Walkercell Infloor System

[wijeguna]

When a "Walkercell" infloor system ( a Wiremold product) is used as a grid to distribute power (in concrete slab), is it needed to consider derating of conductors per NEC Article 310. In this type of grid system, there will be many current carrying conductors in the same raceway which runs from the power panel to the loads.

Is there any exception in NEC for this kind of infloor systems, which doesn't require derating of conductor capacity?

Any ideas !!!

 

[charlie b]

Re: Walkercell Infloor System

310.15(B)(2)(a) calls for derating when more than three current-carrying conductors share a raceway. The Article 100 definition of ?raceway? explicitly includes the type of underfloor system you have described. I conclude that you are stuck with the derating factors.

 

[iwire]

Re: Walkercell Infloor System

Originally posted by wijeguna:
Any ideas !!!

I got a couple.

(1)
Use 10 AWG and you can get 20 current carrying conductors in and still be rated at 20 amps.

If specs allow run multiwire branch circuits, if you do this you could get 19 - 120 volt 20 amp circuits in one raceway.

(2)
If that is not enough you going to need 8 AWG or see if the customer will accept 15 amp breakers.

If you use 10 AWG on 15 amp breakers you can derate .35 (table 310.15(B)(2)(a) ) x 40amps (10 AWG 310.16) = 14 amps

Now use 240.4(B) and you can move up to the next standard size breaker.

With the .35 conductor derating and 15 amp breakers you can put in as many current carrying conductors as you need.

[ July 07, 2003, 09:43 PM: Message edited by: iwire ]

 

[iwire]

Re: Walkercell Infloor System

Bennie all these questions seem like they relate to this thread, why not keep things in context?

Originally posted by Bennie

After applying the derating factors for temperature, and number of conductors in a conduit, do you reduce the load to match the ampacity or reduce the breaker size, or increase the wire size?

If you increased the wire size from No.#14 to No.#12 because of derating, could you put the No.#12 on a 20 amp breaker?

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According to the NEC under what conditions is it a requirement to connect a No.#10cu to a 20 amp breaker?

Derating