Wireway and/or pull and junction box?

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cripple

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Santa Fe, New Mexico
What I have, is a service panel replacement in an existing building, because it is old and outdated. The old panel fed all the circuits in the building, the new design calls out for two new panels one for power and the other for lighting only (voltage both panel is 120Y/208). Not all the conduits are located directly above the panel the design calls out for. The designs call out to install 8?x8?x4? wireway to be able to route the conductors to the designated panel. My question is on wireways. Can one section of 8?x8?x4? wireway be used and classified as a pull box or a junction box in this case, and if so would the 20% fill and the thirty current carry conductor derating rule apply since it is primarily used as a junction box.

[ January 31, 2006, 06:14 PM: Message edited by: cripple ]
 
Re: Wireway and/or pull and junction box?

Yes.
You didn't mention service conductors so I assume they are not involved. If the are watch 230-7.
 
Re: Wireway and/or pull and junction box?

The 30 CCC rule will kill you on an installation like this. You really need to use another method and eliminate the wireway. How about a large pullbox? Or just nipple the two panels together and feed the conductors through the nipple.
 
Re: Wireway and/or pull and junction box?

I don't think that the 20% fill would be any problem. 250 #6 THWN will fit in the 8 x 8 wireway at 20% fill. The 30 conductor derating will be a problem. If you have over 30 conductors at any cross section you will have to derate to 40% or less. How many conductors are involved? What size are they? Can you use multiple wireways to eliminate this problem?
Don
 
Re: Wireway and/or pull and junction box?

I can't say I understand the requirements of auxilary gutters or wireways as far as derating is concerned. If you have over 30 conductors you derate by 45%. There seems to be no consideration of conductor size or the size of the gutter or wireway. ??

edited to add: Additionally, if the gutter or wireway is nonmetallic, derating starts at 4 current carrying conductors.

[ February 01, 2006, 05:37 PM: Message edited by: buck33k ]
 
Re: Wireway and/or pull and junction box?

cripple, anybody "QUALIFIED" to answer this? Oh Yeh! I don't Know everyting but this Group Is definitely "Qualified"
 
Re: Wireway and/or pull and junction box?

buck,
I can't say I understand the requirements of auxilary gutters or wireways as far as derating is concerned. If you have over 30 conductors you derate by 45%. There seems to be no consideration of conductor size or the size of the gutter or wireway.
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The derating rules never look at the conductor size or the size of the raceway or wireway. Ten current carrying #14s in a 4" conduit requires a 50% derating. Note that if the conductors are THWN and the raceway is EMT, 608 conductors are permitted to be installed per the 40% fill rule.
Don

[ February 01, 2006, 06:27 PM: Message edited by: don_resqcapt19 ]
 
Re: Wireway and/or pull and junction box?

I guess my question is,can one section of 8?x8?x4? matallic wireway be used and classified as a pull box or a junction box??????
 
Re: Wireway and/or pull and junction box?

Originally posted by cripple:
I guess my question is,can one section of 8?x8?x4? matallic wireway be used and classified as a pull box or a junction box??????
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The wireway is a wireway and not a junction box. It will be fine if you can avoid using more than 30 current carrying conductors. Beyond that you'll have to derate which IMO makes the wireway useless. The purpose of the wireway in your example is to route the conductors into either of two panels. This would provide you flexibility, however the derating will probably make your installation more difficult than if you used a large junction box instead of the wireway. As I mentioned another option would be to bring the conduits directly in to the panel(s) and nipple the panels together. This would allow you to bring circuits into either of the two panels. not the best installation but it is code compliant.
 
Re: Wireway and/or pull and junction box?

I guess my question is,can one section of 8?x8?x4? metallic wireway be used and classified as a pull box or a junction box??????
Click to expand...
Even if you could reclassify the wireway as a junction box, you would still have to derate unless you maintained separation between the conductors. That would not be easy and not sure how the AHJ would see it.
Don
 
Re: Wireway and/or pull and junction box?

Don,

What article requires derating or separation in a junction box?
 
Re: Wireway and/or pull and junction box?

The wireway is 4' long...the wires will be "bundled" for more than 24". 310/12(B)(2)(a).
Don
 
Re: Wireway and/or pull and junction box?

Originally posted by don_resqcapt19:
The wireway is 4' long...the wires will be "bundled" for more than 24". 310/12(B)(2)(a).
Don
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I think that it's a stretch to say that conductors in a junction box or wireway are bundled unless they are physically tied together. We know that up to 30 CCC's are permitted in a wireway without derating. A wireway is a raceway, a junction box isn't. I've never seen or heard of 310.15(B)(2) being applied to junction boxes.
 
Re: Wireway and/or pull and junction box?

I wonder if it wouldn't be a good idea to drop the requirements for derating in auxilary gutters and wireways and maintain the 20% rule. After all, we don't derate in cabinets and load centers where the conductors are in close proximity for over 24", and there are no ill effects.

The purpose of auxilarly gutters is to supplement wiring space at distribution centers and switchboards. Derating in addition to the 20% rule defeats this purpose.
 
Re: Wireway and/or pull and junction box?

I am thinking if you were to install Barrier strips in the wireway, and staggered the way you entered and exited the wireway in regard to conductors you could be code compliant.

Jim Lockard
 
Re: Wireway and/or pull and junction box?

Originally posted by jimkaki:
I am thinking if you were to install Barrier strips in the wireway, and staggered the way you entered and exited the wireway in regard to conductors you could be code compliant.

Jim Lockard
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Jim, You may be correct, but as I said before this kind of defeats the purpose of using a wireway. It would be easier to simply use a pullbox to avoid any problems with the 30 ccc rule.


I wonder if it wouldn't be a good idea to drop the requirements for derating in auxilary gutters and wireways and maintain the 20% rule. After all, we don't derate in cabinets and load centers where the conductors are in close proximity for over 24", and there are no ill effects.
Click to expand...
I agree with Buck. For the installation described in the OP, IMO the 30 ccc rule shouldn't apply until after some given length. I'd like to see it set at say 5' for installations just like Cripple described in the OP.

[ February 03, 2006, 04:55 AM: Message edited by: infinity ]
 
Re: Wireway and/or pull and junction box?

I think that it's a stretch to say that conductors in a junction box or wireway are bundled unless they are physically tied together. We know that up to 30 CCC's are permitted in a wireway without derating. A wireway is a raceway, a junction box isn't. I've never seen or heard of 310.15(B)(2) being applied to junction boxes.
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If the wires are just laying in a group on the bottom of a wireway or junction box for more than 24" with no method to insure separation, I would require derating. Besides, in this case, even if you call it a junction box, it is being used as a wireway.
Don

[ February 03, 2006, 08:47 AM: Message edited by: don_resqcapt19 ]
 
Re: Wireway and/or pull and junction box?

If the wires are just laying in a group on the bottom of a wireway or junction box for more than 24" with no method to insure separation, I would require derating. Besides, in this case, even if you call it a junction box, it is being used as a wireway.
Don
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I would have to disagree. This is not bundling. Besides you referenced article 310.15(B)(2)(a), the adjustment factors are for a raceway or cable. A junction box is neither.


Article 100:

Raceway. An enclosed channel of metal or nonmetallic materials designed expressly for holding wires, cables, or busbars, with additional functions as permitted in this Code. Raceways include, but are not limited to, rigid metal conduit, rigid nonmetallic conduit, intermediate metal conduit, liquidtight flexible conduit, flexible metallic tubing, flexible metal conduit, electrical nonmetallic tubing, electrical metallic tubing, underfloor raceways, cellular concrete floor raceways, cellular metal floor raceways, surface raceways, wireways, and busways.
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Wireways are on the list but junction boxes are not.
 
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