Thousands of nm cables through one KO ?

Status
Not open for further replies.

ritelec

Senior Member
Location
Jersey
Hello……..

I don't "think" it's code compliant, but not really sure so thought I'd ask.

I've seen pictures of many (ok not thousands) nm cables sleeved into a 2" or so ko going into panels,
I've also seen pictures of many nm cables sleeved through 1 or 2 foot 2"or so nipples going into panels.

With an appropriately spaced cable support, would this type of install be code compliant?

Thank you.
 

ron

Senior Member
I've always struggled with this too.

Even if a 1000 go through the hole and then "separate" apart, how far apart do they need for it not to be considered bundling requiring derating.
 

peter d

Senior Member
Location
New England
I've always considering that method to be hack and substandard. I realize it's a common method in some parts of the country and that it saves time, but around here we always run 1 or 2 cables per knockout.
 

user 100

Senior Member
Location
texas
I've always considering that method to be hack and substandard. I realize it's a common method in some parts of the country and that it saves time, but around here we always run 1 or 2 cables per knockout.

Ditto. And that "job" in the pic just looks plain awful, violations aside.
 
The code requires the NMs to be secured to the panel see article 312

312.5 (C) has an exception.
You are OK if you sleeve the NM cables like that, as long as the nipple is at least 18", and the panelboard is surface mounted:

312.5 [...]

(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 raceways no less than 450 111m (18 in.) and not more than 3.0 m (10 ft) in length, provided all of the following conditions are met.'
 

iwire

Moderator
Staff member
Location
Massachusetts
312.5 (C) has an exception.
You are OK if you sleeve the NM cables like that, as long as the nipple is at least 18", and the panelboard is surface mounted:

312.5 [...]

(C) Cables. Where cable is used, each cable shall be secured to the cabinet, cutout box, or meter socket enclosure.
Exception.' Cables with entire!.v nonmetallic sheaths shall be permitted to enter the top of a surface-mounted enclosure through one or more raceways no less than 450 111m (18 in.) and not more than 3.0 m (10 ft) in length, provided all of the following conditions are met.'

I am well aware of that exception, but it does not fit the installation in the picture.
 

user 100

Senior Member
Location
texas
312.5 (C) has an exception.
You are OK if you sleeve the NM cables like that, as long as the nipple is at least 18", and the panelboard is surface mounted:

312.5 [...]

(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 raceways no less than 450 111m (18 in.) and not more than 3.0 m (10 ft) in length, provided all of the following conditions are met.'

Key word is 18"-that example shown doesn't qualify.
 

guschash

Senior Member
Location
Ohio
There must be a lot of confusion about this because at my IAEI meeting yesterday, I was ask about this same thing. I personally don't like sieving all my conductors. I would think there would be heat build up but I'm no expert.
 

kwired

Electron manager
Location
NE Nebraska
Ditto. And that "job" in the pic just looks plain awful, violations aside.
Besides the cable entry method, what is visible in that image that is clearly debatable?

There must be a lot of confusion about this because at my IAEI meeting yesterday, I was ask about this same thing. I personally don't like sieving all my conductors. I would think there would be heat build up but I'm no expert.
Derating would be required if sleeve is longer then 24".
 

kwired

Electron manager
Location
NE Nebraska
Or less than 10' or 10% of the circuit length I believe.

I think you are caught on ambient temp corrections where that rule fits in.

With NM cable we need to adjust even where we just have multiple cables through a framing member that has the hole sealed for thermal insulating puropses - but the thing that don't really make sense here is we can fill that 2 inch sleeve with as many cables as we can and still are required to seal the entry so foreign material can't easily enter, but seems to be little information telling us to derate in this circumstance.

I don't pay too close attention or fight one way or another because I don't use that practice and seldom have in the past either, but I see some conflict there in requirements and/or typical enforcement of the requirements.
 

user 100

Senior Member
Location
texas
Besides the cable entry method, what is visible in that image that is clearly debatable?

Besides the 2 violations already mentioned, another one that may come into play here would be 300.4-some of those holes look a little closer than 1 1/4" to that outer edge and also look at the stapled mess just below. If they had just followed the code to start with, it probably would have been an easier job-they did an awful lot of drilling for what they were trying to accomplish.

There may not be any realistic issues, but I kind of look at some of these deals like this too-if they were this sloppy here, where else would they have been sloppy?
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
I think you are caught on ambient temp corrections where that rule fits in.

With NM cable we need to adjust even where we just have multiple cables through a framing member that has the hole sealed for thermal insulating puropses - but the thing that don't really make sense here is we can fill that 2 inch sleeve with as many cables as we can and still are required to seal the entry so foreign material can't easily enter, but seems to be little information telling us to derate in this circumstance.

I don't pay too close attention or fight one way or another because I don't use that practice and seldom have in the past either, but I see some conflict there in requirements and/or typical enforcement of the requirements.

:thumbsup:

unlike ALL the other Code sections which make perfect sense :D
 
Status
Not open for further replies.
Top