Two service entrance feeders tapped from same utilty transformer

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mull982

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Are there any special requirements for having two service entrance feeders tapped from the same transformer? If an existing utility transformer has two separate SE feeders feeding two lineups located in the same building are there any special requirements outside of 230.90 for SE feeders? Do the tap rules of 240.21(C) apply here?

From what I can tell there are no special requirements for this case other than the standard requirements of 230.90 which would require these feeders only to have overload protection at the SE equipment they feed and be routed outside except for where they enter the building with no specific limitation on length for the outdoor routing?
 
roger

roger

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mull982 said:
Are there any special requirements for having two service entrance feeders tapped from the same transformer? If an existing utility transformer has two separate SE feeders feeding two lineups located in the same building are there any special requirements outside of 230.90 for SE feeders? Do the tap rules of 240.21(C) apply here?

From what I can tell there are no special requirements for this case other than the standard requirements of 230.90 which would require these feeders only to have overload protection at the SE equipment they feed and be routed outside except for where they enter the building with no specific limitation on length for the outdoor routing?
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From your description these conductors belong to the POCO and are not under NEC rules.

Roger
 
electrofelon

electrofelon

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That installation likely falls under 230.40 exception #2. Also see 230.2 indicating this would be one service.

Also, don't use the phrase "service feeders" it is an oxymoron.

The utility will not care if there are multiple sets of service conductors vs parallel service conductors.
 
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mull982

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Perhaps I am a bit confused then...what would be an example of where 230.90 would apply for service entrance conductors?
 
roger

roger

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The "Service Point" is where the NEC comes into play, the conductors before this belong to the utility.

Roger
 
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mull982

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roger said:
The "Service Point" is where the NEC comes into play, the conductors before this belong to the utility.

Roger
Click to expand...

So if the utility service comes down a pole through a utility owned transformer and continues into service entrance switchgear with utility metering then the conductors between transformer and switchgear are utility owned with no NEC requirement?

If the utility owns the transformer but has its metering installed in a cabinet on the transformer secondary then would the cables in this case become service entrance conductors? I'm just trying to come up with an example of when conductors would be considered Service Entrance per the NEC. Does it really come down to where the point of demarcation is with utility usually defined with utility metering?
 
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Hv&Lv

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mull982 said:
Are there any special requirements for having two service entrance feeders tapped from the same transformer? If an existing utility transformer has two separate SE feeders feeding two lineups located in the same building are there any special requirements outside of 230.90 for SE feeders? Do the tap rules of 240.21(C) apply here?

From what I can tell there are no special requirements for this case other than the standard requirements of 230.90 which would require these feeders only to have overload protection at the SE equipment they feed and be routed outside except for where they enter the building with no specific limitation on length for the outdoor routing?
Click to expand...



coming from the utility they are service conductors. As such, service conductors are unprotected which is why you are limited on how far they come inside a building.

230.90 says they must have overload protection at the point where the service conductors terminate, not originate.

even if the utility meters at a transformer secondary side and you install the conductors 200’(an arbitrary number) to the building, they are still service conductors and are unprotected until they reach their termination point. From there feeders and branch circuits are protected.
 
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