Thread: How many wires through opening of service panel

Can somebody please direct me to the code section that pertains to this problem?

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Originally Posted by Dylan Whitehead

Can somebody please direct me to the code section that pertains to this problem?

What problem? Are you talking about the bundling of the wires? I don't see that as a problem because of the short distance it covers.

That is just plain old *not allowed*.

From the 2008 NEC. (underlining is mine)
- ARTICLE 408 Switchboards and Panelboards
- - III. Panelboards
- - - 408.38 Enclosure.
- - - - Panelboards shall be mounted in cabinets, cutout boxes, or enclosures designed for the purpose and shall be dead-front.
Exception: Panelboards other than of the dead-front, externally operable type shall be permitted where accessible only to qualified persons.

- 312.5 Cabinets, Cutout Boxes, and Meter Socket Enclosures.
- - Conductors entering enclosures within the scope of this article shall be protected from abrasion and shall comply with 312.5(A) through (C).
- - - (C) Cables. Where cable is used, each cable shall be secured to the cabinet, cutout box, or meter socket enclosure.
- - - - Exception: Cables with entirely nonmetallic sheaths shall be permitted to enter the top of a surface-mounted enclosure through one or more nonflexible raceways not less than 450 mm (18 in.) and not more than 3.0 m (10 ft) in length, provided all of the following conditions are met:
- - - - - (there are 7 conditions which are described, however, the exception itself is not applicable, thus there is no need to post the conditions the exception must meet)

Additionally, there is the problem with bundling and lack of maintaining spacing for which derating is required:
- 310.15 Ampacities for Conductors Rated 0–2000 Volts.
- - (B) Tables.
- - - (2) Adjustment Factors.
- - - - (a) More Than Three Current-Carrying Conductors in a Raceway or Cable. Where the number of current-carrying conductors in a raceway or cable exceeds three, or where single conductors or multiconductor cables are installed without maintaining spacing for a continuous length longer than 600 mm (24 in.) and are not installed in raceways, the allowable ampacity of each conductor shall be reduced as shown in Table 310.15(B)(2)(a). Each current-carrying conductor of a paralleled set of conductors shall be counted as a current-carrying conductor.
- - - - - - (there are 5 exceptions below, none of which apply, thus no need to include them here)

Also, if that is not going to be the "service equipment" with the main service disconnect, then that metal bar connecting the neutral terminal bar and the ground terminal bar together needs to be removed. In removing the cross over bar, which side has the neutral conductors connected to it? in your photo it would need to be the left side. The label may show this as an option, or it may show the neutral on the right side only with the left side for equipment grounding, if so, it is all wrong. Do you have a photo of the entire panel? The panel label?

I ran into that EXACT situation a couple years ago. I can't remember if I posted it on here but I seem to remember all I could find for rules against it was if they ran for a certain length they had to be de-rated. It was new construction and I called the city electrical inspector. He agreed that it wouldn't be his first choice of how to do it but that it wasn't wrong.

I was surprised to say the least.

Originally Posted by Matt Fellman

I ran into that EXACT situation a couple years ago. I can't remember if I posted it on here but I seem to remember all I could find for rules against it was if they ran for a certain length they had to be de-rated. It was new construction and I called the city electrical inspector. He agreed that it wouldn't be his first choice of how to do it but that it wasn't wrong.

I was surprised to say the least.

The length for requiring derating is greater than 24", which looks to be present in the photo.

The condition with all those NM cables through that one fitting is simply not allowed, in addition to the code sections I gave, it also goes back to the catch-all 110.3(B) Listing and Labeling and having to be installed in accordance to its listing and labeling.

Scott: So the amount of wires going through that opening is acceptable?

What makes this acceptable? (Just asking for my own knowledge)

What code section refers this as acceptable?

Originally Posted by Dylan Whitehead

Scott: So the amount of wires going through that opening is acceptable?

What makes this acceptable? (Just asking for my own knowledge)

What code section refers this as acceptable?

Jerry, posted the code. That space does not look like it is more than 24". I would say that it is around 8" to 10" max. Now as for what is above the panel I don't know, but the wires entering through the grommet look OK to me.

Excuse this question but what "space" are you referring to?

Originally Posted by Dylan Whitehead

Excuse this question but what "space" are you referring to?

The "hole" that the NM lines are going into and then into the panel..

The "space" 'starts at' the "hole" in the top of the panel with what looks like 15 NM 2 conductor cables for 30 conductors, then (just outside the "hole") the number of NM cables splits, with 9 2 conductor cables (18 conductors) going to the left and 6 NM 2 conductor cables (12 conductors) going to the right, then up to the top plate, through the top plate in a similar manner, then out to the ceiling area (where they *may* spread out, but I doubt it), leaving a total measurement from the "hole" at the top of the panel to where the conductors come out through the top plate of greater than 24".

Also recall the recent other thread where Jeff pointed out the new clarification code requirement specifically addressing multiple NM cables through wood top plates. That is precisely what one would expect to find here - two holes through the top plate, one with 9 NM cables and one with 6 NM cables, or may a couple of more holes, but with many NM cables through each hole.

Add to that the fact that the only "securing" going on at the entrance to the cabinet enclosure it "friction" from jamming as many NM cables as possible into that one chase nipple.

Jerry, thanks for clearing that up for me, the whole "space" thing. The space is a minimum of 24", just not shown in the pic. The cables do go through the top plate into the attic area where they do spread out. They are also secured to the studs on both sides above the panel entrance.

Since the space is 24" or more, it is correct to call this out?

Originally Posted by Dylan Whitehead

Since the space is 24" or more, it is correct to call this out?

Instead of using the term "space" I would use the term "length".

Yes, if the length of the bundling/lack of maintaining spacing exceeds 24 inches I always called it out.

Here is an example of what that derating does, whether or not the AHJ enforces and applies that derating, it is "required" for the safety and protection of those conductors under the conditions they are used:

Those are #12 AWG NM cables.

On the left side with 18 conductors, the derating factor is 0.50.

On the right side with 12 conductors, the derating factor is 0.50.

They both fall within the 10-20 conductor row, which is 0.50.

Do they go into the attic? do they go into unconditioned space under a second floor which is not insulated from outside?

Presuming worst case and the conductors go into the attic, then they must first be derated for ambient temperature, just like all conductors must be, bundled/lack of maintaining spacing or not - *ALL* conductors are derated for ambient.

You are in Texas, where it gets pretty warm in the attics, so the ambient temperature which needs to be applied would most likely be the 132-140 degree F with a derating factor of 0.71. Note that if your attics get over 140 degrees, and some in Texas get to over that, the next ambient range is 141-158 degrees with a derating factor of 0.58.

That ambient derating is applied to the conductor ampacity rating for its 90 degree C insulation, which is 30 amps for #12 AWG with that insulation.

=< 140 degree attic: 30 amps x 0.71 = 21.3 amps with NO derating for bundling

21.3 amps x 0.50 = 10.65 amps derated for 10-20 conductors for that #12 NM cable

>140 degree attic: 30 amps x 0.58 = 17.4 amps with NO derating for bundling.

17.4 amps x 0.50 = 8.7 amps derated for 10-20 conductors for that #12 NM cable

Yep, I'd sure mention it.

Who ever did that panel has no excuse for doing it in such a manner given that there are ample knock-outs. Someone was trying to save some money. Cheap, cheap, cheap. However on the bright side it would not cost much to remedy.

Let's not confuse 'panels' with 'panelboards,' please. After all, EVERY panel maker offers panels and covers specifically made for mounting on the surface of walls.

Nor is there any requirement that the cables going to the panel be enclosed within walls.

What is required, however, is that the cable connect to the box using the proper fittings. While there are several fittings available that are listed for two flat cables, I'm not aware of any for more than that. In any event, that bushing doens't connect the cables to the box at all.

Since theere is no connector, there is no protection of the electrical cinnections from any tugs and pulls the cables may receive. Providing such 'strain relief' is the reason for the connector requirement.

Originally Posted by John Steinke

Let's not confuse 'panels' with 'panelboards,' please.

"panelboards" are the interiors, which must be placed in a proper "cabinet" enclosure, of which most, if not all, manufacturers provide matching "cabinets" and "panelboards" which are listed and labeled for each other.

Nor is there any requirement that the cables going to the panel be enclosed within walls.

No one said cables were required to be enclosed in a wall????