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-   -   Maximum wires in a 2 1/2" nipple (http://www.diychatroom.com/f18/maximum-wires-2-1-2-nipple-146728/)

elmaur 06-11-2012 01:29 PM

Maximum wires in a 2 1/2" nipple
 
My main service panel is mounted on an exterior wall. I have a 2 1/2" x 10" nipple connected to the back of the panel going through to the interior of a sheetrock wall. I am doing some rewire and adding new circuits. Is there a maximum number of wires allowed in the nipple?

Jim Port 06-11-2012 01:56 PM

What is on the other side of the nipple?

elmaur 06-11-2012 02:07 PM

Quote:

Originally Posted by Jim Port (Post 941010)
What is on the other side of the nipple?

The nipple extends through the exterior brick wall into a sheetrock wall. The wall is open from the inside and wires are being pulled from various points in the house through a ceiling chase.

Code05 06-11-2012 02:30 PM

I am seeing 60% fill and no derating here. No?

Chapter 9, T1, Note(4) Where conduit or tubing nipples having a maximum
length not to exceed 600 mm (24 in.) are installed between
boxes, cabinets, and similar enclosures, the
nipples shall be permitted to be filled to 60 percent of
their total cross-sectional area, and 310.15(B)(3)(a) adjustment
factors need not apply to this condition.

Jim Port 06-11-2012 02:44 PM

I was concerned about branch circuits being mixed with unfused service conductors.

I agree on the 60%, no derate.

Code05 06-11-2012 02:48 PM

Quote:

Originally Posted by Jim Port (Post 941042)
I was concerned about branch circuits being mixed with unfused service conductors.

I agree on the 60%, no derate.

If service conductors are involved, I agree, we have a no go.

elmaur 06-11-2012 02:53 PM

Quote:

Originally Posted by Jim Port (Post 941042)
I was concerned about branch circuits being mixed with unfused service conductors.

I agree on the 60%, no derate.

How do I know when I am at 60%? I could just measure but is there some thing else to consider?What is the reason for this limitation?

elmaur 06-11-2012 02:56 PM

Quote:

Originally Posted by Code05 (Post 941044)
If service conductors are involved, I agree, we have a no go.

What are service conductors? Conductor supplying main service such as from the power company?

Code05 06-11-2012 03:19 PM

Quote:

Originally Posted by elmaur (Post 941049)
What are service conductors? Conductor supplying main service such as from the power company?

Yes. They are unfused, except at the pole/tranformer.

Code05 06-11-2012 03:22 PM

Quote:

Originally Posted by elmaur (Post 941048)
How do I know when I am at 60%? I could just measure but is there some thing else to consider?What is the reason for this limitation?

Heat and insulation breakdown. Do you need us to explain pipe fill and how to calculate it, it is not hard.

Jim Port 06-11-2012 03:23 PM

To figure the 60% you would need to compute the area of the conductors to be installed vs 60% of the cross sectional area of the 2" nipple.

These values are computed for you in the Chapter 9 Tables of the NEC.

elmaur 06-11-2012 04:30 PM

Quote:

Originally Posted by Code05 (Post 941068)
Heat and insulation breakdown. Do you need us to explain pipe fill and how to calculate it, it is not hard.

I may not need to calculate. I think I'll use another knockout on the back of the panel and divide the wire pulls between the 2 entry points and probably should be good.

stickboy1375 06-11-2012 05:24 PM

Quote:

Originally Posted by elmaur (Post 941119)
I may not need to calculate. I think I'll use another knockout on the back of the panel and divide the wire pulls between the 2 entry points and probably should be good.

You could easily install 264 #12 THHN, THWN conductors in a 2 1/2" nipple, I doubt you'll go over... lol... This was using EMT as your nipple, but regardless... I seriously doubt you will have any issues.

stickboy1375 06-11-2012 05:29 PM

Quote:

Originally Posted by elmaur (Post 940993)
My main service panel is mounted on an exterior wall. I have a 2 1/2" x 10" nipple connected to the back of the panel going through to the interior of a sheetrock wall. I am doing some rewire and adding new circuits. Is there a maximum number of wires allowed in the nipple?

By the way, is there a junction box or were you sleeving cables through this nipple?

elmaur 06-11-2012 08:18 PM

Quote:

Originally Posted by stickboy1375 (Post 941176)
By the way, is there a junction box or were you sleeving cables through this nipple?

No junction box. My wire pulls are coming from various areas in the house and through the nipple into the main service panel.


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