Too Many Conductors in a Raceway

Ravenvalor

Senior Member
Hello,

I looked at a dimmer pack in a large (1,000-seat) church that had a 1.25" PVC raceway with a whopping 32 - current carrying conductors in it (16-ungrounded and 16-grounded. About 8 of them were terminated on 20-amp rated circuit breakers and the other 8 were not terminated at all but were intended to be terminated onto 20-amp circuit breakers at a later date. To me the code violations are two-fold. The first is the PVC in a place of assembly and the second is the overfill of the raceway. This installation was made in the early nineties. I was wondering if the installation met the NEC requirements of the early nineties? I would like to utilize those other unused conductors onto 20-amp circuit breakers.

Thank You,
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
I don't know when conductor fill came into being but my suspicion is that this was not compliant. Even if it was compliant, imo if you use the remaining conductors as current carrying conductor then you would not be compliant.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
32- 12 AWGs in 1.25 should be fine.

The in use CCC count is a bit high for 20 amp circuits.
I agree if we assume that they're #12 THHN. That would put the derate value at a maximum of 15 amps on each conductor.
{30amps * 50% = 15amps}
 

Smart $

Esteemed Member
Location
Ohio
I agree if we assume that they're #12 THHN. That would put the derate value at a maximum of 15 amps on each conductor.
{30amps * 50% = 15amps}
That depends. He mentioned 8 on 20A, 8 not connected, but nothing about the other 16... and I assume those are or were to be grounded conductors. If 1?, the CCC count could be as low as 8. If 3? wye, count could be as low as 9.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
32- 12 AWGs in 1.25 should be fine.

The in use CCC count is a bit high for 20 amp circuits.
I agree if we assume that they're #12 THHN. That would put the derate value at a maximum of 15 amps on each conductor.
{30amps * 50% = 15amps}
That depends. He mentioned 8 on 20A, 8 not connected, but nothing about the other 16... and I assume those are or were to be grounded conductors. If 1?, the CCC count could be as low as 8. If 3? wye, count could be as low as 9.
Not quite the way I read it. He has 8 circuits with 8 separate neutrals that's 16 CCC's disregarding the spare conductors. From the OP:

I looked at a dimmer pack in a large (1,000-seat) church that had a 1.25" PVC raceway with a whopping 32 - current carrying conductors in it (16-ungrounded and 16-grounded. About 8 of them were terminated on 20-amp rated circuit breakers and the other 8 were not terminated at all but were intended to be terminated onto 20-amp circuit breakers at a later date.
 

Smart $

Esteemed Member
Location
Ohio
Not quite the way I read it. He has 8 circuits with 8 separate neutrals that's 16 CCC's disregarding the spare conductors. From the OP:
Perhaps... but that is an assumption. Let's say for the sake of discussion that all 16 grounded are connected, how many are CCC's?
 

Ravenvalor

Senior Member
Just Called Tech Support. New Packs have 10-Amp Rated Circuit Breakers in them.

Just Called Tech Support. New Packs have 10-Amp Rated Circuit Breakers in them.

Good News. The manufacturer "ETC" has just returned my call and has clarified that the new dimmer packs that I will be replacing the old ones with have 10-amp circuit breakers in them. According to Table 310.15(B)(3)(a) the conductors can be de-rated to 12-amps each. Now all that I have to do is get the local electrical inspector to approve of the existing PVC.

Thanks for all of the helpful advice.
 

Smart $

Esteemed Member
Location
Ohio
Good News. The manufacturer "ETC" has just returned my call and has clarified that the new dimmer packs that I will be replacing the old ones with have 10-amp circuit breakers in them. According to Table 310.15(B)(3)(a) the conductors can be de-rated to 12-amps each. Now all that I have to do is get the local electrical inspector to approve of the existing PVC.

Thanks for all of the helpful advice.
You'd still have to change the breakers to 15A. The 10A CB's in the dimmer packs are supplementary OCPD and are not a substitute for branch circuit OCPD [240.10].

If the dimmer packs are cord-and-plug connected, another issue could arise if the circuits power more than one receptacle each (a duplex receptacle by definition is a multiple receptacle) [100.I, 210.19(A)(2)]... but you could remove the tabs to disconnect one side of the duplex.
 

GoldDigger

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Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
That depends. He mentioned 8 on 20A, 8 not connected, but nothing about the other 16... and I assume those are or were to be grounded conductors. If 1?, the CCC count could be as low as 8. If 3? wye, count could be as low as 9.
Good point, especially if he rearranges the existing circuits.
Not counting the grounded conductors would require that the circuits actually be wired as MWBCs. In the OP's case they are not currently so wired, but unless he is forced to always count the neutral because of non-linear load from the dimmer packs he can rewire his 8 existing circuits as MWBCs and save 8 CCCs, getting a total of 8 CCC plus 4 unused former grounded conductors (which are the wrong color to use for most other purposes) and 16 spares.
 

Ravenvalor

Senior Member
You'd still have to change the breakers to 15A. The 10A CB's in the dimmer packs are supplementary OCPD and are not a substitute for branch circuit OCPD
The breaker feeding the dimmer pack will be a 40-amp 208-volt 2-pole breaker. The 10-amp breakers are integral to the dimmer packs and cannot be replaced.

Thanks for the heads up on this.
 

GoldDigger

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Location
Placerville, CA, USA
Occupation
Retired PV System Designer
The breaker feeding the dimmer pack will be a 40-amp 208-volt 2-pole breaker. The 10-amp breakers are integral to the dimmer packs and cannot be replaced.

Thanks for the heads up on this.
So the multiple circuits are the output circuits of the dimmer pack! In that case what does the code say is the effective protection of the output circuits? Does the 10A breaker count for that or does each output circuit require 40A wiring?!? Or do you have to install separate UL approved (non-supplemental) breakers for each output?
 
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Smart $

Esteemed Member
Location
Ohio
The breaker feeding the dimmer pack will be a 40-amp 208-volt 2-pole breaker. The 10-amp breakers are integral to the dimmer packs and cannot be replaced.

Thanks for the heads up on this.
Okay... I misinterpreted the conductors as supplying the dimmer packs rather than the other way around.
 
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