200 amp service with 400 mcm

[iwire]

41, posts only one answering the the questions the OP asked.

Great job guys, pat yourself on the back.

BTW, moderator or not I am allowed to have an opinion.

 

[stickboy1375]

41, posts only one answering the the questions the OP asked.

Great job guys, pat yourself on the back.

BTW, moderator or not I am allowed to have an opinion.

Bob, you answered his question in the 2nd post, I dont see the problem in offering an easier solution to his question... IMO, there is no efficient way to connect 400 mcm to 200 amp panel and breakers. Not in the residential world anyway.

 

[buck33k]

what is most efficient way to connect 400 mcm to 200 amp panel and breakers?

Suggestion: Splice underground just beneath the meter base to reduce conductor size.

 

[ultramegabob]

200 amp meterbase on the pole....

200 amp meterbase on the pole....

under the meterbase install a W.P. fused disconnect with lugs large enough for 400 MCM and install 200 amp fuses. on the garage install a Milbank U4548XL distribution lug enclosure, and unless your able to reduce your wire size from the garage to the house, you will have to do some kind of reducing splice before the houses panel, possibly with a j-box and terminal block.....

im not saying this is a pretty install, but Im attempting to satisfy Bob.....

 

[Buck Parrish]

.

There are over a 1000 active members here,





That's what makes this forum fun. It is very active.
Lots of forums if you ask a question you may not get an answer for days.
That may be why some new poster may not stick around after he post.
Thinking he'll check back in a day or two.
Just my two cents.
But, I do enjoy the debates. Even if I am just reading and not involved.

 

[normbac]

(250' down the run
Total run is 500 sounds like a latteral to the garage at 250 ft. then 250 ft. to house question should be how did you determine wire size

 

[nate roach]

200amp service with 400mcm (james Cohee)

200amp service with 400mcm (james Cohee)

ok gents, here is the deal with the original posting. the meter is located about 25' from the service pole at the front of the property. from there 250' to the proposed garage site(not attached to house), then another 250' to the house. the reason for 200amps at the house is because there is an additional guest house and shop 60' from main house, and power for those will be supplied from the main house. there is no way that pg&e will let the home owner have 400a service, we have already tried that route. nothing is set in stone with this job as far as wire size/transformers, both are an option, but the whole reason for the job is to get the service underground, so we dont really like the idea of transformers, but with transformers you can go with a smaller wire size. FYI here 400mcm is 8.50ft. 600mcm Al is 2.50ft. thanks to all your feed back, now give some more!

 

[stickboy1375]

ok gents, here is the deal with the original posting. the meter is located about 25' from the service pole at the front of the property. from there 250' to the proposed garage site(not attached to house), then another 250' to the house. the reason for 200amps at the house is because there is an additional guest house and shop 60' from main house, and power for those will be supplied from the main house. there is no way that pg&e will let the home owner have 400a service, we have already tried that route. nothing is set in stone with this job as far as wire size/transformers, both are an option, but the whole reason for the job is to get the service underground, so we dont really like the idea of transformers, but with transformers you can go with a smaller wire size. FYI here 400mcm is 8.50ft. 600mcm Al is 2.50ft. thanks to all your feed back, now give some more!

Why does your POCO care about a 400 amp service? They either offer it or they dont? The other thing is what if the house actually needed a 400 amp service?

 

[ultramegabob]

Why does your POCO care about a 400 amp service? They either offer it or they dont? The other thing is what if the house actually needed a 400 amp service?

I was thinking the same thing:-?

 

[stickboy1375]

I was thinking the same thing:-?

Didn't want to sidetrack, but that really weirded me out.

 

[Buck Parrish]

You need a 400 amp service. The poco may increase the wire size a bit. But it does not have to increase any thing on their side. They base their wire size on the load. Not the NEC.
We are telling you 400 amp service for the quality of your installation.
It would be rediculous to install 400 cu. mcm to a 200 amp service.
In fact the direct burial Aluminum has a tougher insulation. Therfore you are less likely to get a insulation failure.

 

[nate roach]

Why does your POCO care about a 400 amp service? They either offer it or they dont? The other thing is what if the house actually needed a 400 amp service?


ok, 400a service is not offered, and the main house will only need a 100 amp sevice.

 

[iwire]

You need a 400 amp service.

With out knowing the actual calculated load it is imposable to say he needs a 400 amp service.

The poco may increase the wire size a bit. But it does not have to increase any thing on their side. They base their wire size on the load. Not the NEC.

I agree with that, but what the power company does is not our concern

We are telling you 400 amp service for the quality of your installation.

And I am telling you that we can't say a 400 amp service is needed or better without a calculated load.

That is not an opinion it is a fact.

It would be rediculous to install 400 cu. mcm to a 200 amp service.

No, not ridiculous, it's called designing to prevent voltage drop.

In fact the direct burial Aluminum has a tougher insulation. Therfore you are less likely to get a insulation failure.

Which is also irrelevant as he is running conduit.

 

[iwire]

ok, 400a service is not offered, and the main house will only need a 100 amp sevice.

And again how the heck can you say that without knowing the calculated load?

 

[Smart $]

With out knowing the actual calculated load it is imposable to say he needs a 400 amp service.

I agree. Design the system based on calculated load, consider adding a little for future additional loads, and there it is. What meter base and what amperage the service is of little concern in this regard.

In fact the direct burial Aluminum has a tougher insulation. Therfore you are less likely to get a insulation failure.

Which is also irrelevant as he is running conduit.

Not totally irrelevant... as OP'er said, nothing set in stone.

I personally prefer the transformer route... but I get the impression money is not the major concern here to the HO... rather they are being persnickety on appearance, giving it a higher priority!!!

 

[nate roach]

we cannot do a direct burial, in has to be in conduit. and money is a concern, were in a recession. the reason for 400mcm is for the voltage drop, this is an expensive route, but transformers are not cheap either(2 needed). apperance is a concern(transformers above ground) anything above ground can be knocked out by trees(it happens every year), and this is what we are trying to avoid. it seems were in a pickle! big wire or transformers?

 

[winnie]

You have other options.

For example, the utility could provide an underground primary feed to a pad mount transformer located between the buildings. This would involve higher voltage and much less copper...but is often an expensive installation.

You may be able to go the transformer route, but convince the utility to supply you with higher initial voltage, eliminating one of the transformers. Starting with 480V and then stepping down to 240V is much better than 240->480->240.

You may be able to use a voltage regulating transformer to supply only those loads that are particularly sensitive to voltage drop.

You may be able to convince the AHJ to permit the use of _two_ feeders, one for bulk loads (HVAC, for example) , one for sensitive loads (lighting).

If you go the transformer route, don't forget about 'transformer impedance', the voltage drop built into the transformer itself.

-Jon

 

[petersonra]

i am installing underground 200 amp service. the run to house is 500'. proposed garage is approx 250' down the run. as most of the load is in the garage it will have 200 amp panel. from there we will continue to the house to another 200 amp panel. wire size is 400 mcm cu. what is most efficient way to connect 400 mcm to 200 amp panel and breakers? is there a 200 amp panel that accepts 4" conduit on the bottom? breakers? my partner wants to use transformers to reduce conductor size but customer is not too keen on them.

I think Ilsco makes some insulated connectors you could crimp on that mate a large and small wire.

I think your partner has the right idea though.

Are you planning a disconnect and ground at the point it goes underground?

 

[Smart $]

we cannot do a direct burial, in has to be in conduit. and money is a concern, were in a recession. the reason for 400mcm is for the voltage drop, this is an expensive route, but transformers are not cheap either(2 needed). apperance is a concern(transformers above ground) anything above ground can be knocked out by trees(it happens every year), and this is what we are trying to avoid. it seems were in a pickle! big wire or transformers?

Falling trees generally do not take out transformers. Mostly, they take out the lines connected to them. And this is regarding pole mounted ones. It likely has occured somewhere, at some time, but I've never heard of a tree taking out a pad mount transformer or the underground lines connected to it.

 

[benaround]

I'd just get a big wood burning generator.