Does a 3-phase, 400A, NEMA 4X, 12-space panelboard exist?

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Calrissian45

Calrissian45

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I need a 3-phase, 400A, NEMA 4X panelboard. I need to keep it small and I only need to power three 3-phase breakers so I tried to find one that is 12-space. I can't fit a full 42-space panel in the location, but I can't find anything smaller. Are there any companies that will custom build this?
 
I don't know what you actually need from your description, but you could just put three breakers in a SS box, or three breakers and a main if you want a main.
 
On second thought, I'm not sure how I'd connect them all together on the line side. I'd need three lugs that can accept five wires each since the feeders are paralleled (i.e, 2 feeders and 3 breakers for each phase). Do they make bus bars for the line conductors like they do for the neutral and ground conductors? Or am I going the wrong direction?
 
Calrissian45 said:
On second thought, I'm not sure how I'd connect them all together on the line side. I'd need three lugs that can accept five wires each since the feeders are paralleled (i.e, 2 feeders and 3 breakers for each phase). Do they make bus bars for the line conductors like they do for the neutral and ground conductors? Or am I going the wrong direction?
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They make power distribution blocks.
You might want to look at having a UL508A panel shop do this rather than make it a DIY project.
 
I would find someone who has done one before, so you are not responsible for all the little details like what screws to use.
 
Calrissian45 said:
On second thought, I'm not sure how I'd connect them all together on the line side. I'd need three lugs that can accept five wires each since the feeders are paralleled (i.e, 2 feeders and 3 breakers for each phase). Do they make bus bars for the line conductors like they do for the neutral and ground conductors? Or am I going the wrong direction?
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Hint. Look and see what lugs are available for the breakers you want to use. You can often get lugs that have more holes than you might think. If you go the way of a UL508a shop they could use flexible bus bar. There are lots of options.

The biggest problem right now is getting breakers.

I think I spend almost as much time changing parts as anything else. Stuff is supposedly available when I order it and by the time I actually do order it I get an email from purchasing saying it's no longer available. The bane of my existence. At least right now.
 
I can't find it, but I recall something where a panelboard had to have its breakers connected to a busbar, terminal block and wires not allowed. Don't remember if I saw this in NEC or a UL standard. Or I could be completely wrong.

You didn't mention what size your branch breakers are. Also don't know what your dimension constraints are. There are some smaller I-line OEM interiors I wonder if you could get a panelboard made with one of those. A HFA225S4 is a single sided 400A bus and 23" long. Not sure if the subfeed lug and your branch breakers would fit on that.
 
Todd0x1 said:
I can't find it, but I recall something where a panelboard had to have its breakers connected to a busbar, terminal block and wires not allowed. Don't remember if I saw this in NEC or a UL standard. Or I could be completely wrong.

You didn't mention what size your branch breakers are. Also don't know what your dimension constraints are. There are some smaller I-line OEM interiors I wonder if you could get a panelboard made with one of those. A HFA225S4 is a single sided 400A bus and 23" long. Not sure if the subfeed lug and your branch breakers would fit on that.
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Okay, I'll look into that to be sure this doesn't violate a code or standard.

The breakers are 200A, 70A, and 20A. This is going on a trailer so the dimensions need to be as small as possible. An 18-space panel was originally specified and it fit the space well. It turns out that they don't exist in that size, though, so that's how I got here. A 42-space panel is too large.
 
Calrissian45 said:
Okay, I'll look into that to be sure this doesn't violate a code or standard.

The breakers are 200A, 70A, and 20A. This is going on a trailer so the dimensions need to be as small as possible. An 18-space panel was originally specified and it fit the space well. It turns out that they don't exist in that size, though, so that's how I got here. A 42-space panel is too large.
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Could you use two separate things? A 200a enclosed circuit breaker, and a little panel with the 70 and the 20?

What is the application on a trailer if you don't mind my asking?
 
How would the separate enclosures connect to a single source?

We're building an off-road trailer with a 400hz generator and environmental control unit to power and cool equipment on military training ranges. We couldn't find a generator that met our specs and had the outlets we needed so we're connecting it to a breaker panel to distribute the power to the equipment.
 
Calrissian45 said:
How would the separate enclosures connect to a single source?

We're building an off-road trailer with a 400hz generator and environmental control unit to power and cool equipment on military training ranges. We couldn't find a generator that met our specs and had the outlets we needed so we're connecting it to a breaker panel to distribute the power to the equipment.
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Glad I asked. 400hz brings in a new set of complications. Many panelboards and breakers are not rated for 400hz use, for example SQD QO is 50/60hz only. I-line can be used for 400hz but the breakers have to be re rated (they have a publication for this that I haven't read) not sure on other manufacturers.

Given the application, does this thing even have to be listed or NEC compliant? If not might want to go back to the idea of using panel mounted breakers in an enclosure with a power distribution block. Make sure everything is rated for 400hz. Eaton Heinemann breakers are commonly found on this sort of military gear.

Any buy america act requirements on the components used?
 
Hmm, I wasn't aware of that. I'm glad I mentioned it's 400hz.

That's where I've been confused about how to apply codes and standards. My experience is in building power and distribution power so this mobile system is pushing me into new territory. You have a good point, though.

Yeah, it has to be buy American. That always complicates things for us.
 
Calrissian45 said:
Hmm, I wasn't aware of that. I'm glad I mentioned it's 400hz.

That's where I've been confused about how to apply codes and standards. My experience is in building power and distribution power so this mobile system is pushing me into new territory. You have a good point, though.

Yeah, it has to be buy American. That always complicates things for us.
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Eaton heinneman GJ series is good for 400hz up to 250A

https://www.eaton.com/content/dam/eaton/products/electrical-circuit-protection/hydraulic-magnetic-circuit-breakers/eaton-heinemann-hydraulic-magnetic-circuit-breakers-br130001en.pdf
 
Many industrial style breakers work correctly in the thermal range, however their magnetic pickup is affected. This is often not a problem as many 400Hz sources do not produce a high amount of short circuit current.
 
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