Parallel Utility Transformers for Service

[augie47]

These are not transformer secondary conductors, they are service conductors.

Great Point ! Would 230.90 not the apply and the install be a violation ?

 

[electrofelon]

Great Point ! Would 230.90 not the apply and the install be a violation ?

I could see that being a possibility. I guess it comes down to ones philosophy on whether the POCO equipment is a black box that is none of your concern

 

[synchro]

Since the utility will not take ownership of the conductors under discussion, I agree that the transformer side of these conductors will be a service point and therefore they will be "service conductors." But it appears the POCO is actually providing two service points (one for each of two services) because they are isolated from each other and have no electrical connection to each other. As far as I can tell the customer needs only one service in accordance with the NEC which can be protected by a single OCPD. Having the POCO connect the two transformers secondaries in parallel will eliminate these issues.

 

[bwat]

I could see that being a possibility. I guess it comes down to ones philosophy on whether the POCO equipment is a black box that is none of your concern

I could see that one as being the one to use here. I had posted it in post #15 as an option, but was uncertain on applicability.

230.90:

Part VII. Service Equipment — Overcurrent Protection
230.90 Where Required. Each ungrounded service conductor
shall have overload protection.
(A) Ungrounded Conductor. Such protection shall be provided
by an overcurrent device in series with each ungrounded
service conductor that has a rating or setting not higher than
the allowable ampacity of the conductor. A set of fuses shall be
considered all the fuses required to protect all the ungrounded
conductors of a circuit. Single-pole circuit breakers, grouped in
accordance with 230.71(B), shall be considered as one protective
device.

 

[bwat]

Since the utility will not take ownership of the conductors under discussion, I agree that the transformer side of these conductors will be a service point and therefore they will be "service conductors." But it appears the POCO is actually providing two service points (one for each of two services) because they are isolated from each other and have no electrical connection to each other. As far as I can tell the customer needs only one service that can be protected by a single OCPD. Having the POCO connect the two transformers secondaries in parallel will eliminate these issues.

Agreed. It is almost like two services to a single OCPD.

I'll go for another round of discussions with them and bring up these topics with confidence now that I know I'm not just being overly cautious here and making an issue out of something that isn't one.

 

[petersonra]

IMO, the utility gets to decide where the demarcation point is.

They can also run the wires to that point or have you run them. They are still under their jurisdiction regardless of who puts them in.

The NEC only applies downstream of the demarcation point. What the utility chooses to do upstream of that point is up to them.

 

[bwat]

IMO, the utility gets to decide where the demarcation point is.

They can also run the wires to that point or have you run them. They are still under their jurisdiction regardless of who puts them in.

The NEC only applies downstream of the demarcation point. What the utility chooses to do upstream of that point is up to them.

Thanks, I think that all sounds consistent with the general consensus here

 

[bwat]

Good news. It's nice working with a friendly utility. After going deeper into describing the issues we were facing with the utility and proposing the alternate solutions, the utility liked the idea of calling the line side of the main CB the demarc but the owner still installing those line side conductors. That will be the plan.


This triggers a related question for me though. Are there any restrictions on where the demarcation point is allowed to be? This almost seemed too easy to move it into the building to the line side CB terminals. Would there be anything stopping me from going further? Just theoretical.

 

[kwired]

Since the utility will not take ownership of the conductors under discussion, I agree that the transformer side of these conductors will be a service point and therefore they will be "service conductors." But it appears the POCO is actually providing two service points (one for each of two services) because they are isolated from each other and have no electrical connection to each other. As far as I can tell the customer needs only one service in accordance with the NEC which can be protected by a single OCPD. Having the POCO connect the two transformers secondaries in parallel will eliminate these issues.

I like this, they are supplying two service points for something that needs one service point. A common bus close to each secondary is just good design in this sort of situation.