Reviewing Article 250 - 250.24(C)(2)

[Jerramundi]

Hey guys. Just doing some review of article 250 and I have a question about 250.24(C)(2) Parallel Conductors in Two or More Raceways.

250.24(C)(2) Parallel Conductors in Two or More Raceways [states] If the ungrounded service entrance conductors are installed in parallel in two or more raceways, the grounded conductor shall also be installed in parallel. The size of the grounded conductor in each raceway shall be based on the total circular mil area of the parallel ungrounded conductors in the raceway, as indicated in 250.24(C)(1), but not smaller than 1/0 AWG.

Does this mean that if we a triple meter bank, fed by a single set of overhead service conductors, that has 3 sets of service entrance conductors, in 3 different raceways, feeding 3 100A individual services, that each grounded conductor cannot be smaller than 1/0?

Does this also mean that the ungrounded conductors also cannot smaller than 1/0 since conductors in parallel must be similar??

Does this also also mean that the MBJ's in the individual service equipment enclosures should be sized to 1/0 ungrounded conductors???

Am I reading this correctly or just into it too much....

 

[LarryFine]

Does this mean that if we a triple meter bank, fed by a single set of overhead service conductors, that has 3 sets of service entrance conductors, in 3 different raceways, feeding 3 100A individual services, that each grounded conductor cannot be smaller than 1/0?

Does this also mean that the ungrounded conductors also cannot smaller than 1/0 since conductors in parallel must be similar??

Does this also also mean that the MBJ's in the individual service equipment enclosures should be sized to 1/0 ungrounded conductors???

No to all, because the load ends of those drops would not be connected together, so they're not paralleled.

No, because the load ends of those drops would not be connected together, so they're not paralleled.
Am I reading this correctly or just into it too much....

Way too much.

 

[Jerramundi]

No to all, because the load ends of those drops would not be connected together, so they're not paralleled.

I understand that this particular code reference is premised on a reference to the ungrounded conductors installed in parallel... but they are connected at the transformer, so if there's ANY 240V circuit in the system, would that not then make these ungrounded conductors function as paralleled conductors?

The end implication being that, in services w/ multiple sets of ungrounded service entrance conductors in different raceways, the conductors should never be smaller than 1/0 AWG??

 

[infinity]

If they're not connected together at both ends they're not parallel conductors.

 

[Eddie702]

Maybe I am thinking of this wrong but the paralleled conductors end at the supply side of the meter socket. The load side is not n parallel

 

[Jerramundi]

I suppose I'm overthinking this. I just thought I recalled hearing electrician talk around the beer cooler that 100A services shouldn't go below 1/0... and when I read this section, I thought this might be where it came from. Just wanted to make sure I didn't have to size me MBJ to 1/0 for this 100A service.