rabtrfld
Member
- Location
- Milwaukee, Wisconsin
Sorry, I tried to post this before and it got screwed up.
Would anybody kindly critique my conclusions here... I have an old NEC but want to comply with 2008.
A 1ph, 240V, 40-amp UF supplies a detatched garage/workshop subpanel. It is fed from a 40A breaker in the main panel.
1) UF L1, L2 and N must be #8. (table 310-16, 60C column, UF, #8, 40A)
2) UF must have a #8 EGC. (formerly no EGC required in feeder? formerly #10 allowed by table 250-95?)
3) UF must be buried 24 inches under a lawn. (18 inches in PVC, table 300-5)
4) PVC at the ends of UF must extend down the full 24 inches .
5) The garage must have two ground rods 6 feet apart, with #8 GC. (table 250-94)
6) EGC and N must be separate at the subpanel.
7) The garage requires a disconnect.
8) The disco need not have OCP because of the 40A in the main panel, upstream of the feeder.
9) All receptacles, including ceiling receps for lights and door opener, must have GFCI. (210-8a2)
10) If a drop ceiling is added, the lamp cords/receps must not be above the ceiling.
11) Ground tails not required for yoke-grounded receps and covers in metal surface boxes grounded by EMT.
Also, one or more 240V twist-lock receps may be provided...
12) 240V receps do not require GFCI (not covered by 210-8a2).
13) 3-wire to a 240V recep counts as 2 wires (for derating) because it is a MWBC.
14) If #8 THHN is derated to 70% * 55A = 38.5A, then a 40-amp breaker is permitted.
15) A 240V 40A branch can be connected after the disco without a breaker because the feeder has 40A OCP.
16) A 240V 40A branch can not have a single 30A recep, but two receps are OK. (210-21b1)
Would anybody kindly critique my conclusions here... I have an old NEC but want to comply with 2008.
A 1ph, 240V, 40-amp UF supplies a detatched garage/workshop subpanel. It is fed from a 40A breaker in the main panel.
1) UF L1, L2 and N must be #8. (table 310-16, 60C column, UF, #8, 40A)
2) UF must have a #8 EGC. (formerly no EGC required in feeder? formerly #10 allowed by table 250-95?)
3) UF must be buried 24 inches under a lawn. (18 inches in PVC, table 300-5)
4) PVC at the ends of UF must extend down the full 24 inches .
5) The garage must have two ground rods 6 feet apart, with #8 GC. (table 250-94)
6) EGC and N must be separate at the subpanel.
7) The garage requires a disconnect.
8) The disco need not have OCP because of the 40A in the main panel, upstream of the feeder.
9) All receptacles, including ceiling receps for lights and door opener, must have GFCI. (210-8a2)
10) If a drop ceiling is added, the lamp cords/receps must not be above the ceiling.
11) Ground tails not required for yoke-grounded receps and covers in metal surface boxes grounded by EMT.
Also, one or more 240V twist-lock receps may be provided...
12) 240V receps do not require GFCI (not covered by 210-8a2).
13) 3-wire to a 240V recep counts as 2 wires (for derating) because it is a MWBC.
14) If #8 THHN is derated to 70% * 55A = 38.5A, then a 40-amp breaker is permitted.
15) A 240V 40A branch can be connected after the disco without a breaker because the feeder has 40A OCP.
16) A 240V 40A branch can not have a single 30A recep, but two receps are OK. (210-21b1)
