Service Conductors and Service Entrance Conductors

[infinity]

For the sake of discussion let's use the overhead definitions. I admit I occasionally use these two terms interchangeably but do we really need to two separate definitions?

 

[Dennis Alwon]

It would seem that they are the same conductors in some instances but can be different--It may make sense in terms of code rules where this difference can affect the interpretation.

 

[electrofelon]

For the sake of discussion let's use the overhead definitions. I admit I occasionally use these two terms interchangeably but do we really need to two separate definitions?

Good question. I am not sure what the purpose of separately defining the two is. The 230.40 are for SEC, but the statement in 230.2 effectively expands 230.40 ex 2 to service conductors as well.

 

[LarryFine]

Maybe "entrance" refers to the building penetration.

 

[electrofelon]

Maybe "entrance" refers to the building penetration.

Yes, and that is considered the point of transition where there is no meter or terminal box. But the question remains: do we need to distinguish?

 

[wwhitney]

Well, just from reading (2017) Article 230 Parts I through IV, one difference between service conductors and service entrance conductors is that the latter are sized to include a 125% factor for continuous loads (230.42(A)(1)). Whereas service conductors are only sized for the load calculated according to Article 220, which has no reference to any 125% factor for continuous loads. (230.23(A) or 230.31(A)).

So if I understand correctly, for the 2020 NEC (assuming no relevant changes), for a residential service with a calculated load of 200A, of which 100A is continuous, you could have the following arrangement:

Service Drop (conductors sized by utility)
Service Point (point of attachment to the structure)
Overhead Service Conductors (200A ampacity)
Outdoor Meter/Emergency Disconnect (200A)
Service Entrance Conductors (225A ampacity)
Indoor Main Breaker Service Panel (225A)

Cheers, Wayne