Electrical Safety Through Design
Mersen EP
formerly – Ferraz Shawmut
Agenda
Who is Mersen?
Selective Coordination
– Code Requirements
– Coordination Made Easy
Mitigating Arc Flash Energy on Transformer Secondary
– 9F60HMH Series Approach
– Controllable Fuse Approach
Surge Protection
– Traditional Protection
– TPMOV Technology
Fusible Shunt Trip Panel
2
Company History
1880 - Thomas Edison issued first safety wire fuse patent
1885 - Shawmut Fuse Wire Company formed in Boston, MA
1887 – Research begins - How to encase wires safely. (Class H)
3
4
What is Selective Coordination?
Not This
5
Selective Coordination
What is Selective Coordination?
Localization of an overcurrent condition to restrict
outages, over the full range of available overcurrents
• Reduce downtime
• Prevent outages to critical circuits
• Improve safety
6
What is Selective Coordination?

But This
   
  
7
Why is it need?
Good Engineering Practice
– Reduce the blackouts to critical operations
– Reduce cost of maintenance
Critical power applications require it per the
National Electrical Code (NEC)
– Article 517.26
– Article 700.27
– Article 701.18
– Article 708.54
8
Critical Power per NEC 2014
Article 517
Health Care Facilities –
– 517.25 – The Essential Electrical System (essential for life)
requirements apply to clinics, medical and dental offices, nursing
homes, hospitals, etc.
– 517.26 - The Life safety branch of the Essential Electrical System
shall meet the requirements of Article 700 except as amended by
article 517
– *NEW* 517.30 (G) – Overcurrent protective devices serving the
essential electrical system shall be coordinated for the period of time
that a fault’s duration extends beyond 0.1 seconds
9
Critical Power per NEC 2014
Article 700
Emergency Systems –
– 700.2 – Emergency Systems. Systems legally required and classed
as emergency by municipal, state, federal, or other codes, or by any
governmental agency having jurisdiction. These systems are
intended to automatically supply illumination, power, or both, to
designated areas and equipment in the event of failure of the normal
supply or in the event of accident to elements of a system intended
to supply, distribute, and control power and illumination essential for
safety to human life.
10
Critical Power per NEC 2014
Article 700
Emergency Systems
– 700.28 – Selective Coordination.
Emergency systems overcurrent devices shall be selectively
coordinated with all supply side overcurrent protective
devices.
– New to 2014 Edition
– Selective coordination shall be selected by a licensed
professional engineer or other qualified persons engaged
primarily in the design, installation, or maintenance of
electrical systems. The selection shall be documented and
made available to those authorized to design, install,
inspect, maintain, and operate the system.
11
Critical Power per NEC 2014
Article 701
Legally Required Standby Systems
– 701.2 – Definition - FPN: Typically installed to serve loads such as HVAC,
communication, sewage disposal, lighting and industrial processes, that,
when stopped during any interruption of the normal electrical supply, could
create hazards or hamper rescue or fire-fighting operations.
– 701.27 – Selective Coordination Required
12
Critical Power per NEC 2014
Article 708
Critical Operations Power Systems
– Generally installed in vital infrastructure facilities, that, if destroyed or
incapacitated, would disrupt national security, the economy, public health
or safety. Systems include HVAC, fire alarm, security, communications and
signaling.
– 708.54 – Selective Coordination Required
13
Introducing MFCP!
•
Innovative branch circuit protection
•
20, 32 or 42 branch circuits
•
Only 3 branch fuses
• ATDR30, AJT60, AJT100
• Resettable overload protection
• Circuit Breaker trips on overloads
•
Standard of the shelf Class J and CC
fuses
•
Standard 20” wide
14
Mechanically Interlocked
Introducing MFCP!
Branch circuit
Protection
Circuit Breaker (OL)
•
•
•
•
•
•
•
•
•
•
•
•
•
15A – 1,2,3 pole
20A – 1,2,3 pole
25A – 1,2,3 pole
30A – 1,2,3 pole
35A – 1,2,3 pole
40A – 1,2,3 pole
45A – 1,2,3 pole
50A – 1,2,3 pole
60A – 1,2,3 pole
70A – 2,3 pole
80A – 2,3 pole
90A – 2,3 pole
100A – 2,3 pole
15
Ultra-Safe® Fuseholders (SC)
15A – 30A -> ATDR30
35A – 60A -> AJT60
70A – 100A -> AJT100
Insulated Busbar
T-C Curves
T-C Curves
18
Selective Coordination Panel
Selective Coordination Made
Easy
Easy to coordinate using fuse ratios
– 2:1 ratio with Amp-Trap 2000 fuses
19
Selective Coordination Made Easy
A4BQ1000

2:1 Ratio
With Amp-Trap 2000®
AJT200
AJT100
AJT350
A6D500R
   
MFCP
ATDR30
20
ATDR30
AJT60
AJT100
  
Introducing MFCP!
120/208V, 120/240V,
277/480V or 347/600V
MLO, Non-fused switch
with or without fuses
20, 32 or 42 branch
circuits
250A or 400A
Surface or flush-mount
enclosures
Feed-thru lugs
Surge Protection
21
Arc-Flash Hazard
The only protection between the load-side of the transformer
and the line-sides of the main breakers is the MV fuse or CB
on the line-side of the transformer.
22
Typical Substation Application
Paper Mill
(~ 30 : 1)
23
9F62DDD100
403 cal/cm2 @ 18”
Arc Fault Clearing
Time ~ 10 sec
24
Better Time Current Curves for Arc Faults
9F62DDD100
405 cal/cm2 @ 18”
Arc Fault Clearing
Time ~ 10 sec
9F60HMH100
13.7 cal/cm2 @ 18”
Arc Fault Clearing
Time ~ 300 ms
25
Solution:
Mersen’s Medium Voltage Controllable Fuse System
•
Reduces AF hazard to PPE
level 2 or less
•
Fits into existing fuse cabinets
•
Accepts inputs from standard
protective relays
•
Provides normal primary shortcircuit and overload protection
•
Costs a fraction of existing
mitigation gear
26
Mersen’s Medium Voltage Controllable Fuse System
Consists of 4 different part numbers:
A155CNF100 Fuse –
15.5 kV, 100A, 3 per system
CFAM-100 Actuator Module –
A155CNF100
Mounts to bottom of each of 3 fuses
CFIM-100 Interface Module –
Sends trip signal to CFAM
BATTCP1225 Battery –
CFIM100
One for each CFAM
CFAM100
27
BATTCP122
5
How does the MVCF work?
1. The AF detection system sends a trip signal via the relay to the CFIM
Interface Module. Both are located in the LV cabinet.
2. The CFIM immediately sends a fiber optic trip signal to the CFAM
Actuator Module attached to the fuse in the MV cabinet.
3. The CFAM emits a pulse that releases a switch mechanism inside the
fuse, disconnecting the direct path from the main fuse element.
4. The current is shunted to a small fuse element that opens in a
controlled manner.
28
Solution: Mersen’s Medium Voltage Controllable Fuse System
Features and Benefits
Fuses fit into existing space, with standard
clips – The only retrofitting that may be needed
is bolting in and/or repositioning new clips.
5.25”
2.74”
1.26”
29
The MVCF Reacts to Trigger Signal
Sensing is done by others:
Light sensors react to the flash,
and/or…
…current transformers react
to either absolute current
flow or the differential
Both sending their
signals to a relay
mounted in the LV
panel
and
others
Basler 851
30
SEL 751A
Eaton DigiTrip
How does the MVCF work?
Relay
Fuse A155CNF100
Input From
AF Sensors
Main Fuse
Element
Made by Others
Single-use
Interface Module CFIM100
Normally Closed
Controlled
Fuse Element
Switch
Actuator Module
CFAM100
Fiber Optic Cable
31
Controllable Fuse Approach
Commutated Fuse
Protection System
32
How does the MVCF work?
33
34
Why Surge Protection? Utility Switching
35
SPD Operation
Load 1
Load 2
Load 3
MOV/SPD tries to:
1.) Send surge away (to ground)
2.) Acts as a momentary ‘short circuit’
‘short circuit’ ≈ voltage equalization ≈ no overvoltage ≈ protected load
36
Traditional MOV Technology
37
How to Protect: TPMOV® Technology
Thermally Protected Metal Oxide Varistor
by
Patented Technology by Mersen
The first MOV technology to pass UL1449 4th Edition
38
TPMOV Technology – Fail Safe Surge Products
39
40
41
42
43
44
45
46
Fusible Shunt Trip
Disconnect Switches
Elevator Switches
ASME/ANSI A17.1- 2000 - Safety Code for
Elevators and Escalators calls for remote,
automatic disconnection of the main line
power prior to the application of water in
elevator and/or other sprinkler system
applications…
47
Elevator Switches
Specifics
A fusible switch (30,60,100,200,400A)
used with AJT fuses (fuses ordered
separately).
Switch is equipped with a tripping
mechanism operated by energizing a
coil (solenoid device), called a shunt
trip.
There is a control system for tripping
coordinated with fire safety interface.
Switch and system are in an enclosure,
and are mounted in or near the elevator
machinery room.
48
Elevator Switch Construction
control transformer
and fuse protection
Grounding lug
Neutral lug
pilot
light
shunt-trip
switch
key to
test
switch
Auxiliary
contacts
class J fuses
(purchased
separately)
and block
door
interlocking
handle
door interlock
relays
NEMA1 enclosure
49
wiring diagram
terminal
blocks
Simple Ordering
50
Thank You. Any Questions?
Amp-Trap 2000®
51