Disconnect upstream from the Service Entrance Disconnect

[diakonos1984]

I'm working on an existing large telco building in a downtown metropolitan environment. The electrical service (480V) enters the building through a below-sidewalk vault via cable. Once inside the building it transitions to horizontal bus duct, and goes up to the first floor to the main breaker, which serves as the Service Entrance Disconnect. It's a long distance, but the NEC handbook says under 230.70(A) that there is no maximum distance specified in the NEC.

I'd like to install a non-fused switch between the cable and the bus duct. Purely for isolation in the event that the horizontal bus duct requires repair. I don't want any automatic operation of this disconnect. No overcurrent.

I DON'T WANT to move the service disconnect point. Is there anything in the NEC preventing me from installing a non-fused disconnect upstream of the Service Entrance Disconnect? I haven't found anything that defines the Service Entrance Disconnect as the first disconnect downstream from the utility...

 

[JoeStillman]

See 230.82. You can put it there if it's upstream of the meters. Otherwise, your new switch would just be the new service disconnect. You would have to have overcurrent protection though, or else have some kind of interpretation of "adjacent" that gets you past 230.91. Also, the new service disconnect would have to have a main bonding jumper and the old one would have to have it removed.

 

[diakonos1984]

That's what I was looking for! Thanks for the prompt response!

 

[don_resqcapt19]

See 230.82. You can put it there if it's upstream of the meters. Otherwise, your new switch would just be the new service disconnect. You would have to have overcurrent protection though, or else have some kind of interpretation of "adjacent" that gets you past 230.91. Also, the new service disconnect would have to have a main bonding jumper and the old one would have to have it removed.

You may have to work that out with your utility...the only disconnect our utility will permit on the line side of their meter is a meter disconnect that they require. They only require meter disconnect for self contained 480 volt meters, so a disconnect on the line side of the meter would not be an option under our utility rules.

 

[augie47]

"It's a long distance,
"
I'm surprised the install is acceptable to the AHJ !