Need info: 1200 amp 480/277V disconnect

[charlie b]

I only need round numbers. What would be the likely dimensions (H, W, D), the weight, and the cost (material only) of an outdoor-rated,1200 amp, 480/277V disconnect? It would be installed on a pad adjacent to the pad for the utility transformer. Alao, since the service switchboard would be some distance away on its own outdoor pad, would the disconnect need to be fused?

 

[tom baker]

What is the disconnect for?

 

[don_resqcapt19]

The disconnect will be the service disconnect, and will need to have fuses. Even if you find away to not have the disconnect be the service disconnect, you will still likely need fuses as most non-fused disconnects have a SCCR of 10kA.
List price shows at about $20k

Depth	17.75 in (450.85 mm)
Width	36.62 in (930.15 mm)
Height	69.13 in (1755.90 mm)
Net Weight	382.06 lb(US) (173.3 kg)

 

[charlie b]

What is the disconnect for?

"Convenience."

There will be a significant delay between setting the utility transformer and installing the service lateral and everything else downstream. The PM is hoping that having their own disconnecting means immediately adjacent to the transformer will allow the contractor to energize the system without having to wait for the utility to turn off then turn on their transformer. Whether or not PSE will go along with this idea is yet to be seen.

 

[augie47]

Would GF protection not have to be addressed ? Raises cost considerably

 

[charlie b]

Would GF protection not have to be addressed ? Raises cost considerably

I think not, based on 240.13. It would not be the main disconnecting means for a building or structure.

 

[charlie b]

The disconnect will be the service disconnect, and will need to have fuses.

I agree. 240.21(C)(4)(2).

 

[don_resqcapt19]

I think not, based on 240.13. It would not be the main disconnecting means for a building or structure.

It will be the service disconnect and 230.95 will apply in my opinion.

 

[electrofelon]

I agree. 240.21(C)(4)(2).

I disagree. 240.21(C) is not for utility transformers. 230.91 would be your section.

 

[kwired]

If purchasing as stand alone item I'd expect different price than if purchased with the mentioned switchboard that it is supplying.
These manufacturers like to sell items by the job and you get different pricing when purchasing the whole job than if you purchased every item as a separate purchase, usually much better pricing. You likely don't get line item pricing on such orders but the lump sum is still much less than separately purchasing all the items.

 

[electrofelon]

"Convenience."

There will be a significant delay between setting the utility transformer and installing the service lateral and everything else downstream. The PM is hoping that having their own disconnecting means immediately adjacent to the transformer will allow the contractor to energize the system without having to wait for the utility to turn off then turn on their transformer. Whether or not PSE will go along with this idea is yet to be seen.

That's a lot of expense for a one time convenience

 

[Jraef]

The disconnect will be the service disconnect, and will need to have fuses. Even if you find away to not have the disconnect be the service disconnect, you will still likely need fuses as most non-fused disconnects have a SCCR of 10kA.
List price shows at about $20k

Depth	17.75 in (450.85 mm)
Width	36.62 in (930.15 mm)
Height	69.13 in (1755.90 mm)
Net Weight	382.06 lb(US) (173.3 kg)

That’s for a 1200A fusible “safety switch”, aka knife switch. 1200A is the upper limit of that technology.

If you need GF protection, you need a switch that can be fitted with a shunt trip, so it becomes a “bolted pressure switch” (BPS), also known as a “Pringle Switch”. That will run you about $90k, figure 40W x 36D x 92H.

 

[charlie b]

The issue has gone away. PSE, understandably, won't go along with the idea of providing power to a disconnect switch before their metering is installed in the downstream switchboard (scheduled to take place many months later).

One more question: if there was a disconnect immediately downstream of the transformer, would I be right in saying the wires from the transformer to the disconnect comprise a "service lateral" and the wires from the disconnect to the switchboard comprise a "feeder"?

 

[david luchini]

The issue has gone away. PSE, understandably, won't go along with the idea of providing power to a disconnect switch before their metering is installed in the downstream switchboard (scheduled to take place many months later).

One more question: if there was a disconnect immediately downstream of the transformer, would I be right in saying the wires from the transformer to the disconnect comprise a "service lateral" and the wires from the disconnect to the switchboard comprise a "feeder"?

Around here there service point would be the transformer terminals...

The wires from the transformer to the disconnect would be service entrance conductors.

The wires from the disconnect to the switchboard would be a feeder.

 

[don_resqcapt19]

The issue has gone away. PSE, understandably, won't go along with the idea of providing power to a disconnect switch before their metering is installed in the downstream switchboard (scheduled to take place many months later).

One more question: if there was a disconnect immediately downstream of the transformer, would I be right in saying the wires from the transformer to the disconnect comprise a "service lateral" and the wires from the disconnect to the switchboard comprise a "feeder"?

The conductors on the load side of the disconnect would be feeder conductors. The conductors between the transformer and the disconnect would be either service laterals or underground service conductors depending on the location of the service point.