Panel jobs

Status
Not open for further replies.

guschash

Senior Member
Location
Ohio
How many guys use a 2' or bigger/smaller nipple to being NB into a panel when doing a service change. Or do use romax connectors for each NB entering the panel. What is the article that talks about how many wires can enter through a short nipple before you have to derate.
 

kwired

Electron manager
Location
NE Nebraska
How many guys use a 2' or bigger/smaller nipple to being NB into a panel when doing a service change. Or do use romax connectors for each NB entering the panel. What is the article that talks about how many wires can enter through a short nipple before you have to derate.

The requirements for using the nipple as mentioned are in 312.5(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:
(a) Each cable is fastened within 300 mm (12 in.), measured along the sheath, of the outer end of the raceway.
(b) The raceway extends directly above the enclosure and does not penetrate a structural ceiling.
(c) A fitting is provided on each end of the raceway to protect the cable(s) from abrasion and the fittings remain accessible after installation.
(d) The raceway is sealed or plugged at the outer end using approved means so as to prevent access to the enclosure through the raceway.
(e) The cable sheath is continuous through the raceway and extends into the enclosure beyond the fitting not less than 6 mm (? in.).
(f) The raceway is fastened at its outer end and at other points in accordance with the applicable article.
(g) Where installed as conduit or tubing, the allowable cable fill does not exceed that permitted for complete conduit or tubing systems by Table 1 of Chapter 9 of this Code and all applicable notes thereto.

You can't just stuff them into any nipple you have a minimum of 18" and a maximum of 10'. If longer than 24" you will have to derate conductors for "bundling". Cables must also be fastened within 12 inches of entering the nipple and the nipple must be plugged or sealed somehow. Those are the most common misapplications I usually see with this allowance.
 

guschash

Senior Member
Location
Ohio
Thanks kwired I just found it in the 2011. It says "enter the top", is it the same for entering from side. Hope this isn't a dumb question.
 

guschash

Senior Member
Location
Ohio
Sorry I just re-read it and answer my question. I thought it wasn't a good idea to use short nipples but as long as follow 312 (C )(g) you should be ok.
 

kwired

Electron manager
Location
NE Nebraska
Thanks kwired I just found it in the 2011. It says "enter the top", is it the same for entering from side. Hope this isn't a dumb question.

My quote was from 2008 NEC. Reading condition b, "(b) The raceway extends directly above the enclosure", I would assume that it means enter the top although it does not say that
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Sorry I just re-read it and answer my question. I thought it wasn't a good idea to use short nipples but as long as follow 312 (C )(g) you should be ok.
If you are using (g), then you must also comply with (a) through (f). They are all part of the exception to the general rule in 312.5(C) that says each cable must be secured to the enclosure.
 

guschash

Senior Member
Location
Ohio
Don, I don't see how you could use ( g ) and still secure each cable. But I agree with you that it say "all conditions are met".
 

220/221

Senior Member
Location
AZ
How many guys use a 2' or bigger/smaller nipple to being NB into a panel when doing a service change. Or do use romax connectors for each NB entering the panel. What is the article that talks about how many wires can enter through a short nipple before you have to derate.


Certain geographical locations allow this type of installation. In AZ, all the cables enter the exterior panels thru a single opening thru a bushing of some sort, usually a chase nipple or plastic snap in bushing.
 

iwire

Moderator
Staff member
Location
Massachusetts
Certain geographical locations allow this type of installation. In AZ, all the cables enter the exterior panels thru a single opening thru a bushing of some sort, usually a chase nipple or plastic snap in bushing.

If I recall they require a 3" long raceway.:p
 

kwired

Electron manager
Location
NE Nebraska
(g) Where installed as conduit or tubing, the allowable cable fill does not exceed that permitted for complete conduit or tubing systems by Table 1 of Chapter 9 of this Code and all applicable notes thereto.

If using (g) you have a conduit or tubing system and to have that you will have on both ends of the conduit or tubing an enclosure or conduit body or transition fitting of some type to another raceway or wiring method. You will have to derate conductors if the conduit or tubing is more than 24 inches long. You will be able to use 60% fill however on less than 24 inch nipples.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Don, I don't see how you could use ( g ) and still secure each cable. But I agree with you that it say "all conditions are met".
The main rule says you have to secure each cable, the Exception lets you skip securing each cable, but only when you comply with all the parts of the exception.
 
Status
Not open for further replies.
Top