Service conductors outside

[hhsting]

I don’t see in NEC 2017 Article 230 where it says service conductors must be outside? I have engineer challenging and has routed service conductors inside but i don’t see anything in NEC 2017 that says service conductors must be outside

 

[infinity]

They can be inside but they must hit the service disconnect nearest their point of entry into the structure. That limits how much can be within the building before the service disconnect.

 

[hhsting]

They can be inside but they must hit the service disconnect nearest their point of entry into the structure. That limits how much can be within the building before the service disconnect.

Any section in NEC 2017 for the above?

 

[charlie b]

I have seen the rare instances in which the utility transformer is in the building's basement. In those installations, the service conductors are certainly completely inside. In all other installations, the service conductors are necessarily outside for at least part of their length. So it is not clear to me what your engineer is challenging nor what issue you are trying to describe.

You can have the service disconnecting means on the outside wall, in which case the service conductors are completely outside. From that point into the building, you no longer have service conductors; you have a feeder.

You can have the service disconnecting means inside the building (see Infinity's comment), in which case the service conductors are partly outside and partly inside.

 

[wwhitney]

Any section in NEC 2017 for the above?

Go to Article 230 (Services)
Read the diagram at the beginning--Part VI is "Disconnecting Means".
Start reading there--it's in the very first section of Part VI.

Cheers, Wayne

 

[don_resqcapt19]

I have seen the rare instances in which the utility transformer is in the building's basement. In those installations, the service conductors are certainly completely inside. In all other installations, the service conductors are necessarily outside for at least part of their length. So it is not clear to me what your engineer is challenging nor what issue you are trying to describe.

You can have the service disconnecting means on the outside wall, in which case the service conductors are completely outside. From that point into the building, you no longer have service conductors; you have a feeder.

You can have the service disconnecting means inside the building (see Infinity's comment), in which case the service conductors are partly outside and partly inside.

Very common in Chicago, and for the high rises, the utility medium voltage distribution runs to utility transformers on multiple floors, not just the basement.

 

[suemarkp]

Not sure if its the same section in 2017, but a work around is in 230.6 "Conductors Considered Outside the Building."

 

[Fred B]

Not sure if its the same section in 2017, but a work around is in 230.6 "Conductors Considered Outside the Building."

same in 2017

 

[suemarkp]

Also, see if your state has defined how far service conductors can come into a building before hitting the disconnect. Here in WA, that limit is 15 feet. If no state or local modification of the NEC, then it is "nearest point of entry" which is as soon as penetrates the building envelope (unless you use the concrete trick in 230.6).

 

[infinity]

Very common in Chicago, and for the high rises, the utility medium voltage distribution runs to utility transformers on multiple floors, not just the basement.

Common also in NYC also but the conductors although inside are typically run to comply with 230.6 which makes them technically outside.

 

[Fred B]

They can be inside but they must hit the service disconnect nearest their point of entry into the structure. That limits how much can be within the building before the service disconnect.

The issue that commonly comes up is that this condition is open to interpretation of the AHJ to determine "nearest to point of entry" 230.70(A)(1). Some say 6ft, some say 10 or 15ft, others indicate not more that 3 ft inside of building.

 

[don_resqcapt19]

The issue that commonly comes up is that this condition is open to interpretation of the AHJ to determine "nearest to point of entry" 230.70(A)(1). Some say 6ft, some say 10 or 15ft, others indicate not more that 3 ft inside of building.

And I say nearest means exactly that...you come through the wall and directly into the service equipment or directly up or down into the service equipment.
However our local amendment to the NEC permits 10' of service conductor inside the building, but it also requires service conductors to be in RMC or IMC.

 

[augie47]

Not sure if its the same section in 2017, but a work around is in 230.6 "Conductors Considered Outside the Building."

You might also want to reference 230.70(A)(1)

 

[suemarkp]

You might also want to reference 230.70(A)(1)

Don't see how that changes anything if encasing in concrete says the conductors are outside the building. As soon as concrete encasement stops, they are inside the building and you need to have the disconnect right there.

 

[augie47]

I wasn't disagreeing with your reference but was simply giving him another reference as to where the service disconnect needs to be in relation to the service conductors once they are considered inside.
My comment was meant only as added information not contrary to your post.

 

[tom baker]

Also, see if your state has defined how far service conductors can come into a building before hitting the disconnect. Here in WA, that limit is 15 feet. If no state or local modification of the NEC, then it is "nearest point of entry" which is as soon as penetrates the building envelope (unless you use the concrete trick in 230.6).

And WA restricts the type of raceway inside the building

 

[charlie b]

Here is my understanding: This whole business is all about trying prevent the building from catching fire if the service conductors are somehow damaged. They have no overcurrent protection upstream of the service disconnecting means, so a short circuit could go on for a while. If that happens outside, the building won't catch fire. But if the disconnect is inside, you limit the distance in order to limit the opportunity for something to damage them.