400amp 3-phase service

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Sam Moore

Sam Moore

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On a 400amp 240v 3-phase service can I and do I have to parallel the conductors between the meter and main? Also, can I use a common conduit nipple for the parallel conductors?
 
I beg to differ Larry. Well, "beg" maybe a little extreme. :)

On second thought, I agree, maybe. ;)

Sam, are you really an electician?

Roger
 
infinity said:
I agree with Larry. How long is the nipple? Using one nipple may lead to derating issues.
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A nipple joining the meter and panel is subject to derating? I cant remember if the nipple has to be over a certain length or not
 
Sam Moore said:
On a 400amp 240v 3-phase service can I and do I have to parallel the conductors between the meter and main? Also, can I use a common conduit nipple for the parallel conductors?
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Why do you need to parallel the conductors?
 
S_E_DInc. said:
A nipple joining the meter and panel is subject to derating? I cant remember if the nipple has to be over a certain length or not
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If the nipple is longer than 24" derating applies. Look at 310.15(2)(a)Ex.3.
 
Another closely related question, I did Industrial/Commercial applications for the the last 8 years and have been doing residential for a year and a half now. Some one was doing electrical work for a bar owner, and totally burned him, has romex running outside exposed pulled through steps outside and whatnot. Total hack job, anyways to my point, there are 2- 200 amp panels assuming its a 400 amp meter but only 1 4/0 sec service drop. The largest residential Service I have installed is 200 Amps, is it more practical to drop 2 4/0 sec's or an enourmous 600 ?

To be clearer on our intentions, who ever did it never got it inspected, the wires are still bugged outside, there are no ground rods or water, so we are going to make it code compliant, permitted and have it hooked it properly for the gentleman.
 
Jesse, is this 400A service for the bar owner's house or bar?

If it were parallel runs, it would be two CU 3/0 sets, not 4/0. I would go that route unless the meter socket's lugs couldn't accomodate parallel runs. I have yet to put in a 400A (at least, to a single residence), so I'm in the same boat you are. :)

Are you sure that the former installer even installed the overhead conductors? It could be that the POCO decided that a single 4/0 would be sufficient for a 400A service. They do goofy things like that. :D
 
georgestolz said:
If it were parallel runs, it would be two CU 3/0 sets, not 4/0.
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Maybe in Colorado.... Out here where it gets warm temperature derate can come into play, and I've seen and spec'd paralleled 250MCM CU for 400A service masts.

I see a lot of 400A services, and some 600A on single family houses in this area. The largest I've designed was 1200A, 3 phase. I have a 9500 s.f. detached "recreation room" addition for a single family residence in my office now that will have a 2 lane bowling alley, catering kitchen, and a recital hall that seats around 50. I'm expecting the service to be around 800A.

Martin
 
Good point George, it is his bar not his home so 4/0 aluminum would no longer apply correct, without my code book once again I am not sure but I believe 310.15 refers to 120/240v single phase dwellings ?

To put it in perspective.... it looks like he had a single 200 amp panelboard, and some fly by night electrician threw a second one in on the same 4/0 conductors, so the exsisting meter is probably a standard single line and load 200 amp meter. The only 400 amp installations I have seen for dwellings were direct burial that turned up in a ct cabnet, he has none of the above.

I appreciate the info, and will check my code book monday morning when I get to the truck, and get back to everyone, have a good weekend I am going fishing ;).
 
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Ok I got a little curious and started thinking about it, and believe I am gonna have run 2 pvc conduits up with weather heads for my drops of parrallel 3/0 copper or 250 aluminum. And might as well set a ct cabinet, but here inlies another problem, they set the panelboards over the freaking bar, not only does this violate 110.26 but possibly 240.24 I believe " looking at some notes I have, dont have my code book".

So now I may have to go with outside panelboards which would save time on the feeders but would be costly on branch circuits. I cannot believe some people can do stuff like this and sleep at night, this poor guy thinks they are taking care of him and instead they have possibly cost him thousands to make this catastrophy compliant.
 
hmspe said:
Maybe in Colorado.... Out here where it gets warm temperature derate can come into play, and I've seen and spec'd paralleled 250MCM CU for 400A service masts.
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Good point. I tend to think underground and forget about that sun. :)

kessler said:
...it is his bar not his home so 4/0 aluminum would no longer apply correct, without my code book once again I am not sure but I believe 310.15 refers to 120/240v single phase dwellings ?
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It's cool you know that section and rule on the top of your head - but I have to one-up you. It's 310.15(B)(6), off the top of my head. :D

Sounds like you've got it under control. :cool:
 
who's thread is this anyway ??? ...

who's thread is this anyway ??? ...

ay guys .. I do believe this was a post for Sam wasn't it ... if hmspe would like to ask a question kool but how about getting back to the original post ... what do you say ...

Sam Moore
Junior Member Join Date: Jul 2006
Posts: 1

400amp 3-phase service

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On a 400amp 240v 3-phase service can I and do I have to parallel the conductors between the meter and main? Also, can I use a common conduit nipple for the parallel conductors


thanks ... m
 
mario said:
ay guys .. I do believe this was a post for Sam wasn't it ... if hmspe would like to ask a question kool but how about getting back to the original post ... what do you say ...
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It's not OK to have a little fun?

Seriously, Jesse brought up something that was related to the original question, George responded, and I pointed out that there could be a bit more to the picture than George stated, then added a bit of personal experience that paralleled George's other comments. How is that a bad thing? Friendly discussions are common in these groups. If things get out of hand or too far off topic the moderators will step in -- that's their job.

Many of the questions posted in these groups are the wrong questions -- they tend to be too narrowly focused, or they make assumptions that are invalid. (ie., I frequently see feeders to residential sub-panels that are sized per Table 310.15(b)(6) because the electrician wasn't aware that the table only applies to feeders "that serve as the main power feeder to each dwelling unit".) The right answer to the wrong question is the wrong answer. Sometimes another person who's not quite as close to the problem can see a bigger picture, or we pick up on little things that the OP is missing. IMO exploring around the edges of the original question is usually a good thing.

Martin
 
Mario, I think the original post was answered. Jesse arguably should have started his own thread for his question, but it was along the same lines. No harm, no foul, IMO. :)
 
you rite guys ...

you rite guys ...

sorry guys .. didn't mean to sound the way it did ... I been on a roll lately in another thread and had a wierd attitude going ... I agree with both of you so carry on .... Have a Great Day

Speaking of Fishing ... the Silvers are starting to Run up here in Valdez ... they'll be jumping into boats in a few weeks ... oooppps, off the subject huh ... :rolleyes:
 
Yeah, I appologize for hijacking the thread, just noticed the title was pretty close to something on my mind and decided to have a look see :). I appreciate all the help and will get back with what we decide should be done.
 
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