Service Entrance to Building - Exterior Disconnect?

[death900]

Im trying to understand the requirements for service entrances.

If im running cables from a padmount transformer outside the building, underground inside the building, it must terminate on an OCPD closest to the transformer on the inside of an exterior wall for instance.

When reviewing the code, there are implications for underground and overhead cables. If the cables run from the transformer through a trench, that is considered overhead as i understand it from a code perspective.

My question is if the cables are run overhead, would a disconnect need to be provided on the exterior of the building before the cables enter the building?

 

[infinity]

What type of building?

 

[tom baker]

Typically an exterior disconnect is not required in my area, but as pointed out the building occupancy may require one. Your POCO may require one, do you have their handbook?
Sometimes is preferable to have the service disconnect inside in a dedicated electrical room.
We are required to have a utility disconnect ahead of the meter for a 200 amp and under 277/480 service.

 

[death900]

Typically an exterior disconnect is not required in my area, but as pointed out the building occupancy may require one. Your POCO may require one, do you have their handbook?
Sometimes is preferable to have the service disconnect inside in a dedicated electrical room.
We are required to have a utility disconnect ahead of the meter for a 200 amp and under 277/480 service.

Do you know off hand what occupancy types would require service disconnect to be on the exterior?
Im not sure what the occupancy classification would be, but for sake of argument commercial building maybe data processing.

 

[infinity]

Do you know off hand what occupancy types would require service disconnect to be on the exterior?
Im not sure what the occupancy classification would be, but for sake of argument commercial building maybe data processing.

One and two family dwellings require an emergency disconnect on the outside. Unless a meter disconnect is required by the POCO you don't need one outside.

 

[jaggedben]

...

When reviewing the code, there are implications for underground and overhead cables. If the cables run from the transformer through a trench, that is considered overhead as i understand it from a code perspective.

A trench would be underground. (Typo?)

My question is if the cables are run overhead, would a disconnect need to be provided on the exterior of the building before the cables enter the building?

Overhead vs. underground does not change disconnect location requirements. See 230.70(A) for the requirements. See also 230.85 (emergency disconnect) if the building is a one or two family dwelling. If routing conductors under the building, see 230.6 for where they are considered to enter the building.

 

[death900]

Thanks everyone. A previous company i worked for an engineer above me said that we needed a disconnect outside the building due to service entrance requirements. I never challenged it, but it doesnt seem like its needed for a commercial building (non-dwelling unit).

 

[infinity]

Thanks everyone. A previous company i worked for an engineer above me said that we needed a disconnect outside the building due to service entrance requirements. I never challenged it, but it doesnt seem like its needed for a commercial building (non-dwelling unit).

That's correct.

 

[tom baker]

Thanks everyone. A previous company i worked for an engineer above me said that we needed a disconnect outside the building due to service entrance requirements. I never challenged it, but it doesnt seem like its needed for a commercial building (non-dwelling unit).

You are wise to question someone. Codes change, POCO rules channge. And ask here as we all learn