Different phase, same conduit

[inspector 102]

Have a 3 phase meter that serve a 200 amp 3 phase disco and a 200 amp single phase disco that has all 5 conductors running through a 2 1/2 RMC into a gutter then into each disco. Is there an issue with single phase and 3 phase in the same conduit. Conduit fill does not appear to be issue ( .3117 x 5 = 1.5585, 1.946 allowable @ 40%). Is there a concern of heat build-up or parallel conductors? Thank for advice.

 

[bdarnell]

I thought disco was out.

Seriously though, aren't you short a few conductors ? You said 5 and the three phase service would require at least 3 even if was 3 phase 3 wire, and the single phase would need 3 also, assuming it's 120/240.

How did they accomplish this in terms of metering ? Are both services connected to the same meter ??

 

[inspector 102]

The metering is done through a single meter with double barrel lugs for terminations. The 5 conductors I refered to are the "current carrying" conductors and there are grounded conductors in the conduit also. This situation was described to me by another inspector and does not sound quite proper, but can't find a reason it would not be allowable. Looking for clues.

 

[bdarnell]

As long as they are all service conductors, I don't think there is a violation here.

230.7 is one section that applies.
300.3(C) also.

 

[pierre]

If they are supplied by the same Service Drop, then they are the same service, even if they are different service entrance conductors. I do not see an issue with this either.
If reliability is an issue, it is probably a design issue here.

 

[Gmack]

Parallel

Parallel

If this arrangement as described lost its neutral, say, from the utility or somewhere on the meter line side, then we might have parallel ground paths to the electrode similar to or as applied in separately derived systems.

It may be "objectionable" ground path. It would help to know more on the grounding electrode conductor arrangement.