splices in distribution panels

Status
Not open for further replies.
Re: splices in distribution panels

312.8 permits splices in enclosures, as long as the splices do not fill the wiring space more than 75%.
Jim says he sees this seldom, I see it quite a bit, even without the splices... NY must have smaller gutter space panels ;)
 
Re: splices in distribution panels

Originally posted by pierre:
Jim says he sees this seldom, I see it quite a bit, even without the splices... NY must have smaller gutter space panels ;)
Click to expand...
Pierre I do not think it is physically possible to fill a cross section of the panel beyond 75% fill with splices.

Take a look at a raceway that is 40% filled, it is quite full.

An interesting thing that was recently pointed out to me is that 312.8 only applies to conductors that are passing through the enclosure.
 
Re: splices in distribution panels

He always makes comments without any substance, the entertainment value comes when he try's to crawfish his way out of what he originally says.
 
Re: splices in distribution panels

312.8 Enclosures for Switches or Overcurrent Devices.
Enclosures for switches or overcurrent devices shall not be used as junction boxes, auxiliary gutters, or raceways for conductors feeding through or tapping off to other switches or overcurrent devices, unless adequate space for this purpose is provided. The conductors shall not fill the wiring space at any cross section to more than 40 percent of the cross-sectional area of the space, and the conductors, splices, and taps shall not fill the wiring space at any cross section to more than 75 percent of the cross-sectional area of that space.
Click to expand...
I had not noticed this until someone pointed it out to me the other day.
 
Re: splices in distribution panels

Bob
I find it hard to believe you have not come across any panels that are so packed. I have some photos, I will locate them and email them to you so you can post them.
 
Re: splices in distribution panels

Pierre,
Did you actually count the wires and do the calculations? I agree with Bob, that it would almost physically impossible to exceed the 75% permitted fill for splices. I too have seen pictures of "filled" wireway space, but doubt that it exceeded the 40% fill for conductors. A 3"x3" wireway will hold 270 #12 THHNs at 40% fill. Many panel wireways are of this size. Even if the panel is 3" deep and the wireway is only 1" wide, you would be permitted to have 90 #12s at any given point along the wireway space.
Don
edited to add calculations.

[ December 26, 2005, 02:39 PM: Message edited by: don_resqcapt19 ]
 
Re: splices in distribution panels

Lets say you have a very modest gutter space of 3" W 2.5" deep that is 7.5 sq in.

At 40% fill that is 3 sq in or 309 - 14 AWG THHNs. :eek:
 
Re: splices in distribution panels

While we are at this I do have a question.

Do we have to count conductors in this calculation that are not feeding through or tapping off to other switches or overcurrent devices?

In other words are the incoming conductors from the cables or raceways that run directly to overcurrent devices in the same enclosure even covered by 312.8?
 
Re: splices in distribution panels

Originally posted by iwire:
While we are at this I do have a question.

Do we have to count conductors in this calculation that are not feeding through or tapping off to other switches or overcurrent devices?
Click to expand...
I read this to say that if the conductors terminate on a breaker in this same panel, this section does not apply.

Feeding them through would probably be Ch........ oops never gonna say that word again... :)

Actually I have done just that before where panels were all piped into the same troff and there were no available breakers in the panel where the conduit was already so conviently run to.
 
Status
Not open for further replies.
Top