I ran 2" PVC into back corner of 200 Amp panel. The wires are single 4/0 conductors. It is a manufactures knockout, Square D QO 40 space panel. I believe wire bending space should fall under 312 .6(a), which is 4". I have 5 1/2", the inspector failed me and believes it should be 312.6(b). I'm trying to get him to understand, am I correct?
312.6
- Thread starter webelect
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Buck Parrish
Senior Member
- Location
- NC & IN
312.6 (b) 2 - provide the requirements for wire bending space where straight , or offset wiring is used at the terminals.
312.6 (b) 1 applies only to 90 degree bends.
312.6 (b) 1 applies only to 90 degree bends.
- Location
- Massachusetts
We have had long threads on this very issue. Many felt the fact it was 200 amp panel and had a factory 2" KO in the back meant we could ignore 312.6(B).
My opinion is it is up to the installer to make sure they can comply with the NEC. I fully understand that there are tens of thousands installations of 4/0 entering the rear of 200 amp panels .......... regardless it is still an NEC violation of 312.6(B).
My opinion is it is up to the installer to make sure they can comply with the NEC. I fully understand that there are tens of thousands installations of 4/0 entering the rear of 200 amp panels .......... regardless it is still an NEC violation of 312.6(B).
Buck Parrish
Senior Member
- Location
- NC & IN
A little, when table 312.6 (a) is used , the bending space is measured from where the wire leaves the terminal.
312.6 (b) it is measured in a direction perpindicular from the enclosures wall or barrier
Do these conductors enter their terminals via a 90 degree bend? if so
312.6 (B) (1) Conductors Not Entering or Leaving Opposite Wall. Table 312.6(A) shall apply where the conductor does not enter or leave the enclosure through the wall opposite its terminal.
HB explanatory print
"Section 312.6(B)(2) and Table 312.6(B) provide the requirements for wire-bending space where straight-in wiring or offset (double bends) is employed at terminals. Section 312.6(B)(1) applies only to 90 degree bends."
do these requirments apply to your installation??
hardworkingstiff
Senior Member
- Location
- Wilmington, NC
Reading the OP, it seems that table 312.6(B) is not applicable to this installation since the conductors do not enter from the opposite wall of the terminals.
- Location
- Massachusetts
I have never seen a panel that would not require a 90 degree bend in the conduit when the conductors enter the rear of the cabinet.
Bob, I guess I'm dense this morning (not unusual, I know), but if the 4/0 enters thru the back (opposite the removable cover) would 312.6(B)(1) not be applicable ? (therefore 4" would be compliant)
- Location
- Massachusetts
Aren't residential panels 3.5" deep?
augie <------walks away with head down in embarassment....:grin:
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
No they are 4" deep. You set the back of the panel even with the 2x4 and it sticks out 1/2" for sheetrock. Actually they are probably just shy of 4" with the sheet metal but wouldn't you measure from the connector end anyway. I can't remember the last time I entered the back of a panel but I always use those pvc chase fittings but that would still be less than 4" clear.
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- Location
- Massachusetts
I just measured the two I have and one is 3 1/2" - 3 5/8" deep, the other 3 3/4" deep exactly.
Many load centers have dimples protruding at the rear mounting holes so 4" inside is not possible within a typical resis wall.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
- Location
- Massachusetts
I was wondering about that as well. :-?
If I bring a 2" raceway into the back of a panel, once the locknut and bushing are in place I bet I am .75" to 1" into the panel. I would think the measurement should start from where the raceway ends.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I haven't seen many interior flush panels with dimples but that is a moot point. I agree with your post above
hardworkingstiff
Senior Member
- Location
- Wilmington, NC
- Location
- Massachusetts
No, it was about cpals post.
I did not have a good response to your post, I read those sections a bunch of times and find them more confusing then imaginable. :-?
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
In reading art. 312.6 I am not sure any of it relates to the wire entering the back of the box. It appears to me it is talking about the width of thebox not depth
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