Do’s and don'ts of connection systems
Are there any options when the clearance and creepage distances are not sufficient
for UL 1059?
Speaker: Wolfgang Sichmann, Product Manager PCB Plug-In Connectors, Weidmüller Interface GmbH &Co. KG
Contents
- Introduction
- UL device approvals. Listing
- UL component approvals, UL 1059
- UL 1059 application groups for Terminal Blocks and Connectors
- UL 1059 case study of clearance and creepage problem
- Option to clear the 600 V barrier via UL 508 / UL840 device approval
-
For connectors soldered on the printed circuit board
-
for PCB terminals
-
Pollution degree / overvoltage category / clearance and creepage distances
Pollution degree / overvoltage category / equivalents of clearance and creepage distances
- Wire-end ferrules for the American market
- Multiple wire connection at one pole
POWER FORTONIC FORUM 19 settembre 2013
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 2
Introduction
The trend for increasingly compact and powerful devices is generally met with higher voltages.
While maintaining the same power level, current and connection cross-sections are kept within
reasonable limits, which impacts positively on the size of the devices. However, higher voltages
increase the requirements for clearance and creepage distances. Connection systems are
inevitably following the trend for smaller sizes, which poses a challenge in relation to UL 1059 in
particular. The UL 1059's strict regulations for field wiring components are absolutely justified, and
illustrate the high demands on usage and handling. The aim here is to avoid mistakes in the field,
or if mistakes have been made, to minimise the resulting damage.
For the part of the connection system that is installed in the device in a secure manufacturing
process, there is an option of approval with reduced clearance and creepage distances as part of
the device (factory wiring). However, this means that the UL 1059 regulations also have to be
observed in full for everything that is wired up or get connected in the field.
With regard to the field connection, further differences to European usage and handling must also
be taken into account. Topics such as multiple wire connections and wire-end ferrules underline the
convergence but it also shows the differences between Europe and the US.
POWER FORTONIC FORUM 19 settembre 2013
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 3
Difference between field and factory wiring
Field wiring
 Plug or terminal with cable or single wires to
connect field components
Factory wiring
 Includes, for example, a plug-in connector,
which is installed in the device during
manufacturing in line with the applicable
manufacturing guidelines.
 Example:
 By means of fastening and wiring
 By means on soldering to the PCB
Field wiring = UL 1059 / factory wiring = UL 508(C)
POWER FORTONIC FORUM 19 settembre 2013
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 9
UL 1059 application groups for terminals and plug-in connectors
 Use Group A: service devices
 Control and operating consoles
Control and monitoring systems
 Use Group B: commercial appliances
 Cable-connected devices
which are not permanently installed
 Use Group C: Industrial general
 All devices and systems for industrial
applications
 Use Group D: Industrial limited ratings
 All devices and systems for industrial
applications with
limited current data
 Use Group E: 601 – 1,000 (1,500) volt
 Connection systems in the range of
601 to 1,500 volts
POWER FORTONIC FORUM 19 settembre 2013
back
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 10
UL 1059: clearance and creepage distances
Table 8.1
8.5 Limited ratings
The spacings specified in item D of Table 8.1 are applicable to a terminal block for use only in or
with industrial control equipment where the load on any single circuit of the terminal block does not
exceed 15 A at 51 – 150 V, 10 A at 151 – 300 V, 5 A at 301 – 600 V,
back
or the maximum ampere rating, whichever is less.
POWER FORTONIC FORUM 19 settembre 2013
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 11
Case 1: selection of a plug-in connector with corresponding
requirements
Example
Component for field wiring
Requirement up to 600 V
 Class C industrial general
 301 – 600 V
 35 A max.
UL 1059 rating data
Rated voltage (use group B)
600 V
Rated current (use group B)
35 A
Rated voltage (use group C)
600 V
Rated current (use group C)
35 A
Rated voltage (use group D)
Rated current (use group D)
600 V
5A
Result:
 The field wiring component meets
ok. the requirements of UL 1059.
Back to UL 1059
POWER FORTONIC FORUM 19 settembre 2013
back
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 12
Case 2: Excerpt from catalogue or data sheet
Example:
Through air distance
7.62 mm
(0.3 inch)
Requirement up to 600 V
 Class C industrial general
 301 – 600 V
 35 A max.
6.9 mm
(0.272 inch)
Result:
 The requirements are
not met for UL 1059 at 301 – 600 V
but
are met for UL 1059 at 151 – 300 V.
UL 1059 rating data
Rated voltage (use group B)
300 V
Rated current (use group B)
35 A
Rated voltage (use group C)
300 V
Rated current (use group C)
35 A
Rated voltage (use group D)
Rated current (use group D)
600 V
5A
To UL 1059
POWER FORTONIC FORUM 19 settembre 2013
?
 Acc. to Table 8.1, UL 1059
for 301-600V we need a:
 Clearance of 9.5 mm
 Creepage 12.7 mm
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
back
Slide 13
But the requirement is between 301 – 600 volts
?? What now ??
The component assembled on
the PCB
 can be jointly approved under device
approval 508 (C)
Factory wiring
 if the component fulfils the
factory wiring criteria!
Field wiring
The counter part
(field wiring component)
 must be approved under UL 1059!
POWER FORTONIC FORUM 19 settembre 2013
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 14
Option of device approval
via UL 508 / UL 840
for plug-in connectors on the PCB
Guide to
device approval via
UL 508 and UL 840
Component type test clearance and creepage distance
No
UL 1059
Terminal
Blocks
Yes
UL 508 / 508C
UL 840
Yes
exception
No
Standard
Requirements
Alternative for PCB Components
Industrial Controls /
Power Conversion
Equipment
Yes
UL 508A
UL 840
exception
No
Standard
Requirements
Industrial
Control Panels
Yes
Yes
UL 2011
UL 840
Yes
exception
No
Standard
Requirements
Factory
Automation
Equipment
Yes
NEC - National Electrical Code
POWER FORTONIC FORUM 19 settembre 2013
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 16
Step 1: clearance
UL 840
600 V  factory wiring (PCB connectors)
• UL 508 C Table 36.5 clearance distance = UL 1059
• Therfore with UL 508 C exception 36.9.1
via UL 840 insulation coordination
for the clearance distance
Pollution degree
UL 840 – 9.3
Overvoltage Category
UL 840 – Table 8.1
component type test
clearance - connector
UL 840 – Table 8.1
min. clearance - UL
No
larger pitch required
POWER FORTONIC FORUM 19 settembre 2013
≤
Yes
Clearance passed
according to UL840
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 17
Step 1/1:
Finding the clearance distance
Weidmüller type test:
1.1.2 Lab report,
clearance and creepage distance acc. to UL 1059
clearance
!
Acc. to UL 1059 (600 V class C) or UL 508 (C)
min. clearance = 9.5 mm
min. creepage = 12.7 mm
POWER FORTONIC FORUM 19 settembre 2013
to UL 1059
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
back
Slide 18
Step 1/2:
Finding the pollution degree
UL 840 - 9.3 Pollution Degree
Pollution degrees based on the presence of contaminants and possibility of
condensation or moisture at the creepage distance are as follows:
 Pollution Degree 1:
No pollution or only dry, nonconductive pollution. The pollution has no influence.
 Pollution Degree 2:
Normally, only nonconductive pollution. However, a temporary conductivity caused by condensation may be expected.
 Pollution Degree 3:
Conductive pollution, or dry, nonconductive pollution that becomes conductive due to condensation that is expected.
 Pollution Degree 4:
Pollution that generates persistent conductivity through conductive dust or rain and snow.
back
POWER FORTONIC FORUM 19 settembre 2013
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 19
power supply
Overvoltage category
Potential isolation
Distribution Level
Load Level
Overvoltage category IV
Primary supply level
Overvolt. category III
Distribution level
Overvolt. category II
Load level
Overvolt. category I
Signal level
Take lightning surge into account
Lightning surges do
not have to be taken
into account
Take into account
overvoltage caused
by switching
operations e.g.
household devices
No overvoltage
taken into account
Primary Supply Level
Permanent installation
back
POWER FORTONIC FORUM 19 settembre 2013
Signal Level
Mainly operations
with low voltages
e.g. small electric devices
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 20
Step 1/3: UL 840 Table 8.1 minimum clearance
UL 840 Section 8.9
Clearances selected and
measured in accordance
with the dimensions in
Table 8.1 do not require
testing.
To type test
to overvoltage
to pollution
POWER FORTONIC FORUM 19 settembre 2013
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
back
Slide 21
Step 2: Creepage
UL 840 – 600 V  factory wiring (PCB connectors)
CTI of material
(catalogue)
Material Group
UL840
(catalogue)
Pollution degree
UL840 – 9.3
600 V
Operating Voltage
Table 9.1 – UL840
min. creepage distance - UL
No
larger pitch required
POWER FORTONIC FORUM 19 settembre 2013
≤
component type test
creepage distance -connector
Yes
Creepage distance
according to UL840
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 22
Step 2/1:
Finding the creepage distance
Weidmüller type test:
1.1.2 Lab report,
clearance and creepage distance acc. to UL 1059
creepage
!
Acc. to UL 1059 (600 V class C) or UL 508 (C)
min. clearance = 9.5 mm
min. creepage = 12.7 mm
POWER FORTONIC FORUM 19 settembre 2013
to UL1059
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
back
Slide 23
Step 2/2:
UL 840 Table 9.3
Finding the pollution degree
UL 840 section 9.3 Pollution Degree
Pollution degrees based on the presence of contaminants and possibility of
condensation or moisture at the creepage distance are as follows:
 Pollution Degree 1:
No pollution or only dry, nonconductive pollution. The pollution has no influence.
 Pollution Degree 2:
Normally, only nonconductive pollution. However, a temporary conductivity caused by condensation may be expected.
 Pollution Degree 3:
Conductive pollution, or dry, nonconductive pollution that becomes conductive due to condensation that is expected.
 Pollution Degree 4:
Pollution that generates persistent conductivity through conductive dust or rain and snow.
back to creepage table
back
POWER FORTONIC FORUM 19 settembre 2013
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 24
Step 2/3:
UL 840 Table 9.1
minimum creepage
2
Material groups
3
Link to pollution degree info
Group
CTI
I
>600
II
400 – 599
IIIa
175 – 399
IIIb
100 – 174
CTI of material
Creepage acc. to type test = 9.66 mm
POWER FORTONIC FORUM 19 settembre 2013
Creepage can not be less then over air distance ( 5.5mm) 6.9mm!
PBT
200
Wemid
600
LCP
175
to type test 1/2
to pollution degree 2/2
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
back
Slide 25
Summary of the solution for the PCB part
of the connector using UL 508(C) and UL 840
New clearance distance 5.5 mm
acc. to 508(C) & UL 840
Clearance
O.K.
No
Yes
UL 508 (C)
Clearance distance
according to UL840
exception
UL 840
distance
New Creepage
creepage 3.2
mm
acc.to 508(C) & UL 840
No
exception
UL 840
O.K.
Yes
UL 508A
No
exception
UL 840
UL 2011
Yes
NEC
National Electrical Code
Creepage distance
according to UL840
POWER FORTONIC FORUM 19 settembre 2013
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 26
The demand for increasingly compact connection systems makes this
procedure necessary.
job done!
Factory wiring
600 V via
UL 508 & UL 840
Field wiring
600V UL 1059 class C
POWER FORTONIC FORUM 19 settembre 2013
PCB part:
Approval together with
device approval UL 508(C)
und UL 840. The component
meets the clearance and
creepage requirements for
600 Volt !
Field part:
No further action possible
or necessary.
The component meets the
requirements of
UL 1059 for 600 V!
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 27
Option of device approval
via UL 508 / UL 840
for PCB terminals
Guide to
device approval via
UL 508 and UL 840
Component type test clearance and creepage distance
No
UL 1059
Terminal
Blocks
Yes
UL 508 / 508C
UL 840
Yes
exception
No
Standard
Requirements
Alternative for PCB Components
Industrial Controls /
Power Conversion
Equipment
Yes
UL 508A
UL 840
exception
No
Standard
Requirements
Industrial
Control Panels
Yes
Yes
UL 2011
UL 840
Yes
exception
No
Standard
Requirements
Factory
Automation
Equipment
Yes
NEC - National Electrical Code
POWER FORTONIC FORUM 19 settembre 2013
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 29
Step 1: Clearance A (equivalency)
UL 840
600 V 9.5 mm clearance distance as per Table 7.1
• UL 508 C Table 36.5 clearance = UL 1059
• Therefore with UL 508C exception 36.9.3
• protection against stray strands (splicing)
+
UL 50 8C 36.9.4 exception via
• UL 840 clearance A (equivalency)
Table 7.1
UL 840 – Table 7.1
Clearance A (Equivalency)
No
larger pitch required
POWER FORTONIC FORUM 19 settembre 2013
HV
test positive
Yes
Clearance
according to UL840
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
back
Slide 30
Step 1/1:
Finding the clearance distance
Weidmüller type test:
1.1.2 Clearance and creepage distance
acc. to UL 1059
clearance
!
Acc. to UL 1059 (600 V class C) or UL 508 (C)
min. clearance = 9.5 mm
min. creepage = 12.7 mm
POWER FORTONIC FORUM 19 settembre 2013
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Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 31
Step 1/2: (replacement test for shorter clearance distances)
Finding the test voltage
UL 840
7 Clearance A (Equivalency)
7.1 Other than as noted in 1.6,
the requirements of this section
may be used to evaluate
clearances less than those
specified for the end product
while maintaining the same
overvoltage withstand capability
for the equipment.
7.2 A clearance, less than the
specified minimum through air
spacing, in the product standard,
may be suitable if acceptable
results are obtained when tested
in accordance with Section 14,
Dielectric Voltage-Withstand
Tests, using a voltage with a
value in accordance with
Table 7.1…
back
POWER FORTONIC FORUM 19 settembre 2013
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 32
Step 2: Creepage
UL 840 – 600 V  (PCB terminals)
CTI of material
(catalogue)
Material group
UL 840
(catalogue)
Pollution degree
UL 840 – 9.3
600 V
Operating voltage
Table 9.1 – UL 840
min. creepage distance - UL
No
larger pitch required
POWER FORTONIC FORUM 19 settembre 2013
≤
component type test
creepage distance connector
Yes
Creepage distance
according to UL 840
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 33
Step 2/1:
Finding the creepage distance
Weidmüller type test:
1.1.2 Clearance and creepage distance
acc. to UL 1059
creepage
!
Acc. to UL 1059 (600 V class C) or UL 508 (C)
min. clearance = 9.5 mm
min. creepage = 12.7 mm
POWER FORTONIC FORUM 19 settembre 2013
Back to table 9.1 2/4
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
back
Slide 34
Step 2/2:
Finding the pollution degree
UL 840 - 9.3 Pollution Degree
Pollution degrees based on the presence of contaminants and possibility of
condensation or moisture at the creepage distance are as follows:
 Pollution Degree 1:
No pollution or only dry, nonconductive pollution. The pollution has no influence.
 Pollution Degree 2:
Normally, only nonconductive pollution. However, a temporary conductivity caused by condensation may be expected.
 Pollution Degree 3:
Conductive pollution, or dry, nonconductive pollution that becomes conductive due to condensation that is expected.
 Pollution Degree 4:
Pollution that generates persistent conductivity through conductive dust or rain and snow.
Back to table 9.1 2/4
POWER FORTONIC FORUM 19 settembre 2013
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
back
Slide 35
Step 2/3:
UL 840 Table 9.1
minimum creepage
2
Material groups
3
Link to pollution degree info
Group
CTI
I
>600
II
400 – 599
IIIa
175 – 399
IIIb
100 – 174
CTI of material
Creepage acc. to type test = 12,6 mm
POWER FORTONIC FORUM 19 settembre 2013
Creepage can not be less then over air distance (= 8.8mm)!
PBT
200
Wemid
600
LCP
175
to pollution degr.
to type test
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
back
Slide 36
Summary:
Possible dimensioning of clearance and creepage distances for UL 600 V
Product standards
UL 1059 requirements
clearance / creepage
> 9.5 mm
for 600 V
Alternative assessment
(insulation coordination)
Device standards
UL 1059
UL 840
UL 508 (C)
OK
600 V
OK for 600
> 12.7 mm
Table 9.1 UL 840
Material Group I ( Wemid )
6.9 mm from lab. rep.
> 6.4 mm
Pollution degree
OK for 300 V
for 300 V
> 9.5 mm
Through air
9.66 mm from lab. rep.
Creepage
> 6.4mm
for 300 V
> 9.5 mm
8.8 mm from lab. rep.
OK for 300 V
+
12.6 mm from lab. rep.
POWER FORTONIC FORUM 19 settembre 2013
Protection
against
stray
strands
+
2
| 3
5.5 mm | 5.5 mm
requ.
(3.2) 5.5mm | 8.0 mm
requ.
OK
600 V
requ.
OK
600 V
Surge voltage test 10.7 kV
no clearance measurement
Creepage
(3.2) 8.8 mm | 8.8 mm
Acc. to UL 1059 (600 V Class C) or UL 5.08 (C)
min. clearance = 9.5 mm
min. creepage = 12.7 mm
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 37
Wire-end ferrules for the American market
 Tools
- The ferrules may only be used together with
tested tools
 Twin wire-end ferrules
- As they have not been approved, the use of
twin wire-end ferrules are not allowed in either
control or power circuits
 Wire-end ferrules for power circuits
- All wire-end ferrules must be approved by UL
- Can be used in field and factory wiring
POWER FORTONIC FORUM 19 settembre 2013
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 38
Wire-end ferrules for the American market
 Wire-end ferrules in control circuits
- Under factory wiring conditions and < AWG 14,
wire-end ferrules may also be used without approval.
 For UL 508A
- There is a UL guideline that permits the usage in
control and power circuits under factory wiring
conditions
 UL 508
- Usage as in UL 508A is planned
 UL 508C
- No approval is planned for this at the moment
POWER FORTONIC FORUM 19 settembre 2013
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 39
Multiple wire connection at one pole
 Multiple wire connection
- the combination of the used connection system with the used
conductors must always to be tested by UL
 Test
- UL will test each combination with the full testing programme
 Wire cross-section and conductor type
- Only conductors with the same cross-section and of the same
type may be used
 Number of conductors per connection
- The number of conductors approved by UL is indicated in the
designation in brace before the wire cross-section
e.g.: (4) AWG 12 str
- This really does mean that only four conductors may be used.
Two, three or more than four conductors are not permitted.
POWER FORTONIC FORUM 19 settembre 2013
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 40
Any questions?
Thank you!
POWER FORTONIC FORUM 19 settembre 2013
Wolfgang Sichmann Weidmüller Interface GmbH & Co. KG
Slide 41