Transitioning Wire from Interior 2x4 wall Through Back of Exterior Surface Mounted Panel

ESolar

Senior Member
This topic has been hashed out many times. Even so, I still feel that I don't understand how to make a code compliant transition from an interior wall through the back of an exterior surface mounted breaker box. My issue is with the entrance through the back - I want a code compliant transition through the back, without vertical sleave from the top of the panel to the attic.

Apparently, the local AHJs allow the wires, even NM, to run through one big chase nipple through the back (provided they are attached to a stud within 12" of the chase nipple). This job has UF and SER so the wires are rated for wet locations - no NM. But my understanding is that a bunch of wires through a chase nipple is not compliant.

Wires: #6 AL SER, 2 x #8 CU SER, 1 x #12 UF, and 2 x #14 UF.
Panel 125A 8/16 surface mount

So how does one perform code compliant wire transition from the interior of a 2x4 wall (stucco exterior) through the back of the exterior surface mounted panel? Does it require an individual chase nipple for each wire? If so, sounds messy, hence the vertical sleave.

If not possible, what are the other alternatives? Conduit from the bottom or lower sides? What is the preferred method?
 

Seven-Delta-FortyOne

Goin’ Down In Flames........
Location
Northern California
Occupation
EC and GC
This has never ever been an issue for me.

And with a strict reading of the code, as long as the nipple does not exceeded 24”, no derating is required.

And while raceways outdoors are considered a wet location, romex has been fed into exterior mounted panels for as long as romex has existed.

The Code is great, but it’s not the Holy Bible.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Apparently, the local AHJs allow the wires, even NM, to run through one big chase nipple through the back (provided they are attached to a stud within 12" of the chase nipple). This job has UF and SER so the wires are rated for wet locations - no NM. But my understanding is that a bunch of wires through a chase nipple is not compliant.
According to the NEC the chase nipple method is not compliant. Each cable needs to terminate in a connector listed for the number of conductors in it. Some allow two or three cables but the listing is the limiting factor.
 

tom baker

First Chief Moderator
Staff member
I used a 4x4x18 wireway behind the panel recessed in the wall. 2 1 1/2 nipples into panel at bottom. On inside wall run romex into WW via clamps. Strip jacket, terminate egc into a ground bar, run wires into panel. Group hot and neutral wires with zip ties in panel.
 

wwhitney

Senior Member
Location
Berkeley, CA
Occupation
Retired
According to the NEC the chase nipple method is not compliant. Each cable needs to terminate in a connector listed for the number of conductors in it. Some allow two or three cables but the listing is the limiting factor.
I thought the only issue was 312.5(C), which says that "each cable shall be secured to the cabinet." Seems like there are other ways of securing a cable than using a connector. E.g., how about some listed cable ties screwed to the back of the cabinet, one per cable coming through a nipple?

Cheers, Wayne
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
I thought the only issue was 312.5(C), which says that "each cable shall be secured to the cabinet." Seems like there are other ways of securing a cable than using a connector. E.g., how about some listed cable ties screwed to the back of the cabinet, one per cable coming through a nipple?

Cheers, Wayne
No inspector I know is going to say that complies with 312.5(C).
 
Do you have access to inside the wall to strap the cables? If so I really don’t see an issue if you’re saying AHJ allows what you’re doing. I had a thread a few weeks back about this and the consensus was that it’s totally fine to run these cables through a conduit sleeve and into the panel. But if you can get in the wall then why not just make a sleeve a few inches long to protect the wires as they pass through the wall and then have them strapped immediately before entering the sleeve? That Arlington connector is sweet and I’ve passed many inspections by running lots of cables through one 2” nm clamp connector even though I probably shouldn’t have. Apologies if I’m oversimplifying or misunderstanding something.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
I would refer them to Charlie's Rule. If it's secured to the cabinet, that suffices for 312.5(C) compliance.

Cheers, Wayne
You just playing word games with a zero real world application. For 100 years we've been attaching cables to the panel via a listed connector unless it meets the exception in 312.5(C). Using a cable tie screwed to the cabinet and a chase nipple is not passing any inspection around here and more than likely not anywhere else for that matter.
 

wwhitney

Senior Member
Location
Berkeley, CA
Occupation
Retired
For 100 years we've been attaching cables to the panel via a listed connector.
Show me the NEC language requiring a listed connector when securing the cable to the cabinet, and I'm with you. Otherwise, you're confusing a standard industry practice with a code requirement.

Cheers, Wayne
 

ESolar

Senior Member
Show me the NEC language requiring a listed connector when securing the cable to the cabinet, and I'm with you. Otherwise, you're confusing a standard industry practice with a code requirement.

Cheers, Wayne
I agree with you Wayne (maybe a little confirmation bias on my part). The code says nothing about how to secure the cable other than using a listed product. The fact that the knockout clamps are the norm appears to be standard practice. But in fact, the requirement for the knockouts is to ensure that the cable can't be damaged, not that it be clamped at the knockouts. That's just a very convenient and clean way to do it. I agree with Infinity that many AHJs are not going to recognize an alternate method to secure the cable as code compliant. But that's because it is rarely done, and rarely has to be, not because it doesn't meet code.

Here running through a chase nipple without being secured to the cabinet is even accepted. But that always bothered me if someone called me on it after the fact. Securing the cable to the box with an alternate listed method would make it compliant and could also be a retrofit provided enough length of wire cover was maintained within the box.

Can you provide an example of a listed tie down/clamp that could be used within a breaker box?
 

ESolar

Senior Member
See the Arlington NM844 at the bottom of page 2 of the PDF here:

I don't think that that would work because the wire has to pass from dry interior to wet exterior into the back. There is no way to seal that. Hence the chase nipple. See Wayne's comment about secure the cable within the box after it passes through the chase.

It is worth noting that the number of responses and differing opinions is why I posted this.
 

ESolar

Senior Member
I would refer them to Charlie's Rule. If it's secured to the cabinet, that suffices for 312.5(C) compliance.

Cheers, Wayne
Where can I find "Charlie's Rule"
312.5(C) doesn't have any requirement about using a listed product.

Cheers, Wayne
So in conclusion: 312.5(C) relates to attempts to bundle cable into a box without securing it:

"312.5(C) Cables. Where cable is used, each cable shall be secured to the cabinet, cutout box, or meter socket enclosure."

It says nothing about the method of securing the cable. Securing with usual knockout cable clamps, although standard, is not a requirement.

The exception to 312 allows the bundling of, specifically, NM cable without being secured to the box.

"Exception: Cables with entirely nonmetallic sheaths shall be permitted ..."

In the case of an outdoor box, NM is not allowed. Therefore, the exception does not apply.

Bundled SER and UF from indoor to the outdoor box is allowed, as long as the cable can be secured within the box. In the specific case, the cable transitions from UF to NM in the first receptacle. So the run to the box is UF. The feeder is SER.
 

wwhitney

Senior Member
Location
Berkeley, CA
Occupation
Retired
The exception to 312 allows the bundling of, specifically, NM cable without being secured to the box.

"Exception: Cables with entirely nonmetallic sheaths shall be permitted ..."
That would cover UF and SER as well. But the details of the exception make it difficult or impossible to use outdoors.

Cheers, Wayne
 

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
For a Wood framed wall I use a piece of FMC or EMT out the back of the exterior panel into a to the first box like a 4-11/16 with a plaster ring if its going to be finished.
 
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