Selection Table for SCCR Power Distribution Blocks and
Terminal Blocks
Short-Circuit Current Rated Power Distribution
Blocks
Cooper Bussmann offers three distinctly different styles of
short-circuit current rated power distribution blocks (PDBs)
and terminal blocks (TBs) to match different application
needs. The differences are whether the power
distribution blocks are enclosed or not, and whether they are
UL1953 Listed PDBs or UL1059 Recognized TBs, which have
different minimum spacing requirements. The table on this
page can assist in the selection of the right series for your
application requirements.
Why these are important?
Assembly short-circuit current ratings (SCCRs) are now
required in the 2005 NEC
®
and UL508A Listed Industrial
Control Panels. Marking the SCCR on Industrial Control
Panels (NEC
®
409.110), Industrial Machinery Electrical
Panels (NEC
®
670.3(A)), and HVAC equipment (NEC
®
440.4(B)) is now required by the National Electrical Code.
PDBs or TBs not marked with a SCCR are typically one of
the weakest links and may limit an assembly to no more than
10kA SCCR. The PDBFS and PDB Series have increased
spacing required where used in feeder circuits in equipment
listed to UL508A (UL1059 TBs must be evaluated for proper
spacings). Also, for building wiring systems, the PDBFS
Series and PDB Series power distribution blocks can be used
to meet the new 2005 NEC
®
requirements in section
376.56(B) for PDBs in wireways.
More application info rmation on pages 19-23.
Selection Table
Product
Catalog
Page
High
Enclosed SCCR*
Spacing**
1” Air
2” Surface
Industrial
Control
Panels
UL 508A
Branch
Circuit
Yes
Industrial
Control
Panels
UL 508A
Feeder
Circuit
Yes
HVAC
UL
1995
Wireways
NEC
®
376.56(B)
(Requires
UL 1953)
Yes
Yes
w/optional
cover
No
UL
Series PDBFS
3
UL 1953 Listed
Power Distribution Blocks
UL 1953 Listed
Power Distribution Blocks
UL 1059 Recognized
Terminal Blocks
Yes
†
Yes
Yes
Yes
Series PDB
Series
16XXX
NDN63-WH-UL,
NDN111-WH-UL,
14002-3-UL,
TB300-03SP-UL
9
No***
Yes
Yes
Yes
Yes
Yes
13
No***
Yes
No****
Yes
No****
Yes
16
UL 1059 Recognized
Terminal Blocks
No
Yes
No
Yes
No
Yes
No
† IP-20 finger-safe under specific conditions, see datasheet page 8.
*When protected by proper fuse class with maximum ampere rating specified or smaller.
** See
PDB Spacing Requirements for Equipment
table below.
***Optional covers are available. Not IP-20, but provide a safety benefit.
****No, except: Yes, if single pole units installed with proper spacings.
PDB & TB Minimum Spacing
Requirements for Equipment
UL Standard
Spacing between
Spacing between
live parts of
live parts and
opposite polarity
grounded parts
or enclosure
Through air Over surface
@600V
@600V
@600V
Series PDBFS
Series PDB
508A Feeder
Circuits
508A Branch
Circuits
1995 HVAC
1˝
3
2˝
1
1˝
1
⁄
8
˝
3
⁄
8
˝
⁄
2
˝
1
⁄
2
˝
⁄
2
˝
1
⁄
2
˝
Magnum Terminal Blocks
Series 162 and 163
Note: Refer to Specific UL standards for complete spacing details.
1011
SB-BU09622
Page 2 of 23
Data Sheet 1049
COOPER [ COOPER BUSSMANN, INC. ]
