Existing set up from the early 90's had the meter on the residence, fed underground from overhead service drop approx 150' with the last 10' or so under concrete most likely URD. POCO needed to reroute the service drop, they moved the meter from the house to the overhead service drop pole, meter has a self contained 200 amp breaker, so thus it is the service disconnecting means. Existing 3 wire setup was left in place (allowed in earlier versions of the NEC) now at automatic transfer switch and generator are in the works. Appropriate to leave the 3 wire feed without a e.g.c to the residence. Based on the 2005 NEC
Transfer Switch and Existing 3 Wire Feed
- Thread starter eds
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LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
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- Electrical Contractor
If I'm not mistaken, a switch would allow the 3 wires to be considered service conductors, but an OCPD makes them a feeder.
- Location
- Tennessee NEC:2017
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- Semi-Retired Electrician
Op said he had a meter/main with a 200A breaker.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
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- Electrical Contractor
I know. I was suggesting that the 3-wire supply needs to be 4-wire.
That would mean the ATS need not be service-rated, I believe.
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- Tennessee NEC:2017
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- Semi-Retired Electrician
wwhitney
Senior Member
- Location
- Berkeley, CA
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- Retired
I would think that in the context of 250.32(B)(1) Exception 1, a service entrance rated transfer switch would be the proper type to use.
Cheers, Wayne
Cheers, Wayne
Even if it has a meter main in front of it. Meter main has a 200 amp ocpd
wwhitney
Senior Member
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- Berkeley, CA
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- Retired
- Location
- Placerville, CA, USA
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I think the detailed resolution depends on whether POCO considers that by making that change they moved the service point from its original location to a new one. The 200 breaker at the pole is not reasonably located to be the main disconnect of the building, but it may still qualify as the service disconnect.
The question of whether the existing 3 wire service conductors, now feeder conductors, can continue to be grandfathered in even when the ATS and generator are added is yet a third question.
The question of whether the existing 3 wire service conductors, now feeder conductors, can continue to be grandfathered in even when the ATS and generator are added is yet a third question.
wwhitney
Senior Member
- Location
- Berkeley, CA
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- Retired
I don't see why the applicability of 250.32(B)(1) Exception 1 would be affected by adding an ATS and a generator.
Cheers, Wayne
Cheers, Wayne
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