Service Laterals vs Service Conductors

[gporter]

Here is the situation. This is a commercial compound of 6 separate buildings. There is a central POCO transformer, and each building is to be supplied from this transformer by buried service entrance conductors, each building has its own disconnect and grounding. The owner would like one meter to cover all buildings, and POCO can supply CT metering at the transformer. One set of service lateral conductors will come out of the transformer, through the CT meter, and to large ?Polaris? connectors where the services to the various buildings are tapped.

The question is ? Is it true that once the service LATERAL goes thru the meter transformer coils they become service entrance conductors and not laterals? NEC 230.40 says that each service lateral shall supply only one set of service entrance conductors. So now we can?t split out to feed six separate buildings. However, if we had separate meters at each of the buildings, it would be considered six separate service laterals, and everything would be OK. Why does moving the metering point to a central location change anything?

Thansks, Greg

 

[Smart $]

...Why does moving the metering point to a central location change anything?

It's not the metering point that changes the defined purpose of service conductors... it is to what and where they are terminated. In my book CT metering is not a termination, but I'm open to correction. As such, you have a service lateral to the "Polaris" connector. The conductor sets from this connector to each building are service entrance conductors (SEC's)... provided the disconnecting means are internal to the structures. If the disconnects are external to the buildings, these sets would be service laterals (and there would be no SEC's).

Or, if you eliminated the "Polaris" connector and terminated each building's supply conductors to the transformer terminals, after passing through the CT's, you would have six service laterals. These laterals would become SEC's when, and if, they penetrate the shell of the respective structures... but the requirement 1SL to 1SEC is met.

 

[George Stolz]

I'd say there is no rock-solid answer to this question. From a practical standpoint, you must get together with the POCO and the AHJ to figure out the appropriate way to feed these buildings that everyone can agree with.

 

[don_resqcapt19]

Exception #1 to 230.40 would permit this installation.
Don

 

[gporter]

not sure I follow you here:

The conductor sets from this connector to each building are service entrance conductors (SEC's)... provided the disconnecting means are internal to the structures. If the disconnects are external to the buildings, these sets would be service laterals (and there would be no SEC's).

I don't see where the disconnecting means located inside or outside of each building would make a difference. If the "termination" at the polaris conductors is the demarcation line between service laterals and service conductors, then the conductors to each building would be considered service entrance conductors, and thus violate 230.40.

The diagram at the beginning of Article 230 shows the demarcation line as the "terminal box, meter, or other enclosure". So it looks like the answer depends on where this demarcation point is determined to be. I guess, as George says that it would be best to get the POCO and AHJ get together and make the call. I would like to avoid having to put in additional disconnects and likely an additional equipment grounding conductor to each building, which I would have to do if it turns out that the buried conductors to each building can not be considered service laterals.

 

[gporter]

Exception #1 to 230.40 would permit this installation.
Don

I guess it would if we could say that the six different, separate, buildings can be considered as "A building with one or more than one occupancy...".

 

[Smart $]

I don't see where the disconnecting means located inside or outside of each building would make a difference.

If the service disconnecting means are outside the buildings, the service conductors from the multi-tap connector to the switches do not "enter" the structures. If no service conductors enter the structure served, there are no service "entrance" conductors. This determines what the other non-POCO sections of the underground service will be dubbed.

The diagram at the beginning of Article 230 shows the demarcation line as the "terminal box, meter, or other enclosure". So it looks like the answer depends on where this demarcation point is determined to be.

Is the connector in an enclosure or is it direct-buried? If you direct bury it (provided it's listed for direct burial), you have service laterals. With the connector in an enclosure, the tap conductors are open to being called SEC's.

 

[eprice]

If no service conductors enter the structure served, there are no service "entrance" conductors. This determines what the other non-POCO sections of the underground service will be dubbed.

Looking at the definitions in Article 100, I can't see any requirement that these conductors enter a building in order to be called service entrance conductors. If there were no CT meter and polaris connectors to serve as a "fisrt point of connection" then the last sentence in the definition of "Service Lateral" would seem to require entry into a building. But, as described in the OP, there is a point of connection between the service lateral and the service entrance conductors at the CT enclosure.

 

[Smart $]

Looking at the definitions in Article 100, I can't see any requirement that these conductors enter a building in order to be called service entrance conductors.

I suspected someone would bring this up... and you are correct. The FPN after the defintion of Service Entrance Conductors really opens the door where it states, "...or they (SEC's) may be entirely outside the building." As such, this certainly leads to more ambiguity than to take the phrase solely on its literal meaning. I believe the definition of Service Entrance Conductors is relaxed just enough so that all service conductors between a service drop and the service disconnecting means are included, even when the disconnecting means is external... and that, IMO, unintentionally bleeds over into service laterals. It all goes back to why a section of service conductors were called service entrance conductors to begin with. Nevertheless, a debate limited to the text of the NEC will not yield a winner.

As it is though, all I can do is throw a log on the fire...

If each service drop or lateral shall supply only one set of service entrance conductors (230.40), why are service laterals permitted to be tapped (230.66)? I know someone will say for monitoring, surge, and such equipment, but is that the only and ultimate purpose for permitting taps? ...and just exactly what do we call these tap conductors?

If there were no CT meter and polaris connectors to serve as a "fisrt point of connection" then the last sentence in the definition of "Service Lateral" would seem to require entry into a building.

That's what I said earlier, with the exception conductor-pass-through CT metering is not a connection point.

But, as described in the OP, there is a point of connection between the service lateral and the service entrance conductors at the CT enclosure.

I see the "point of connection" at the "Polaris" connectors, not the CT enclosure (if there is one... all the transformer CT metering I've dealt with puts the coils over the terminal bus of the transformer secondary).