designer

[RETKWA]

I have a 1500KVA substation 12.47V Pri 277/480V Sec. Primary side is fused @ 80A the question is, am I limited to (6) circuit breakers in the secondary distribution section?

 

[jim dungar]

I have a 1500KVA substation 12.47V Pri 277/480V Sec. Primary side is fused @ 80A the question is, am I limited to (6) circuit breakers in the secondary distribution section?

Your secondary conductors need to be protected by one the the 'options' in 240.21(C) unless you have a Supervised Industrial Installation, used exclusively for manufacturing or process control, in which case you need to comply with 240.90.

For most installations, it is safe to assume you will be restricted to 6 devices.

 

[augie47]

Keep in mind also, unless you can meet one of the exceptions, 225.30 limits you to one feeder per building and 230.2 limits you to one service per building.

 

[charlie b]

You could instead have one main breaker serving the main switchboard. Then there would be no limit to the number of breakers you can put into the main switchboard to serve downstream loads. I tend to prefer to do it this way.

 

[ron]

You could instead have one main breaker serving the main switchboard. Then there would be no limit to the number of breakers you can put into the main switchboard to serve downstream loads. I tend to prefer to do it this way.

I often do it this way too, but then you need GFP. If you put (6) smaller distribution breakers / fuses (<1000A), then you save some headache and cost.