# Three phase 120/240 1200amp overhead service



## Southeast Power (Jan 18, 2009)

I just had a thought about using a Ground Fault Breaker;

Section 230.95 requires solidly grounded Wye electrical services with main disconnecting means rated at 1,000A or more to be provided with GFPE where the voltage is more than 150V to ground but does not exceed 600V phase-to-phase. The setting of the GFPE must not be greater than 1,200A and the maximum time delay before operation shall not exceed one second (60 cycles) for ground-fault currents of 3,000A or greater.

My system is 120/ 240 open delta, with a high leg, usually 190 to 208 volts


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## Sparky Girl (Apr 15, 2015)

Thinking back on 1200A disconnects I've installed, all I can remember is the ones that were part of switchgear. IIRC, all of them were fused. Breakers didn't come into play until we dropped down to 600A but most still were fuses. It was more common to see breakers at 400A and below.

Sorry, but it's been 8 years since I retired and the cobwebs get thicker every year.


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## Southeast Power (Jan 18, 2009)

I usually see bolted pressure switches on the 2000 and up gear. Lots of 1200amp molded case breakers out there. If you are a retired union electrician and worked commercial and institutional projects during your career, You more than likely have thrown dozens of them and not realized the amperage. They are usually behind cover plates with just either the handle sticking out or one of the ones you have to pump a few times to load the spring.

See, I knew you would remember.


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## Cow (Jan 16, 2008)

Suncoast Power said:


> I wanted to just use a 1200 amp SE rated main but the guy supplying it, intends on maintaining it and has nothing good to say about SE rated ATSs.


What is his complaint?

We're ordering several 1200-2000 amp Siemens switchboards for a project right now and we're using breakered mains, if it matters.

We've never had an issue.


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## sbrn33 (Mar 15, 2007)

I would also go with the 1200 amp SE rated transfer switch. It makes a waaay cleaner job.


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