![](http://datasheet.mmic.net.cn/180000/PDB280-1_datasheet_11344270/PDB280-1_22.png)
For more information on this see section Conductor &
Terminations – Application Considerations in the Cooper
Bussmann publication SPD – Selecting Protective Devices on
www.cooperbussmann.com
UL 508A Industrial Control Panels Conductors for
Internal Wiring: Copper conductors only. Conductors are
sized based on either the 60°C or 75°C allowable conductor
ampacities from UL508A, Table 28.1 (following). The 75°C
ampacities can only be used if the termination temperature
ratings at both ends of the conductor are rated 75°C or
60°C/75°C. In addition, the conductor insulation is required
to be 90°C or higher temperature rated even though the
ampacity is based on 60°C or 75°C (UL508A, 29.2.1 &
29.6.1(b)).
HVAC Equipment (UL1995):
The electrical panel is required to be marked with the
assembly SCCR per NEC 440.4(B). The larger spacing that
is mandated in UL508A is not present in UL1995. If the
control panel for the HVAC equipment is a listed UL508A
panel, then the larger UL508A spacing is required.
Power Distribution Block Application UL 1995
Example
PDB in 480V UL 1995 HVAC Equipment must have spacing of 3/8
through air and 1/2 over surface. PDBs listed to UL 1953 meet this spacing
as well as most terminal blocks recognized to UL 1059.
Form No. PDB
Page 22 of 23
Data Sheet #1049
07-05-07
BU-SB07255
Application Notes
UL508A, Table 28.1 (Partial)
Wire size
60C (140F)
75C (167F)
AWG
(mm
2)
Copper
14
(2.1)
15
12
(3.3)
20
10
(5.3)
30
8
(8.4)
40
50
6
(13.3)
55
65
4
(21.2)
70
85
3
(26.7)
85
100
2
(33.6)
95
115
1
(42.4)
110
130
1/0
(53.5)
–
2/0
(67.4)
–
175
3/0
(85.0)
–
200
4/0
(107.2)
–
230
250 kcmil
(127)
–
255
300
(152)
–
285
350
(177)
–
310
400
(203)
–
335
500
(253)
–
380
600
(304)
–
420
700
(355)
–
460
750
(380)
–
475
800
(405)
–
490
900
(456)
–
520
1000
(506)
–
545
1250
(633)
–
590
1500
(760)
–
625
1750
(887)
–
650
2000
(1013)
–
665
NOTES
1 For multiple-conductors of the same size (1/0 AWG or larger) at a terminal, the
ampacity is equal to the value in this table for that conductor multiplied by the
number of conductors that the terminal is able to accommodate.