200a + 100a Cut-offs On 200a Service

ndavid79

Is it ok to parallel a 100a cut-off switch to a 200a cut-off on a 200amp meter base, like in included diagram?

Thanks!

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Speedy Petey

ABSOLUTELY NOT. You would need a trough under the meter to make those splices. You CANNOT make splices in the meter pan and you cannot double lug a meter pan with single lugs.


BTW, in you drawing above (very nice I must say) the green wire should be white. I know the background is white, but I thought I'd mention it.

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Speedy Petey

Oh, to answer the questions in blue.
The neutral would get bonded in both disconnects, and a 3-wire feeder run to the buildings. This is unless you are under the 2008 NEC, in which case a 4-wire feeder must be run.

Actually since this is a trailer there should be a 4-wire feeder to it also. I don't think it was ever legal to run a 3-wire feeder to a trailer.

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mdshunk

I need to disagree with Peter, at least for a little bit here, which I don't think has ever happened. You can put Polaris bugs in the meter can to do what you want if there's room in the meter can. I'd use bigger Polaris bugs than you show so that the run wire that you're tapping can accomodate a 4/0 or a 250 MCM. Just don't double lug the meter can's lugs. There may be power company rules against Polaris bugs in the meter can, in which case you'll need a trough like Peter describes.

thom

It looks like your set-up would allow a 300A draw through a 200A meter base. You don't give us the service wire capacity but it's probably overloaded also.

mdshunk

Not if he did a calc. That setup is 100% legal if the calc shows less than 200 amps. You could connect a million amps worth of "mains" off a 200 amp meter can as long as your calculated load was less than 200 amps.

thom

Interesting. Here, we supply the wire in an overhead mast (the poco supplies the wire in an underground feed). The wire size we must supply is determined by the overcurrent device(s) installed.

Your scenario, sizing based on calculated load, assumes that additional loads will not be imposed even though you have provided for that possibility. That seems like a dangerous assumption to me. Our PoCo would not allow it.

Maybe that's the difference. Not only are we required to meet the NEC rules but also the PoCo rules. They provide us with a book detailing their installation requirements. If we don't meet their requirements, they won't connect us up.

Magnettica

If I have (25) 15 amp circuit breakers, and (15) 20 amp breakers, doesn't that mean I need a 675 amp panel?

Ha ha - just kidding.

kbsparky

Why not use a feed-thru panel, or better yet, a combo meter/service/feed-thru box?

One such panel would look like this:



You can merely plug in your 100 Amp breaker for the garage feeder.

ndavid79

Thanks everyone for your help/comments... So it is ok to do that if spliced properly? (would never double up wire in a single lug, thats just askin for trouble) I really thought it wasn't. Ok, would it be better to do the splice in the Trailer disconnect box (much more space in there)?
I do plan to go with next size up (250) polaris bugs.

Thanks!

acrwc10

What you are asking about is not a "parallel" but a "Tap". I doubt the utility co. will allow a tap in there meter can but as Marc and Pete pointed out a trough under it and you are fine. You will need to do a load calculation using article 220 of the NEC, you can't just "wing it". And brush up on article 250 on how you are going to ground/bond the structures.