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I N S TA L L AT I O N , O P ER AT I O N S A N D M A I N T EN A N C E M A N UA L
11
Torque specifications
Switchboards are furnished with medium carbon
steel hardware with the tensile strengths listed
in Table 1. Similar hardware must be used for any
additional bolting. For both copper and aluminum
connections, use a torque wrench when tightening
to the nominal values given.
Use flat and lock washers for all connections.
Do not place washers under the heads of
carriage bolts.
For equipment wiring terminal torque values see
Table 3. For device terminal torque values reference
the appropriate device installation guide.
Electrical clearances
Maintain the minimum clearances listed in Table
2 except at terminals of circuit breakers and
switches. A through-air spacing of not less than ½
inch is acceptable at a circuit breaker or a switch,
other than a snap switch, and between grounded
dead metal and the insulated neutral of a 277/480
VAC three-phase, four-wire panelboard or
switchboard. Where neutral-to-phase is involved,
spacing may be based on the normal voltage
between them.
a
A through air spacing of not less than 12.5 mm (½ inch) may be used:
1. At a circuit breaker or a switch, other than a snap switch;
2. Between uninsulated live parts of a meter mounting base and grounded metal; and
3. Between grounded metal and the neutral of a 3-phase, 4-wire switchboard.
Note 1 – Exceptions to these minimum spacings covered in UL891 8.1.16.2-8.1.16.6.
Note 2 – The SI units are minimum values and are not a direct conversion from the coresponding values in inches.
Reference: NMX-J-118/2-ANCE-2019 CSA C22.2 No. 244:19, UL891
Bolt size [in]
Tensile strength [psi]
Torque [lb-ft]
¼-20
120.000
4
5/16-18
120.000
9
3/8-16
120.000
16
½-13
60.000
39
½-13 with 21/4
Belleville Washer
60.000
35
5/8-16
60.000
80
Hardware type
Hardware
size
Cable size
[AWG/MCM]
Torque
[lb-in]
Slot ≤ 1/4"
#8
18 - 8
12
#10 and
larger
18 - 10
20
8
25
6 - 3
35
2
40
Slot ≥ 1/4"
#10 and
larger
18 - 10
35
8
40
6 - 4
45
50
Hex,
Hex with slot
#10 and
larger
18 - 8
75
6 - 4
110
3 - 1
150
1/0 - 2/0
180
3/0 - 4/0
250
250 - 400
325
500 - 750
375
500
Internal hex size
3/16
-
120
1/4
200
5/16
275
3/8
375
1/2
500
Voltage involved
Minimum spacing through air
and over surface between live
parts and grounded metal
Greater
than
Maximum
Through air
Over surface
mm
(in)
mm
(in)
0
130
12.5
(½)
19.0
(¾)
12.5
½
130
250
19
(¾)
31
(1–¼)
12.5
½
250
600
25
(1)
50
(2)
25a
1a
600
1000
25
(1)
50
(2)
25a
1a
—
Table 1: Tightening torques for supplied hardware
—
Table 3: Equipment wiring terminal torque values
—
Table 2: Minimum clearances for live parts
Neutral-to-ground spacing should be based on the
same spacing required for the other conductors.
A through-air spacing of not less than ½ inch is
acceptable at a circuit breaker or a switch, other
than a snap switch, and between grounded dead
metal and the insulated neutral of a 277/480 VAC
three-phase, four-wire panelboard or switchboard.
Where neutral-to-phase is involved, spacing may
be based on the normal voltage between them.
Neutral-to-ground spacing should be based on the
same spacing required for the other conductors.
Summary of Contents for ABB ReliaGear SB
Page 1: ...INSTALLATION OPER ATIONS AND MAINTENANCE MANUAL ReliaGear SB Switchboards ...
Page 2: ......
Page 30: ...30 RELIAGEAR SB SWITCHBOARDS ...
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