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Service disconnect #215235 03/26/15 02:52 PM
Joined: Mar 2015
Posts: 2
M
Mitch65 Offline OP
New Member
Our guys are completing a job that another contractor started. It is a 1200A/600V service. we ran conduit from anew transformer pad to an existing electrical shack that was fed from a Generator. The shack has a 1200A unfused disconnect feeding a splitter that feeds 2 600A fused disconnects. Everything up to and including splitter is good for 1200A. Metering is transformer mounted. Do we need to swap out the 1200A unfused disconnect for a fused one? I say yes, inspector says maybe so far. He's going to get back to us.

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Re: Service disconnect [Re: Mitch65] #215236 03/26/15 03:50 PM
Joined: Mar 2004
Posts: 947
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twh Offline
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I think the 1200 amp splitter needs to be protected by 1200 amp fuses.

Re: Service disconnect [Re: Mitch65] #215237 03/26/15 06:01 PM
Joined: Jun 2004
Posts: 1,273
T
Tesla Offline
Member
"Metering is transformer mounted"

I've never seen that.

Please upload pictures to ECN.

In America the rules for the Poco and the User are different, as the Poco is not covered by the NEC.

"electrical shack"

Is this a mine?

The new conduit... is it a buried run?

In legalese, at which point does the installation become owned by the User?

In many situations, the demarkation point is the disconnect, itself... the location of the meter... not so important.

Every jurisdiction has its twists and turns on such matters. This is why they issue 'style sheets' // handbooks detailing E X A C T L Y how they want a (User's) Service to be laid out.

The few feet from the 1200A disconnect to the twin, fused, 600A disconnects may be considered covered under the tap rules.

In industrial situations, many of the hard rules are waived with the proviso that ONLY qualified personel will able to enter the electrical spaces.

It's as common as dust for Poco's to consider their underground secondaries suitably protected -- without fusing -- so long as they only stub out of the ground into suitable disconnecting means.

I've seen residental Services that featured twinned 200A panels feed by a 400A secondary -- with no unifying disconnecting means at all. This set up falls under the six OCPD rules.

Digging in frozen ground sounds like a real pain....









Tesla
Re: Service disconnect [Re: Mitch65] #215238 03/26/15 07:57 PM
Joined: Jun 2004
Posts: 610
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shortcircuit Offline
Member
We have 1 POCO that allows metering at the transformer here. They just install the CT donuts inside and mount the meter on the side of the transformer.

Another would put the CT donuts inside the transformer, but you have to mount the meter remote on pedestal or building.

On 480volt services, Cold Sequence is required for metering and on the smaller services, 320 meter or less the cold sequence disco doesn't require fuses...and isn't considered the Service Disconnect.

Re: Service disconnect [Re: Mitch65] #215260 03/30/15 02:35 PM
Joined: Mar 2015
Posts: 2
M
Mitch65 Offline OP
New Member
This service is for a "permanent" construction camp. It has been running on Generators for a year and we are doing the permanent hookup. The reason the disconnect was non fused was because the Gen has a main breaker so the original contractor thought they'd save a few bucks. Inspector Says disconnect must be fused as the consumer service starts at the meter(transformer). I would have included a picture but don't appear to have the mental faculties for that.
(PS digging in frozen ground does suck....but hydrovac trucks make it easier.. although messier).

Last edited by Mitch65; 03/30/15 02:38 PM.

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