUBEFuse and disconnect assembly
(with dead-front cover installed)
Helps prevent exposure to live components
Permanent lockout/tagout provisions on main and branch circuit
disconnects
Allows for isolation of individual branch circuit loads or entire
panel for safe work practices
CUBEFuse and CCPB disconnect interlocked
Helps ensure circuit is de-energized before fuse removal
Service fuses without removing deadfronts or interior trim
Reduced exposure to live electrical parts
UL Listed with up to 600Vac panel voltage rating
Suitable for use on most AC systems, 600V or less
UL Listed 125Vdc panel voltage rating on MLO with 20kA SCCR
with CCPB 80 amps or less.
Suitable for use on systems, 125Vdc or less and 80A or less
branch circuits
Standard 20 inch panel width
Space requirements equivalent to other commercially available
circuit breaker branch circuit panelboards
Non-fused main disconnect, fused main disconnect or main lug
only configurations available up to 400A
Provides design and overcurrent protection options
Local open fuse indication
Open circuits can be identified quickly and easily
CCPB branch circuit fused disconnect
Panelboard branch circuits configurable up to 100A in 1-, 2- and
3-pole devices with Class CF CUBEFuse overcurrent protection
(Class J, time-delay or fast-acting performance)
Surface and flush mount enclosures
18, 30 and 42 branch circuit positions
NEMA 1 and 3R enclosures
Door-in-door available
Installation design options
UL service entrance rated panel option
Sub-feed lug options
Sub-feed fused disconnect switch option
Equipped with six space spare CUBEFuse holder
2
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Spare CUBEFuses are readily available when in place, speeding
maintenance procedures
Quik-Spec Coordination Panelboard (QSCP)
application note
•
Effective September 2015
200A and 400A main disconnect
QSCP Overview
•
Application Note 3148
Ease of selective
coordination with upstream
Bussmann fuses or Eaton
circuit breakers
Panel SCCR available up to:
200kA for 600Vac or less
panels, 20kA for 125Vdc or
less panels.
•
Fused and non-fused versions
•
Fused disconnects use time-delay or fastacting Class J fuses
•
Allows for isolation of all branch circuits
•
Permanent lockout means
•
Contact blades visible without removing
dead-front cover
•
Interlock with dead-front cover ensures
switch is OFF before removing cover
•
600Vac or less
•
125Vdc, MLO only, CCPB
80A or less.
•
30A, 60A, 100A, 200A or
400A panel rating
•
Standard 20” width
•
18, 30 and 42 branch
positions available
•
Sub-feed lug options
•
Sub-feed fused disconnect
option
•
Surge Protective Device
option
•
Equipped with 6 space
spare CUBEFuse holder
•
Uses time-delay or fast-acting Class CF
CUBEFuse with Class J performance
•
Surface or flush mount
•
•
Door-in-door trim available
CCPB SCCR:
• 200kA/600Vac
30A, 60A and 100A CCP fused main
disconnect
•
Integrates fuse protection and disconnect
into single, finger-safe device
•
Time-delay or fast-acting Class CF
CUBEFuse with Class J performance
•
Switch interlock prevents removing fuses
while energized
•
Local open fuse indication
CCPB fused branch disconnect
•
20kA/125Vdc, 80A or less
•
Hp rated, branch circuit disconnect
•
Circuits up through 100A, 1-, 2- and
3-pole
•
Permanent lockout provisions
•
Local open fuse indication
•
Switch interlock prevents removing fuses
while energized
•
Fuse ampacity rating rejection
Main Lug Only (MLO)
Fused main disconnect
QSCP with time-delay
CUBEFuses for branch circuit
protection of all types of loads
QSCP with fast-acting
CUBEFuses for branch circuit
protection of electrical loads such
as those fed from a UPS
www.bussmann.com
3
Quik-Spec Coordination Panelboard (QSCP)
application note
Application Note 3148
Effective September 2015
Innovative time-delay or fast-acting Class CF CUBEFuse contact
blade design in conjunction with CCPB fused disconnect provides
amp rating rejection at specified levels (15, 20, 30, 40, 50, 60, 70,
90 and 100A - See Table 3). Blade design also interlocks with CCPB
disconnect assembly to prevent fuse removal while energized
Permanently installed
integrated lockout/
tagout provisions
CCPB disconnect handle provides clear
circuit status indication with colored and
international symbol markings
Local, neon open fuse indication
(requires panelboard bus be energized,
circuit closed and minimum 90Vac)
Time-delay or fast-acting Class CF
CUBEFuse provides Class J overcurrent
protection
Bolt-on style bus
connector
Table 1. CCPB specifications
Typical installed amp range
CCPB* part
number
Poles
CCPB-1-15CF
1
CCPB-2-15CF
2
CCPB-3-15CF
3
CCPB-1-20CF
1
CCPB-2-20CF
2
CCPB-3-20CF
3
CCPB-1-30CF
1
CCPB-2-30CF
2
CCPB-3-30CF
3
CCPB-1-40CF
1
CCPB-2-40CF
2
CCPB-3-40CF
Fuse
amp
range
1-15
1-20
1-30
Max
CCPB
amps
Time-delay
non-indicating
fuses
Time-delay
indicating
fuses**
Fast-acting
non-indicating
fuses
15
TCF1RN,
TCF3RN,
TCF6RN,
TCF10RN,
TCF15RN
TCF6,
TCF10,
TCF15
FCF1RN,
FCF3RN,
FCF6RN,
FCF10RN,
FCF15RN
20
30
TCF17-½RN,
TCF20RN
TCF25RN,
TCF30RN
TCF17-½,
TCF20
TCF25,
TCF30
FCF20
FCF25RN,
FCF30RN
Yellow label time-delay and blue label fast-acting CUBEFuse.
Time-delay CUBEFuse has optional open fuse indication to provide
positive fuse status at a glance. The fast-acting (blue label) version is
non-indicating only.
Table 2. CCPB horsepower ratings
CCPB disconnect
Hp rating @ Vac
Amp
rating
120
240*
240**
480
600
7.5
CCPB-(Poles)-15CF
15
0.5
1.5
3
5
CCPB-(Poles)-20CF
20
0.75
2
3
7.5
10
CCPB-(Poles)-30CF
30
1.5
3
5
15
10
CCPB-(Poles)-40CF
40
2
3
7.5
20
10
CCPB-(Poles)-50CF
50
3
5
7.5
20
10
CCPB-(Poles)-60CF
60
3
7.5
7.5
20
10
CCPB-(Poles)-70CF†
70
3
7.5
15
30
40
3
CCPB-(Poles)-90CF†
90
5
10
20
50
40
CCPB-1-50CF
1
CCPB-(Poles)-100CF†
100
5
10
20
50
40
CCPB-2-50CF
2
CCPB-3-50CF
3
CCPB-1-60CF
1
CCPB-2-60CF
2
CCPB-3-60CF
3
CCPB-1-70CF
1†
CCPB-2-70CF
2†
CCPB-3-70CF
1-40
40
TCF35RN,
TCF40RN
TCF35,
TCF40
FCF35RN,
FCF40RN
1-50
50
TCF45RN,
TCF50RN
TCF45,
TCF50
FCF45RN,
FCF50RN
1-60
60
TCF60RN
TCF60
FCF60RN
1-70
70
TCF70RN
TCF70
FCF70RN
* Split-phase
** Three-phase
† Available for a bus rating of 225A or higher.
Table 3. CCPB maximum amp ratings and CUBEFuse rejection
CCPB branch
disconnect
Maximum
circuit amps
Accepts CUBEFuse
amp ratings*
CCPB-_-15CF
15
1 to 15A
CCPB-_-20CF
20
1 to 20A
3†
CCPB-_-30CF
30
1 to 30A
CCPB-1-90CF
1†
CCPB-_-40CF
40
1 to 40A
CCPB-2-90CF
2†
CCPB-_-50CF
50
1 to 50A
CCPB-3-90CF
3†
CCPB-_-60CF
60
1 to 60A
CCPB-1-100CF
1†
CCPB-_-70CF
70
1 to 70A
CCPB-2-100CF
2†
CCPB-_-90CF
90
1 to 90A
CCPB-3-100CF
3†
CCPB-_-100CF
100
1 to 100A
1-90
1-100
90
100
*
TCF80RN
TCF90RN
TCF100RN
TCF80
TCF90
TCF100
FCF80RN
FCF90RN
FCF100RN
CCPB disconnect can accept CUBEFuses with amp ratings less than or equal to the amp
rating of the CCPB disconnect.
** Correct fit with CCPB disconnect requires indicating time-delay CUBEFuses with date code
R38 or later.
† Available for a bus rating of 225A or higher.
4
www.bussmann.com
* Always install an indicating time-delay CUBEFuse with date code R38 or later.
Quik-Spec Coordination Panelboard (QSCP)
application note
Selective coordination made easy
QSCP and upstream fuses
The QSCP provides the fusible solution for branch panelboard
applications making it simple and cost effective to selectively
coordinate the branch circuits with upstream Bussmann fuses
or upstream Eaton circuit breakers. This innovative branch circuit
panelboard uses CUBEFuse fuses (1 to 100A) for the branch circuit
protective devices. The main fusible disconnect options are Class
J Low-Peak 200A or 400A LPJ-_SP fuses or, the 30A, 60A or 100A
Compact Circuit Protector (CCP) that also utilizes the CUBEFuse.
The time-delay CUBEFuse and Low-Peak LPJ-_SP fuses are easy to
selectively coordinate with each other. CUBEfuses were tested to
selectively coordinate with Eaton circuit breakers used in upstream
power distribution panelboards and switchboards. Simply use the
published Bussmann fuse ratio and Bussmann fuse-to-Eaton circuit
breaker tables to determine selective coordination. For the purpose
of selectively coordinating a system, there is no need to plot timecurrent curves or perform a short-circuit current analysis. See page
10 to details.
Application Note 3148
Effective September 2015
A circuit with selectively coordinated overcurrent protective devices
allows only the nearest upstream overcurrent protective device
to open under any overcurrent condition. Selective coordination
increases the reliability of a system to deliver power to the loads.
Selective coordination is mandatory per the NEC® for the circuit
paths of some vital loads on specific systems including:
•
Emergency systems: 700.28
•
Legally required standby systems: 701.27
•
Critical operations power systems: 708.54
•
Critical operations data systems: 645.27
•
Elevator circuits: 620.62*
For other systems, selective coordination is a desirable design
consideration. It is in the best interest of the building owner or
tenants to have selectively coordinated overcurrent protective
devices to avoid unnecessary blackouts.
* For elevator fusible disconnects use Bussmann Quik-Spec™ Power Module™
elevator disconnect switches (PS) and panelboards (PMP). See data sheets 1145
and 1146.
Figure 1. Selectively coordinated fusible system utilizing Low-Peak and time-delay CUBEFuse fuses
Fuse selective coordination is as simple as maintaining the amp rating ratios of 2:1 (or greater) between all time-delay CUBEFuse and
Low-Peak fuses in a circuit. For other fuse types or Eaton circuit breakers, see published selective coordination tables.
* Automatic Transfer Switch (ATS) can achieve high withstand close-on rating with Low-Peak Class J fuses upstream. See Automatic Transfer Switch Protection section
in the Bussmann publication Selecting Protective Devices (SPD) handbook, publication no. 3002, for details
www.bussmann.com
5
Quik-Spec Coordination Panelboard (QSCP)
application note
Application Note 3148
Effective September 2015
Comparing fusible branch circuit panelboards
The Bussmann QSCP provides benefits over existing fusible branch
circuit panels including up to a 600Vac rating, high SCCRs up to
200kA, high interrupting rated fuses along with a broader range
of branch circuit switch amp ratings that have a unique ampacity
rejection feature that helps prevent overfusing.
Safety features include the finger-safe CUBEFuse that does not
require removing any trim components for servicing along with
a unique switch interlock on the CCPB that helps prevent fuse
removal while the circuit is energized. Table 4 illustrates several
design and safety feature comparisons versus traditional fusible
branch circuit panelboards.
Table 4. QSCP compared to traditional fusible branch circuit panelboards (MLO*)
Typical Class CC fuse
holder/circuit breaker
branch circuit arrangement
Quik-Spec™ Coordination
Panelboard
Panel configuration
SCCR
Mersen (SCP)
Littelfuse (LCP)
GE (ADS)
Square D (QMB)
Class H or
plug fuse
50kA (std.)
200kA (high)
100kA
200kA
10kA
Voltage
600V
600V
480V
600V
250V
Type
MLO
MLO
MLO
MLO
MLO
CUBEFuse™
CUBEFuse
Class CC or J**
Class H, J, K, R & T
Class H or plug
fuse
28” W x 6” D
36-44” W x 10.4” D
20” W x 6” D
$$$$
$$$$
$
Up to 100A
(1-, 2- and 3-pole)
Up to 30A
(1-pole2)
Up to 1200A
Up to 30A
(1-pole2)
15, 20, 30, 40, 50, 60, 70, 90, and
100A(rejection breaks)
Non-rejection fuse
holders(1 to 30
amps)
Rejection by fuse
case size only
Class H - no (plug
fuse rejection
requires adapters)
rejection
Up to 600Vac3
277/480V,
20/240V**120/208V
Up to 600Vac
250Vac and less
systems
UL 98 CCPB (innovative
disconnect)
Circuit breaker
UL 98 fused
disconnect
General use snap
switch
Branch fuse type
Size
20” W x 5 ¾” D 20” W x 5 ¾” D
Cost
$$
$$$
Design features
Branch-circuit amp ratings
Branch amp rating rejection feature
Panel voltage rating
Branch circuit disconnect
Safety features
Branch disconnect with integrated lockout
means
Yes
No
Yes, but defeatable
No
Interlock to prevent branch fuse removal
while energized
Yes
No
No
No
Yes (optional)
No
Yes (optional)
Yes (optional)
Lockable main disconnect(main
configuration)
* Also available with fused and non-fused main disconnects up to 400A.
**Class J and 120/240V specifications Mersen only.
1. Typical panelboard voltage ratings are 208Y/120 3-P, 4W, 120/240 1-P, 3W, and 480Y/277 3-P, 4W.
2. Multi-pole configurations may be available by special order.
3. Suitable for use on most systems up to 600Vac.
6
www.bussmann.com
Quik-Spec Coordination Panelboard (QSCP)
application note
QSCP Short-Circuit Current Ratings (SCCR)
Application Note 3148
Effective September 2015
Table 5. Panelboard short-circuit current ratings
For panelboard installations, the National Electrical Code 110.10
requires that the short-circuit current rating (SCCR) of the panelboard
be equal to or exceed the available short-circuit current at the point
of installation.
®
The QSCP is offered in a standard SCCR option or a high SCCR
option for each of the three main configurations. Refer to Table 5
and the clarifying figures that follow for examples. The SCCR is
marked on the panelboard, as well as provided in the data sheet.
Fuses in the QSCP will selectively coordinate with upstream
Bussmann fuses if upstream fuse type and amp rating meet
or exceed the published Selectivity Ratios. The QSCP will also
selectively coordinate with specific Eaton upstream circuit breakers
(see pages 13-18).
AC main options
DC
SCCR
Main
Lug Only
(MLO)*
110-200A
main disc.
no fuses*
or w/
Class J fuses
225-400A
main disc.
no fuses*
or w/
Class J fuses
30, 60 or
100A
CCP-_-_CF
main disc.**
Main
Lug Only
(MLO)*
High
200kA
200kA
100kA
200kA
100kA
Std.
50kA
50kA
50kA
50kA
20kA
* For panelboards with sub-feed main lugs, or panelboards with optional feed-through lugs,
Class J, T, or R fuses are required upstream - max amps = panel amps.
**CUBEFuse disconnect.
Figure 2. QSCP short-circuit current ratings with upstream fuses (600Vac or less system)
Example 1
Example 2
Distribution panelboard
Distribution panelboard
LPJ-200SP
200A Class J
To ensure selective
coordination, these fuses
must be Bussmann fuses
and adhere to the
published selectivity ratios
LPJ-200SP
200A Class J
Suitable for up to 200kA
available fault current
TCF15RN
X TCF60RN
Suitable for up to 50kA
available fault current
TCF15RN
X
TCF60RN
50kA SCCR
200kA SCCR
TCF20RN
TCF50RN
TCF20RN
TCF50RN
TCF30RN
TCF40RN
TCF30RN
TCF40RN
200A QSCP MLO
High SCCR Option
200A QSCP MLO
Standard SCCR Option
www.bussmann.com
7
Quik-Spec Coordination Panelboard (QSCP)
application note
Application Note 3148
Effective September 2015
Figure 3. QSCP short-circuit current ratings with upstream fuses (600Vac or less system)
Example 3
Example 4
Distribution panelboard
Distribution panelboard
LPJ-200SP
200A Class J
To ensure selective
coordination with fuses
upstream from this level,
select Bussmann fuses
and adhere to the
published selectivity ratios
LPJ-200SP
200A Class J
Suitable for up to 50kA
available fault current
Suitable for up to 200kA
available fault current
X
X
200kA SCCR
50kA SCCR
LPJ-200SP
LPJ-200SP
TCF15RN
TCF60RN
TCF15RN
TCF60RN
TCF20RN
TCF50RN
TCF20RN
TCF50RN
TCF30RN
TCF40RN
TCF30RN
TCF40RN
200A QSCP
Fused Main Disconnect
High SCCR Option
200A QSCP
Fused Main Disconnect
Standard SCCR Option
Note the upstream 200A fuses do not have to selectively coordinate with the 200A panelboard main fuses because if both open, no
additional parts of the electrical system would be unnecessarily shut down. See NEC® 700.28 and 701.27 exceptions.
Figure 4. QSCP short-circuit current ratings with upstream fuses (600Vac or less system)
Example 5
Distribution panelboard
LPJ-200SP
200A Class J
Example 6
These upstream
overcurrent protective
devices must be
Class J, RK1 or T fuses
rated 200A or less
Distribution panelboard
LPJ-200SP
200A Class J
To ensure selective
coordination with fuses
upstream from this level,
select Bussmann fuses
and adhere to the
published selectivity ratios
Suitable for up to 50kA
available fault current
Suitable for up to 200kA
available fault current
X
TCF15RN
TCF60RN
TCF20RN
TCF50RN
TCF30RN
TCF40RN
200A QSCP
Non-fused Main Disconnect
High SCCR Option
8
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200kA SCCR
when protected
upstream by
max. 200A
Class J, RK1 or T
fuses
X
TCF15RN
TCF60RN
TCF20RN
TCF50RN
TCF30RN
TCF40RN
200A QSCP
Non-fused Main Disconnect
Standard SCCR Option
50kA SCCR
when protected
upstream by
max. 200A
Class J, RK1 or T
fuses
Quik-Spec Coordination Panelboard (QSCP)
application note
Application Note 3148
Effective September 2015
How to achieve selective coordination
The QSCP saves the designer time and provides an easy means
to selectively coordinate lighting and other branch circuits with
upstream Bussmann fuses or Eaton circuit breakers.
Selective coordination increases the reliability of an electrical system
to provide availability of power to vital loads.
For selective coordination with upstream Eaton circuit breakers, go
to page 12.
The system on the right illustrates selective coordination: for the
full range of overcurrents possible for this system, only the nearest
upstream overcurrent protective device opens. No other upstream
overcurrent protective devices open and interruption of power is
minimized to the fewest loads. Similarly, the fault could also occur
on a feeder circuit and a selectively coordinated circuit would result
in only the nearest upstream feeder overcurrent protective device
opening.
The two one-line diagrams in Figure 5 below demonstrate the
concept of selective coordination.
The one-line diagram on the left illustrates a lack of selective
coordination. A fault on the loadside of one overcurrent protective
device unnecessarily opens other upstream overcurrent protective
devices. The result is unnecessary power loss to loads that should
not be affected by the fault.
The NEC® definition in Article 100:
Coordination (Selective). Localization of an overcurrent condition
to restrict outages to the circuit or equipment affected,
accomplished by the selection and installation of overcurrent
protective devices and their ratings or settings for the full
range of available overcurrents, from overload to the maximum
available fault current, and for the full range of overcurrent
protective device opening times associated with those
overcurrents.
Figure 5. Electrical system selective coordination
Without selective coordination
Opens
Opens
Not affected
With selective coordination
Fault
Not affected
Fault
Unnecessary power loss
www.bussmann.com
9
Quik-Spec Coordination Panelboard (QSCP)
application note
Application Note 3148
Effective September 2015
Figure 6. Selectively coordinated QSCP
Switchboard
Normal
source
Alternate
source
KRP-C-800SP
LPJ-_SP
LPJ-_SP
KRP-C-800SP
6
LPJ-400SP
5
*
N
LPJ-400SP
E
4
3
ATS
Distribution panelboard
LPJ-_SP
LPJ-200SP
LPJ-_SP
TCF15RN
TCF60RN
TCF20RN
TCF50RN
TCF30RN
TCF40RN
2
1
* Fuse 5 is not required to selectively
coordinate with fuse 6 by NEC® 700.28.
However, it is a good design practice for
fuse 5 to selectively coordinate with
fuse 6 because continuity of service
is greatly improved.
Quik-Spec Coordination
Panelboard
Selective coordination is as simple as maintaining amp rating ratios of 2:1 or greater between time-delay CUBEFuse and Low-Peak fuses in a
circuit. For other fuse types see Selectivity Ratio Guide.
Example analysis
Designers have been selectively coordinating fused systems by
using the Bussmann Selectivity Ratio Guide (page 11). Now, the
QSCP permits designers to ensure selective coordination for branch
circuits fed from branch circuit panelboards. In Figure 6 above is a
one-line example of how simple selective coordination analysis is
with Bussmann fuses.
Check the upstream feeder fuse at location 2 with the largest
branch circuit fuse at location 1:
The as-designed amp ratio of feeder LPJ-200SP to branch TCF60RN
(largest branch) is 3.3:1 and the published selectivity ratio to ensure
coordination is 2:1. (Note the time-delay TCF60RN is the nonindicating version of the TCF CUBEFuse.)
As long as the as-designed ratio is 2:1 or greater, then selective
coordination is achieved. Since 3.3:1 is greater than 2:1, the LPJ200SP fuse is selectively coordinated with the TCF60RN fuse for
any overcurrent up to 200kA.
The other TCF-_RN fuses in the panelboard have an amp rating
lower than 60A, so they, too, will selectively coordinate with the
LPJ-200SP fuse.
10
www.bussmann.com
The analysis should be completed for both the circuit path from the
QSCP branch TCF-_RN fuses to the service fuses on the normal
path as well as the circuit path to the alternate source feeder fuses.
The as-designed amp ratios must be equal to or greater than the
published ratios in the Selectivity Ratio Guide for the following
(analyzed fuses in Figure 6 have been assigned numbers 1 to 6):
•
TCF60RN fuse at 1 with fuses at 2 (distribution panelboard), 3 and
4 (alternate source), 5 and 6 (normal source)
•
LPJ-200SP fuse at 2 with fuses 3 and 4 (alternate source), 5 and
6 (normal source)
•
LPJ-400SP fuse at 3 with fuse 4 (alternate source).
•
LPJ-400SP fuse at 5 with fuse 6 (normal source)*
The published ratios in the Selectivity Ratio Guide for all the fuse
combinations above are 2:1. In all cases, the as-designed ratios,
in the above example are 2:1 or greater. Therefore, fuse selective
coordination is ensured for the circuit paths from the fuses in the
QSCP to the normal source, as well as to the alternate source.
Quik-Spec Coordination Panelboard (QSCP)
application note
Application Note 3148
Effective September 2015
Selective coordination using fuses
Adhering to published fuse selectivity ratios makes it easy to design
and install a selectively coordinated fusible system. In the Selectivity
Ratio Guide below, the top horizontal axis shows loadside fuses and
the left vertical axis shows lineside fuses covering selectivity ratios
for all levels of overcurrents up to the fuse interrupting ratings or
200kA, whichever is lower.
These ratios are valid for all overcurrents and opening times. The
designer just needs to specify the proper amp rating.
There is no need to plot time-current curves or do a short-circuit
current analysis to determine selective coordination (if the available
short-circuit current is less than 200kA or the interrupting rating of
the fuses, whichever is less).
To assure selective coordination, just make sure the fuses and amp
rating ratios for the mains, feeders and branch circuits meet or
exceed the applicable selectivity ratios in Table 6.
If the ratios are not satisfied, then the designer should investigate
another fuse type or design change.
Table 6. Selectivity ratio guide (upstream/lineside to downstream/loadside)1
Circuit
Downstream / loadside fuse
Amp rating
range
6016000A
6014000A
1-100A
0-600A
6016000A
0-600A
0-1200A
0-600A
0-60A
Timedelay
Timedelay
Time-delay
Dual-element, time-delay
Fastacting
Fastacting
Fastacting
Fastacting
Timedelay
Low-Peak
(L)
Limitron
(L)
CUBEFuse
(CF2)
Low-Peak
(J)
Low-Peak
(RK1)
Fusetron
(RK5)
Limitron
(L)
Limitron
(RK1)
Limitron
(T)
Limitron
(J)
SC
(G)
(CC)
Bussmann
fuse
symbol
KRP-C_SP
KLU
TCF
LPJ-SP
LPN-RK_SP
LPS-RK_SP
FRN-R
FRS-R
KTU
KTN-R
KTS-R
JJN
JJS
JKS
SC
LP-CC
FNQ-R
KTK-R
KRP-C_SP
2:1
2.5:1
2:1
2:1
2:1
—
—
—
—
—
—
2:1
Fuse
type
Upstream / lineside fuse
Trade name
(fuse class)
0-30A
601 to 6000A
Timedelay
Low-Peak
(L)
601 to 4000A
Timedelay
Limitron
(L)
KLU
2:1
2:1
2:1
2:1
2:1
4:1
2:1
2:1
2:1
2:1
2:1
2:1
0 to 600A
Dualelement
Low-Peak
(RK1)
LPN-RK_SP
LPS-RK_SP
—
—
2:1
2:1
2:1
8:1
—
3:1
3:1
3:1
4:1
2:1
0 to 600A
Dualelement
Low-Peak
(J)
LPJ-SP
—
—
2:1
2:1
2:1
8:1
—
3:1
3:1
3:1
4:1
2:1
0 to 100A
Dualelement
CUBEFuse
(CF2)
TCF
—
—
2:1
2:1
2:1
8:1
—
3:1
3:1
3:1
4:1
2:1
0 to 600A
Dualelement
Fusetron
(RK5)
FRN-R
FRS-R
—
—
1.5:1
1.5:1
1.5:1
2:1
—
1.5:1
1.5:1
1.5:1
1.5:1
2:1
601 to 6000A
Fastacting
Limitron
(L)
KTU
2:1
2.5:1
3:1
3:1
3:1
6:1
2:1
2:1
2:1
2:1
2:1
2:1
0 to 600A
Fastacting
Limitron
(RK1)
KTN-R
KTS-R
—
—
3:1
3:1
3:1
8:1
—
3:1
3:1
3:1
4:1
—
0 to 1200A
Fastacting
Limitron
(T)
JJN
JJS
—
—
3:1
3:1
3:1
8:1
—
3:1
3:1
3:1
4:1
—
0 to 600A
Fastacting
Limitron
(J)
JKS
—
—
3:1
3:1
3:1
8:1
—
3:1
3:1
3:1
4:1
—
0 to 60A
Timedelay
SC
(G)
SC
—
—
3:1
3:1
3:1
4:1
—
2:1
2:1
2:1
2:1
—
General notes: Ratios given in this table apply to only Bussmann fuses. When fuses are within the same case size, consult Bussmann.
1. Where applicable, ratios are valid for indicating and non-indicating versions of the same fuse. At some values of fault current, specified ratios may be lowered to
permit closer fuse sizing. Consult Bussmann.
2. Time-delay Class CF TCF or TCF_RN CUBEFuses are 1 to 100A Class J performance; dimensions and construction are a unique, finger-safe design.
www.bussmann.com
11
Quik-Spec Coordination Panelboard (QSCP)
application note
Application Note 3148
Effective September 2015
Selective coordination using upstream Eaton circuit breakers
Notes on the QSCP
The tables on pages 13 to 18 show the upstream/lineside Eaton
thermal magnetic circuit breakers that have been tested to
selectively coordinate with downstream/loadside time-delay or fastacting CUBEFuses up through the interrupting rating of the lineside
circuit breaker.
The QSCP is a highly configurable fusible panelboard that can be
installed on systems up to 600Vac, three-phase.
Coordination tables are presented for 240Vac, 480Vac and 600Vac
systems covering the tested breaker frame, family and the minimum
and maximum amp ratings. The available Eaton Pow-R-Line panels
for which those circuit breakers can be applied are also presented.
As covered earlier in this guide and summarized in the table below
the QSCP can be ordered with high 200kA or standard 50kA
assembly SCCRs:
•
Panel ratings of 30, 60, 100, 200 and 400 amps
•
Three main options
• MLO
Test results are also summarized in “quick-pick” tables that
are limited to system voltage, circuit breaker frame, family and
maximum and minimum amp rating.
•
Using the coordination tables
To use the MCCB/CUBEFuse Selective Coordination Combination
tables, available fault current to which selective coordination
must be achieved and system voltage must be known. With this
information, perform the following:
Use the system voltage to determine the applicable table
•
Locate the desired downstream CUBEFuse ampacity in the lower
left hand column and read across the row for those values greater
than the available fault current.
•
Each column where the value exceeds the available fault current
presents a possible upstream circuit breaker solution that will
selectively coordinate to the maximum available fault current
available.
•
From the top section of the table, where the table kA exceeds the
available fault current, locate the desired upstream Eaton circuit
breaker frame and family with a minimum amp setting less than
or equal to that which will protect the feeder circuit conductor
•
The circuit breaker and the fuse will selectively coordinate for all
values of overloads and short-circuits up to the values shown (kA).
Using the quick-pick tables
•
Non-fused switch
•
Fused switch
1-, 2- or 3-pole branch circuit disconnects
NOTE: For purposes of this guide, only the MLO, non-fused main
switch and 30, 60 and 100 amp main switch options are covered by
the upstream circuit breaker coordination tables.
The 30, 60 and 100 amp main fused switch options use the
Bussmann Compact Circuit Protector (CCP).
The branch circuit disconnect switches are the Bussmann Compact
Circuit Protector Base (CCPB).
Both the CCP and CCPB are ampacity rejecting and will hold
any time-delay or fast-acting CUBEFuse up to their amp rating.
CUBEFuses with an amp rating greater than the switch cannot be
installed.
When determining which 30, 60 or 100A fused main switch to
select, size the switch to the lowest rating possible with the
desired CUBEFuse ampacity. E.g., in a 240V system, if you want to
selectively coordinate the GHB 100, the largets CUBEFuse that can
be applied is 50 amps. This 50 amp CUBEFuse must be installed in
a CCP greater than 30A. This would be the 60 or 100A CCP.
When working with MLO or non-fused main disconnect switch
versions of the QSCP, this same consideration for ampacity rejection
is applied to the CCPB branch disconnect switches.
The“quick-pick” tables (tables 7, 8 and 9) present the same
information as the coordination tables, only they omit the Pow-RLine panel and QSCP information. They simply present solutions for
the same system voltages and circuit breakers/amp ratings along
with the permissible CUBEFuse ampacity. If you want to quickly
determine if an upstream circuit breaker and the ampacity of a
downstream CUBEFuse will selectively coordinate, start with these
tables.
QSCP Panelboard Mains and Branch Disconnect Switches
Main options
Panelboard
amp ratings
MLO
Non-fused
switch
Fused
amps
switch amps
Fused main switch
Amp range / fuses
400
400
400A switch
225-400A Bussmann series time-delay LPJ-_SP
UL Class J Fuses
200
200
200A switch
110-200A Bussmann series time-delay LPJ-_SP
UL Class J Fuses
100
100A CCP
1-100A Bussmann series time-delay (TCF) or
fast-acting (FCF) CUBEFuse UL Class CF Fuses
60
60
60A CCP
1-60A Bussmann series time-delay (TCF) or fastacting (FCF) CUBEFuse UL Class CF Fuses
30
30
30A CCP
1-30A Bussmann series time-delay (TCF) or fastacting (FCF) CUBEFuse UL Class CF Fuses
100
12
Yes
www.bussmann.com
Fused branches
Branch disconnect
switches
Branch amp rating
(fuse amp range)
1-, 2-, 3-pole CCPB
15
30
50
70
(≤15A), 20 (≤20A),
(≤30A), 40 (≤40A),
(≤50A), 60 (≤60A),
(≤70A), 90 (≤90A),
100 (≤100A)
Quik-Spec Coordination Panelboard (QSCP)
application note
Application Note 3148
Effective September 2015
Table 7. 240Vac Eaton thermal magnetic circuit breaker “quick pick” selective coordination with CUBEFuse amp ratings*
Eaton lineside circuit breakers
Breaker frame
G Frame
E Frame
F Frame
J Frame
K Frame
Breaker family
Min. amp rating
Max amp rating
Max circuit
fault current (kA)
GHB
100
100
65
Loadside CUBEFuse (time-delay or fast-acting)
TCF or FCF amp ratings**
15, 20, 25, 30, 35, 40, 50
EGB
125
125
25
15, 20, 25, 30, 35, 40, 50, 60
EHD
100
100
18
15, 20, 25, 30, 35, 40, 50
FD
100
100
65
15, 20, 25, 30, 35, 40, 50
FD
150
150
65
15, 20, 25, 30, 35, 40, 50, 60, 70
FD
225
225
65
15, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100
JD
70
70
65
15, 20, 25, 30
JD
150
150
65
15, 20, 25, 30, 35, 40, 50, 60, 70
KD
200
400
65
15, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100
HKD
400
400
100
15, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100
* For circuit breakers with an adjustable instantaneous trip, selective coordination is based upon instantaneous trip set at maximum.
** TCF (time-delay) and FCF (fast-acting) 600Vac fuses can be used on any 600Vac or less system. The CUBEFuses have an interrupting rating of 300kA at 600Vac or less.
Table 8. 480Vac Eaton thermal magnetic circuit breaker “quick pick” selective coordination with CUBEFuse amp ratings*
Eaton lineside circuit breakers
Min. amp rating
Max amp rating
Max circuit
fault current (kA)
G Frame
GHB
100
100
14†
15, 20, 25, 30, 35, 40, 50
E Frame
EGB
125
125
18
15, 20, 25, 30, 35, 40, 50, 60
EHD
100
100
14
15, 20, 25, 30, 35, 40, 50
FD
100
100
35
15, 20, 25, 30, 35, 40, 50
FD
150
150
35
15, 20, 25, 30, 35, 40, 50, 60, 70
FD
225
225
35
15, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100
F Frame
J Frame
K Frame
Loadside CUBEFuse (time-delay or fast-acting)
Breaker family
Breaker frame
TCF or FCF amp ratings**
JD
70
70
35
15, 20, 25, 30
JD
150
150
35
15, 20, 25, 30, 35, 40, 50, 60, 70
KD
200
400
35
15, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100
HKD
400
400
65
15, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100
* For circuit breakers with an adjustable instantaneous trip, selective coordination is based upon instantaneous trip set at maximum.
** TCF (time-delay) and FCF (fast-acting) 600Vac fuses can be used on any 600Vac or less system. The CUBEFuses have an interrupting rating of 300kA at 600Vac or less.
†480/277Vac
Table 9. 600Vac Eaton thermal magnetic circuit breaker “quick pick” selective coordination with CUBEFuse amp ratings*
Eaton lineside circuit breakers
Breaker frame
F Frame
J Frame
K Frame
L Frame
Breaker family
Min. amp rating
Max amp rating
Max circuit
fault current (kA)
FD
100
100
18
Loadside CUBEFuse (time-delay or fast-acting)
TCF or FCF amp ratings**
15, 20, 25, 30, 35, 40, 50
FD
150
150
18
15, 20, 25, 30, 35, 40, 50, 60, 70
FD
225
225
18
15, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100
JD
70
70
18
15, 20, 25, 30
15, 20, 25, 30, 35, 40, 50, 60, 70
JD
150
150
18
KD
200
400
25
15, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100
HKD
400
400
35
15, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100
LD
300
600
25
15, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100
HLD
300
600
35
15, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100
* For circuit breakers with an adjustable instantaneous trip, selective coordination is based upon instantaneous trip set at maximum.
** TCF (time-delay) and FCF (fast-acting) 600Vac fuses can be used on any 600Vac or less system. The CUBEFuses have an interrupting rating of 300kA at 600Vac or less.
www.bussmann.com
13
Quik-Spec Coordination Panelboard (QSCP)
application note
Application Note 3148
Effective September 2015
Table 10. MCCB/CUBEFuse Selective Coordination Combinations* — all values in kAIR rms at 240Vac
Breaker Frame
Upstream Breaker
G Frame
E Frame
Circuit Breaker Family
GHB
EGB
EHD
FD
FD
FD
Trip Unit Type
T/M
T/M
T/M
T/M
T/M
T/M
Minimum Amp Rating
100A
125A
100A
100A
150A
225A
Maximum Amp Rating
100A
125A
100A
100A
150A
225A
2a
3E
2a, 3a, 4
3E
3a, 4,
Swbd
3a, 4,
Swbd
3a, 4,
Swbd
3a, 4,
Swbd
—
—
1a, 2a
1a, 2a
1a, 2a
1a, 2a
Pow-R-Line: Main
Downstream Fuse
Pow-R-Line: Branch
Pow-R-Line: Sub-Feed
CUBEFuse (TCF/FCF)**
Main
15
QSCP
with 30A
switch***
20
25
30
35
QSCP
with 60A
switch***
40
50
60
70
QSCP
with 100A
switch***
80
90
100
Branch
1a, 2a, 3a 1a, 2a, 3a 1a, 2a, 3a 1a, 2a, 3a
Lineside circuit breakers selectively coordinate with
downstream CUBEFuses up to the
circuit breaker interrupting ratings listed below
Fusible Panel
Fuse amps
F Frame
Sub-Feed****
QSCP
—
65
25
18
65
65
65
QSCP
—
65
25
18
65
65
65
QSCP
—
65
25
18
65
65
65
QSCP
—
65
25
18
65
65
65
QSCP
—
65
25
18
65
65
65
QSCP
—
65
25
18
65
65
65
QSCP
—
65
25
18
65
65
65
QSCP
—
—
25
—
—
65
65
QSCP
—
—
—
—
—
65
65
QSCP
—
—
—
—
—
—
65
QSCP
—
—
—
—
—
—
65
QSCP
—
—
—
—
—
—
65
Table 11. MCCB Selective Coordination Combinations* — all values in kAIR rms at 240Vac
Breaker Frame
Upstream Breaker
JD
KD
KD
Trip Unit Type
T/M
T/M
T/M
T/M
T/M
Minimum Amp Rating
70A
150A
200A
400A
400A
Maximum Amp Rating
70A
150A
200A
400A
400A
1a, 2a,
3a, 3E, 4,
Swbd
Pow-R-Line: Branch
Pow-R-Line: Sub-Feed
—
—
—
4, Swbd
4, Swbd
4, Swbd
4, Swbd
4, Swbd
—
—
—
—
—
20
25
Lineside circuit breakers selectively coordinate with
downstream CUBEFuses up to the
circuit breaker interrupting ratings listed below
Fusible Panelboard
Main
15
QSCP
with 30A
switch***
HKD
1a, 2a,
3a, 3E, 4,
Swbd
CUBEFuse (TCF/FCF)**
Fuse amps
K Frame
JD
Pow-R-Line: Main
Downstream Fuse
J Frame
Circuit Breaker Family
Branch
Sub-Feed****
QSCP
—
65
65
65
65
100
QSCP
—
65
65
65
65
100
QSCP
—
65
65
65
65
100
30
QSCP
—
65
65
65
65
100
35
QSCP
—
—
65
65
65
100
QSCP
—
—
65
65
65
100
QSCP
—
—
65
65
65
100
60
QSCP
—
—
65
65
65
100
70
QSCP
—
—
65
65
65
100
QSCP
—
—
—
65
65
100
QSCP
—
—
—
65
65
100
QSCP
—
—
—
65
65
100
40
50
80
90
QSCP
with 60A
switch***
QSCP
with 100A
switch***
100
* For circuit breakers with an adjustable instantaneous trip, selective coordination is based upon instantaneous trip set at maximum.
** TCF (time-delay) and FCF (fast-acting) 600Vac fuses can be used on any 600Vac or less system. The CUBEFuses have an interrupting rating of 300kA at 600Vac or less.
*** The mains consist of main CCP switch and fuses. A CCP switch of a specific amp rating can accept any CUBEFuse of that same amp rating or less.
**** Sub-feed switch with LPJ-(amp)SP fuses are an option for the QSCP panels. However, at time of publication selective coordination testing results are not available for LPJ fuses to upstream
Eaton circuit breakers.
14
www.bussmann.com
Quik-Spec Coordination Panelboard (QSCP)
application note
Application Note 3148
Effective September 2015
Table 12. MCCB/CUBEFuse Selective Coordination Combinations* — all values in kAIR rms at 480Vac
Frame Family
Upstream Breaker
G Frame
E Frame
Circuit Breaker Family
GHB
EGB
EHD
FD
FD
FD
Trip Unit Type
T/M
T/M
T/M
T/M
T/M
T/M
Minimum Amp Rating
100A
125A
100A
100A
150A
225A
Maximum Amp Rating
100A
125A
100A
100A
150A
225A
2a†
Pow-R-Line: Main
Downstream Fuse
Pow-R-Line: Branch
Pow-R-Line: Sub-Feed
3E
2a†, 3a
2a†, 3a
2a†, 3a
2a†, 3a
2a†, 3a†,
4†
3E
3a, 4,
Swbd
3a, 4,
Swbd
3a, 4,
Swbd
3a, 4,
Swbd
—
—
2a†
2a†
2a†
2a†
CUBEFuse (TCF/FCF)**
Main
15
20
25
Lineside circuit breakers selectively coordinate with
downstream CUBEFuses up to the
circuit breaker interrupting ratings listed below
Fusible Panelboard
Fuse amps
QSCP
with 30A
switch***
F Frame
Branch
Sub-Feed****
QSCP
—
14
18
14
35
35
35
QSCP
—
14
18
14
35
35
35
QSCP
—
14
18
14
35
35
35
30
QSCP
—
14
18
14
35
35
35
35
QSCP
—
14
18
14
35
35
35
40
50
QSCP
with 60A
switch***
QSCP
—
14
18
14
35
35
35
QSCP
—
14
18
14
35
35
35
60
QSCP
—
—
18
—
—
35
35
70
QSCP
—
—
—
—
—
35
35
QSCP
—
—
—
—
—
—
35
80
90
QSCP
with 100A
switch***
100
QSCP
—
—
—
—
—
—
35
QSCP
—
—
—
—
—
—
35
Table 13. MCCB Selective Coordination Combinations* — all values in kAIR rms at 480Vac
Frame Family
Upstream Breaker
JD
KD
KD
HKD
Trip Unit Type
T/M
T/M
T/M
T/M
T/M
400A
Minimum Amp Rating
70A
150A
200A
400A
Maximum Amp Rating
70A
150A
200A
400A
400A
2a†, 3a, 3E,
4, Swbd
Pow-R-Line: Branch
Pow-R-Line: Sub-Feed
—
—
—
2a†, 3a, 3E,
4, Swbd
4, Swbd
4, Swbd
4, Swbd
4, Swbd
4, Swbd
—
—
—
—
—
CUBEFuse (TCF/FCF)**
Fuse amps
20
25
Main
QSCP
with 30A
switch***
30
35
40
50
QSCP
with 60A
switch***
60
70
80
90
100
Lineside circuit breakers selectively coordinate with
downstream CUBEFuses up to the
circuit breaker interrupting ratings listed below
Fusible Panelboard
15
QSCP
with 100A
switch***
Branch
K Frame
JD
Pow-R-Line: Main
Downstream Fuse
J Frame
Circuit Breaker Family
Sub-Feed****
QSCP
—
35
35
35
35
65
QSCP
—
35
35
35
35
65
QSCP
—
35
35
35
35
65
QSCP
—
35
35
35
35
65
QSCP
—
—
35
35
35
65
QSCP
—
—
35
35
35
65
QSCP
—
—
35
35
35
65
QSCP
—
—
35
35
35
65
QSCP
—
—
35
35
35
65
QSCP
—
—
—
35
35
65
QSCP
—
—
—
35
35
65
QSCP
—
—
—
35
35
65
* For circuit breakers with an adjustable instantaneous trip, selective coordination is based upon instantaneous trip set at maximum.
** TCF (time-delay) and FCF (fast-acting) 600Vac fuses can be used on any 600Vac or less system. The CUBEFuses have an interrupting rating of 300kA at 600Vac or less.
*** The mains consist of main CCP switch and fuses. A CCP switch of a specific amp rating can accept any CUBEFuse of that same amp rating or less.
**** Sub-feed switch with LPJ-(amp)SP fuses are an option for the QSCP panels. However, at time of publication selective coordination testing results are not available for LPJ fuses to upstream
Eaton circuit breakers.
†480/277Vac
www.bussmann.com
15
Quik-Spec Coordination Panelboard (QSCP)
application note
Application Note 3148
Effective September 2015
Table 14. MCCB/CUBEFuse Selective Coordination Combinations* — all values in kAIR rms at 600Vac
Frame Family
Upstream Breaker
F Frame
Circuit Breaker Family
FD
FD
FD
Trip Unit Type
T/M
T/M
T/M
Minimum Amp Rating
100A
150A
225A
Maximum Amp Rating
100A
150A
225A
3a
3a
3a
3a, 4, Swbd
3a, 4, Swbd
3a, 4, Swbd
—
—
—
Pow-R-Line: Main
Downstream Fuse
Pow-R-Line: Branch
Pow-R-Line: Sub-Feed
CUBEFuse (TCF/FCF)**
Lineside circuit breakers selectively coordinate with
downstream CUBEFuses up to the
circuit breaker interrupting ratings listed below
Fusible Panelboard
Fuse amps
Main
15
QSCP
with 30A
switch***
20
25
Branch
Sub-Feed****
QSCP
—
18
18
18
QSCP
—
18
18
18
18
QSCP
—
18
18
30
QSCP
—
18
18
18
35
QSCP
—
18
18
18
QSCP
—
18
18
18
QSCP
—
18
18
18
60
QSCP
—
—
18
18
70
QSCP
—
—
18
18
QSCP
—
—
—
18
QSCP
—
—
—
18
QSCP
—
—
—
18
QSCP
with 60A
switch***
40
50
QSCP
with 100A
switch***
80
90
100
Table 15. MCCB Selective Coordination Combinations* — all values in kAIR rms at 600Vac
Frame Family
Upstream Breaker
Trip Unit Type
T/M
T/M
T/M
T/M
T/M
Minimum Amp Rating
70A
150A
200A
400A
400A
Maximum Amp Rating
70A
150A
200A
400A
400A
3a, 3E, 4,
Swbd
Pow-R-Line: Branch
Pow-R-Line: Sub-Feed
KD
KD
HKD
—
—
—
4, Swbd
4, Swbd
4, Swbd
4, Swbd
4, Swbd
—
—
—
—
—
Lineside circuit breakers selectively coordinate with
downstream CUBEFuses up to the
circuit breaker interrupting ratings listed below
Fusible Panelboard
Main
JD
3a, 3E, 4,
Swbd
CUBEFuse (TCF/FCF)**
Fuse amps
K Frame
JD
Pow-R-Line: Main
Downstream Fuse
J Frame
Circuit Breaker Family
Branch
Sub-Feed****
QSCP
—
18
18
25
25
35
QSCP
—
18
18
25
25
35
QSCP
—
18
18
25
25
35
30
QSCP
—
18
18
25
25
35
35
QSCP
—
—
18
25
25
35
QSCP
—
—
18
25
25
35
15
20
25
40
50
QSCP
with 30A
switch***
QSCP
with 60A
switch***
QSCP
—
—
18
25
25
35
60
QSCP
—
—
18
25
25
35
70
QSCP
—
—
18
25
25
35
QSCP
—
—
—
25
25
35
QSCP
—
—
—
25
25
35
QSCP
—
—
—
25
25
35
80
90
QSCP
with 100A
switch***
100
* For circuit breakers with an adjustable instantaneous trip, selective coordination is based upon instantaneous trip set at maximum.
** TCF (time-delay) and FCF (fast-acting) 600Vac fuses can be used on any 600Vac or less system. The CUBEFuses have an interrupting rating of 300kA at 600Vac or less.
*** The mains consist of main CCP switch and fuses. A CCP switch of a specific amp rating can accept any CUBEFuse of that same amp rating or less.
**** Sub-feed switch with LPJ-(amp)SP fuses are an option for the QSCP panels. However, at time of publication selective coordination testing results are not available for LPJ fuses to upstream
Eaton circuit breakers.
16
www.bussmann.com
Quik-Spec Coordination Panelboard (QSCP)
application note
Application Note 3148
Effective September 2015
Application and fuse sizing guidelines
Individual lighting ballast protection recommendation
CUBEFuse sizing guide
Bussmann provides in-line fuses/holders for the specific purpose
of isolating individual luminaires when an internal fault occurs.
See example in Figure 8. If a ballast fails, the low amp rated
in-line fuse quickly opens without opening the branch circuit
overcurrent protective device or the service ground fault protection,
and therefore isolates just the one faulted luminaire. The other
luminaires on the lighting branch circuit remain in operation. The
GLR/HLR or GLQ/HLQ fuse/holder combination are typically used
for this application. See data sheet nos. 2032 and 2033. Fuse amp
rating should be per luminaire manufacturer’s recommendation.
The time-delay CUBEFuses permit closer fuse sizing than non-time
delay fuses for loads with inrush currents such as transformers or
across the line AC motors. The CUBEFuse has excellent currentlimiting characteristics (UL Class J) which results in superior shortcircuit protection for circuit components and outstanding arc flash
hazard mitigation when the arcing current is within the currentlimiting range of the fuse. In addition, these fuses are rated 600Vac
and have a 300kA interrupting rating.
Branch circuits, lighting and appliance loads (no motors)
For lighting branch circuits, a common application for QSCP branch
circuits, the CUBEFuse and conductors are sized at the rated circuit
ampacity. The branch circuit conductor (per NEC® 210.19(A)(1)) and
fuse (per NEC® 210.20(A)) must be sized for the non-continuous load
plus 125% of the continuous load. Most lighting branch circuits are
continuous loads, so a branch circuit with a 16A lighting load (16A x
125% = 20A) would require a 20A branch circuit rating with 12 AWG
75°C copper conductor and 20A CUBEFuse. (This is before any
NEC® adjustment or correction factors that may apply.) See example
in Figure 7.
Figure 7. CCPB disconnect/CUBEFuse sized for lighting
branch circuit
Figure 8. Fusing individual luminaires
Distribution panelboard
Luminaires
LPJ-200SP
200A Class J
Faulted ballast
TCF20RN
TCF20RN
TCF20RN
TCF20RN
TCF20RN
TCF20RN
X
…
Supplementary
protection
(GLR-3 fuses)
Distribution panelboard
Luminaires
LPJ-200SP
200A QSCP MLO
200A Class J
Ballasts
TCF20RN
TCF20RN
TCF20RN
TCF20RN
TCF20RN
TCF20RN
200A QSCP MLO
This fuse opens and isolates one individual luminaire
…
16A continuous load
12AWG 75°C Cu conductor
20A branch circuit
TCF20RN CUBEFuse with CCPB-20 disconnect
GLR fuse and HLR in-line fuse holder.
www.bussmann.com
17
Quik-Spec Coordination Panelboard (QSCP)
application note
Application Note 3148
Effective September 2015
Branch circuits: Individual motor circuits
Applying Quik-Spec Coordination Panelboards
The CUBEFuse provides excellent motor branch circuit short-circuit
and ground-fault protection per NEC® 430.52 for an individual
motor on a branch circuit. Based on the motor full load amps from
NEC® Tables 430.248 to 430.250, there are three different sizing
alternatives to consider. See the CUBEFuse motor sizing table at the
end of this section. An example is in Figure 9.
The panelboard Short-Circuit Current Rating (SCCR) must be greater
than the available short-circuit current. See the section QSCP: ShortCircuit Current Rating (SCCR) in this publication for more details on
this subject.
Optimal branch circuit protection - 150% or the next larger
CUBEFuse amp rating if 150% does not correspond to a fuse
amp rating. This provides the greatest degree of short-circuit and
ground-fault protection for motor branch circuits (NEC® 430.52), but
typically is not the maximum sizing allowed. If a motor has a long
starting time, high starting current profile or is cycled frequently, it
may be necessary to use one of the next two sizing guidelines. In
some cases for the CUBEFuse Motor Sizing Table at the end of this
section, the fuse size is slightly less than 150%. This can provide
slightly better protection and in some cases, be less cost.
Each panelboard must be individually protected within the
panelboard (fused main disconnect) or on the supply side by a set
of fuses or circuit breaker having an amp rating not greater than the
panelboard (NEC® 408.36). See Figure 10.
Figure 10. QSCP overcurrent protection
Distribution panelboard
Maximum branch circuit protection size, general applications (code
max) - 175% or the next larger (NEC® 240.6) standard fuse amp
rating if 175% does not correspond to a standard fuse amp rating
(NEC® 430.52(C)(1) Exc. 1).
Maximum branch circuit protection size, heavy start - Where sizing
at 175% is not sufficient for the starting current of the motor, size at
225% or the next smaller CUBEFuse amp rating if 225% does not
correspond to a CUBEFuse fuse amp rating (NEC® 430.52(C)(1) Exc.
2).
For any of the alternatives above, motor running overload protection
(NEC® 430.32) needs to be provided by other means such as an
overload relay. If the motor controller manufacturer’s overload relay
tables state a maximum branch circuit protective device of a lower
rating, that lower rating must be used in lieu of the sizes determined
above. Finally, the Compact Circuit Protector Base (CCPB)
disconnect must have a horsepower rating equal to or greater than
the motor horsepower rating.
Bussmann recommends using indicating time-delay CUBEFuses on
motor branch circuits for easy, positive viewing of fuse status.
Figure 9. CUBEFuse/CCPB disconnect sized for optimal
motor branch circuit protection
Distribution panelboard
LPJ-200SP
200A Class J
CCPB-30 disconnect with
TCF25RN CUBEFuse
TCF20RN
TCF20RN
TCF20RN
TCF25RN
TCF20RN
TCF20RN
12AWG 75°C Cu conductor
Motor starter with overload
protection based on motor
nameplate FLA per
NEC® 430.32
200A QSCP MLO
10Hp motor
three-phase, 460V
NEC® Table 430.250
14A for determining branch circuit
protective device
18
www.bussmann.com
Distribution panelboard
LPJ-200SP
LPJ-200SP
200A Class J
200A Class J
Panelboard protected
by main fuses
LPJ-200SP
TCF15RN
TCF60RN
TCF20RN
TCF50RN
TCF30RN
TCF40RN
Panelboard protected
by upstream fuses
TCF15RN
TCF60RN
TCF20RN
TCF50RN
TCF30RN
TCF40RN
200A QSCP MLO
200A QSCP
Fused Main Disconnect
Quik-Spec Coordination Panelboard (QSCP)
application note
If the panelboard is supplied through a transformer, the fuses for
the protection of the panelboard must be located on the transformer
secondary per NEC® 408.36(B). See Figure 11. An exception
is where a panelboard supplied by a single-phase, two-wire or
three-phase, three-wire, delta-delta transformer is permitted to be
protected by a set of fuses or a circuit breaker on the primary where
the protection complies with NEC® 240.21(C)(1) which requires:
Application Note 3148
Effective September 2015
2.The overcurrent protective device on the primary of the
transformer does not exceed the ampacity of the secondary
conductor (or amp rating of the panelboard), multiplied by the
secondary to primary voltage ratio. Selecting the next higher
standard size overcurrent protective device is NOT allowed.
1.The transformer is protected in accordance with 450.3. The
maximum fuse permitted for 600V or less, transformer primary
only protection per NEC® 450.3(B) is 125% of transformer
primary rated current or the next standard amp rating in NEC®
240.6 if 125% of this current does not correspond to a standard
fuse amp rating.
Figure 11. QSCP supplied through a transformer
Distribution panelboard
Distribution panelboard
LPJ-(amp)SP
LPJ-XXXSP
J-
Class J
XXXA Class J
Transformer
single-phase, two wire
or
three-phase, three wire
Delta-Delta
Panelboard protected
by main fuses
TCF15RN
TCF60RN
LPJ-200SP
TCF20RN
TCF50RN
TCF15RN
TCF60RN
TCF30RN
TCF40RN
TCF20RN
TCF50RN
TCF30RN
TCF40RN
In this case, fuses on the
transformer primary are
considered to protect the
MLO panelboard.
However, the fuse amp
rating must adhere to NEC®
requirements and the fuse
type must adhere to the
panelboard SCCR
requirements
200A QSCP MLO
200A QSCP
Fused Main Disconnect
www.bussmann.com
19
Quik-Spec Coordination Panelboard (QSCP)
application note
Application Note 3148
Effective September 2015
Table 16. Sizing time-delay CUBEFuse for motors
Voltage
115Vac,
1-Phase
230Vac,
1-Phase
200Vac,
3-Phase
208Vac,
3-Phase
20
Time-delay CUBEFuse (A)
Time-delay CUBEFuse (A)
Motor
size (Hp)
Motor1
FLA
(Amps)
Optimal
protection
Code
max
Heavy
start
10
0.5
2.2
6
6
6
15
15
0.75
3.2
6
6
6
15
15
1
4.2
10
10
10
Motor
size (Hp)
Motor1
FLA
(Amps)
Optimal
protection
Code
max
Heavy
start
0.167
4.4
10
10
0.25
5.8
10
0.333
7.2
15
Voltage
0.5
9.8
15
20
20
1.5
6
10
15
15
0.75
13.8
25
25
30
2
6.8
15
15
15
1
16
25
30
35
3
9.6
15
20
20
1.5
20
30
35
45
5
15.2
25
30
30
2
24
40
45
50
7.5
22
35
40
45
3
34
50
60
70
10
28
45
50
60
230Vac,
3-Phase
5
56
90
100
N/A
15
42
70
80
90
0.167
2.2
6
6
6
20
54
90
100
N/A
0.25
2.9
6
6
6
0.5
1.1
3
3
3
0.333
3.6
6
10
10
0.75
1.6
3
3
3
0.5
4.9
10
10
10
1
2.1
6
6
6
0.75
6.9
15
15
15
1.5
3
6
6
6
1
8
15
15
17.5
2
3.4
6
6
6
1.5
10
15
20
20
3
4.8
10
10
10
2
12
20
25
25
5
7.6
15
15
15
3
17
25
30
35
7.5
11
17.5
20
20
5
28
45
50
60
10
14
25
25
30
7.5
40
60
70
90
15
21
35
40
45
10
50
80
90
N/A
20
27
40
50
60
0.5
2.5
6
6
6
25
34
60
60
70
0.75
3.7
6
10
10
30
40
60
70
90
1
4.8
10
10
10
40
52
80
100
N/A
1.5
6.9
15
15
15
50
65
100
N/A
N/A
0.9
3
3
3
460Vac,
3-Phase
7.8
15
15
17.5
0.5
3
11
17.5
20
20
0.75
1.3
3
3
3
5
17.5
30
35
35
1
1.7
3
3
3
7.5
25.3
40
45
50
1.5
2.4
6
6
6
10
32.2
50
60
70
2
2.7
6
6
6
15
48.3
80
90
100
3
3.9
6
10
10
2
20
62.1
100
N/A
N/A
5
6.1
10
15
15
0.5
2.4
6
6
6
7.5
9
15
20
20
0.75
3.5
6
10
10
10
11
17.5
20
20
575Vac,
3-Phase
1
4.6
10
10
10
15
17
30
30
35
1.5
6.6
10
15
15
20
22
35
40
45
2
7.5
15
15
15
25
27
45
50
60
3
10.6
17.5
20
20
30
32
50
60
70
5
16.7
25
30
35
40
41
70
80
90
7.5
24.2
40
45
50
50
52
80
100
N/A
10
30.8
50
60
60
60
62
100
N/A
N/A
15
46.2
70
90
100
20
59.4
90
N/A
N/A
www.bussmann.com
Note: Use code max column for low to moderate reverse/jog/plug applications.
Heavy start permitted only if code max does not allow motor start-up.
1. Based on motor FLA from NEC® Tables 430.248 and 430.250.
Quik-Spec Coordination Panelboard (QSCP)
application note
The QSCP and fast-acting CUBEFuse for protecting the
loadside of Uninterruptable Power Supplies (UPS)
Several industries, such as the petrochemical or pharmaceutical
industries, have a need to maintain power to critical, sensitive
loads making power system reliability an important design criteria.
These loads can include alarm and protection systems, sensors
and monitors, distributed control systems (DCS) circuits and
programmable logic controllers (PLC). These loads typically are fed
via an Uninterruptable Power Supply (UPS) system which presents
unique design considerations with regard to overcurrent protection.
These considerations include process load “holdup” times, UPS
dropout, transfer switch operation and selective coordination.
Application Note 3148
Effective September 2015
Figure 12. Holdup time with fast-acting CUBEFuse
Normal
Source
PWM (Pulse Width Modulated)
Short-Circuit Approximately
1.5 x FLC for ¼ Cycle
300-400A S.C.
UPS
30kVA
120V 1Ø
Alternate
Source
Static
Transfer
Switch
Holdup time
Holdup times for DCS, PLC and critical instrumentation loads are
typically 30ms or less. These loads are also typically low ampacity
circuits of 5 amps or less. See Figure 12.
However, given the low fault current from the UPS and/or small
conductor size for these loads, the operation time of the overcurrent
protective device under fault conditions can exceed the holdup time
of the critical loads.
Specifying overcurrent protective devices with fast fault clearing
time characteristics and sizing them according to manufacturer’s
specifications is essential. The objective is to have the overcurrent
protective device reliably clear fault conditions in times less than
the holdup time of the critical loads. In most cases, FCF fast-acting
CUBEFuses (blue label) can be sized small enough to ensure fault
operation times within the holdup time of the critical devices. Fastacting CUBEFuses are available in the small amp ratings (1, 3, 6, 10
and 15 amps) that can provide this necessary protection.
UPS Dropout and selective coordination
UPS dropout or damage occurs when a fault on one branch circuit
powering critical loads is not cleared quickly enough so it induces
voltage drop on the UPS output. See Figure 13. If the duration is
long enough, the induced voltage dropout can result in damage to
the UPS or cause some UPS systems to shut themselves down,
depending on the UPS type. When static transfer switches are
used, the dropout of the UPS results in higher fault currents on
these critical branch circuits. If the branch circuit overcurrent
protective devices do not selectively coordinate with panel feeder
device, loss of all critical UPS loads can result. Figure 13 shows a
fuse panel that utilizes fuses which only require a minimum of 2:1
ampacity ratio to selectively coordinate.
Holdup Times 0 VRMS
Duration Average
LPJ-200SP
FCF6RN
FCF Clearing Time
Set. ¼-½ Cycle
(4-8ms)
PLC
0-40ms
16ms
DCS
17-40ms
28ms
Critical
Instrumentation
0-30ms
15ms
FCF10RN
FCF15RN
QSCP Panelboard
Figure 13. Selective coordination with fast-acting CUBEFuse
Normal
Source
PWM (Pulse Width Modulated)
Short-Circuit Approximately
1.5 x FLC for ¼ Cycle
300-400A S.C.
• UPS Drops out
• Transfer switch operates
UPS
30kVA
120V 1Ø
Alternate
Source
Static
Transfer
Switch
LPJ-200SP
FCF6RN
FCF Clearing Time
Set. ¼-½ Cycle
(4-8ms)
FCF10RN
FCF Fuse is selectively
coordinated with 200A
upstream LPJ fuse
PLC
DCS
FCF15RN
Critical
Instrumentation
QSCP Panelboard
www.bussmann.com
21
Quik-Spec Coordination Panelboard (QSCP)
application note
Application Note 3148
Effective September 2015
QSCP and Surge Protective Devices
2014 NEC® 700.8 requires a listed SPD to be installed in or on all
emergency system switchboards and panelboards.
All configurations of the QSCP intended for installation on an AC
circuit can be ordered with an optional Surge Protective Device to
comply with this requirement.
The factory installed SPDs feature local, visual easyID™ status
indication and can be specified with a remote Form C contact
relay for integration into a monitoring system. The relay is rated
at 250Vac/0.5A and 250Vdc/0.1A, 125Vdc/0.2A, 75Vdc/0.5A to
accommodate many signaling needs.
Although a Type 1 SPD may be retrofitted and added externally
to meet the NEC® 2014 700.8 or other surge suppression needs,
it is recommended to factory order the SPD to assure correct
specification for the system voltage and type as well as proper
installation.
Available with
optional remote
signal Form C
contact
local visual
status
indication
High SCCR DIN-Rail Type 2 component assembly SPDs are factory
installed when the QSCP is ordered with a surge protective device.
If an SPD is required after the QSCP is installed (for surface mount
QSCPs only), Bussmann recommends installing the external-mount
Type 1 SurgePOD™ HEAVY DUTY (50kA surge current capacity
[Imax]), or the Type 1 or Type 2 BSPD (from 120kA up to 400kA surge
current capacity [Imax]) SPDs.
Installation of the externally-mounted SPD is facilitated by using a
CCPB branch disconnect to make the connections to the QSCP’s
internal busways. See suggested ampacities in Table A for the SPD
family product being installed.
Care should be taken to order the correct SurgePOD HEAVY DUTY
catalog number or specify the correct BSPD (from the catalog
number system) to match the electrical system type and voltage.
Table A - Circuit breaker and fused switch sizing guide
Suggested minimum
CCPB ampacity
SPD family
SurgePOD HEAVY DUTY (SPH)
60A
BSPD
100A
SurgePOD HEAVY DUTY is a Type 1 listed SPD with a 50kA surge
current capacity. Field installed device, does not ship with QSCP.
Must be ordered separately.
BSPD includes listed Type 1 or Type 2 SPDs (depending on the
configuration ordered) with surge current capacities from 120kA to
400kA and are configurable for Wye (120/208, 277/480, 600) and
Delta (240, 480, 600) systems. Field installed device, does not ship
with QSCP. Must be ordered separately.
22
www.bussmann.com
Quik-Spec Coordination Panelboard (QSCP)
application note
Application Note 3148
Effective September 2015
Reference materials
QSCP data sheet No. 1160
QSCP installation leaflet No. 3A1071
CCPB data sheet No. 1161
CCP data sheet No. 1157
Time-delay Class CF CUBEFuse data sheet No. 9000
Fast-acting Class CF CUBEFuse data sheet No. 2147
Time-delay Class J LPJ fuses, data sheet No. 1007
Fast-acting Class J JKS fuses, data sheet No. 1027
Selecting Protective Devices handbook No. 3002
Eaton molded case circuit breakers catalog No. CA08100005E
Eaton molded case circuit breakers and enclosures application data No. CA08104001E, sheet 27042
Eaton panelboards overview, No. CA08104001E, sheet 22002
North American UL Type 1, 2 and 3 Surge Protective Device application note No. 3193
SurgePOD HEAVY DUTY data sheet No. 2163
BSPD Surge Protective Devices data sheet No. 10209
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Quik-Spec Coordination Panelboard (QSCP)
application note
Application Note 3148
Effective September 2015
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Publication No. 3148 BU-SB14696
September 2015
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