Wiring Using Busbar

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Electriman

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Greetings,

I am working on a project where I need to run insulated copper busbars to feed the load. I know in the normal world, I can buy the busduct to for this purpose but due to the cost, I've decided to buy the individual insulated busbars to run to the load. Now I am facing a couple challenges:
a. What is the position of the NEC in busbar wiring
b. What are the minimum safety requirement that I need to follow in order to protect the personnel and equipment including busbars
c. where can I find installation details for busbars

I appreciate your inputs in advance
 
Electriman said:
Greetings,

I am working on a project where I need to run insulated copper busbars to feed the load. I know in the normal world, I can buy the busduct to for this purpose but due to the cost, I've decided to buy the individual insulated busbars to run to the load. Now I am facing a couple challenges:
a. What is the position of the NEC in busbar wiring
b. What are the minimum safety requirement that I need to follow in order to protect the personnel and equipment including busbars
c. where can I find installation details for busbars

I appreciate your inputs in advance
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There is only like two NEC sections that possibly apply

368 busways (which is basically your mentioned busduct)

370 cable bus - but that doesn't seem to be quite what you are wanting to do.

I don't think you can build your own for the most part, and if you can you probably have about as much into it as you would with busduct anyway. The real bus duct would likely be listed and such easing some the liability you may have if you made your own.

368.120 (in the construction requirements doesn't mention needing to be listed, does mention marking voltage and current rating and manufacturers name or trademark though.
 
Electriman said:
It is about 500 VDC and 5000 A.
Click to expand...

What's the usage and environment? That will direct some of the options.

FWIW, most heavy-rail transit systems, which are more like 650v-750v but still over 4000 amps usually use "wires" to connect the rectifiers to the track (where "wire" is on the order of 600-800kcmil, and you'll see 5-6 right next to each other). Can you do that instead of using bars? Eight strands each of 800kcmil type W/G/SC will get you there at 60deg (5440 amps, from 400.5(A)(2)); step up to 75deg and you can drop one or two leads.

Or give one of the wire manufacturers a call and see what they recommend.
 
It seems to me that an insulated bus bar is no different than any other insulated conductor and would need to be in some kind of raceway. I think by the time you made the bus bars and then put them is some kind of enclosure, you might well find it more cost effective to use bus duct or just regular conductors.

You could take a look at insulated flexible bus bars. There are a number of companies that make them.
 
petersonra said:
It seems to me that an insulated bus bar is no different than any other insulated conductor and would need to be in some kind of raceway. I think by the time you made the bus bars and then put them is some kind of enclosure, you might well find it more cost effective to use bus duct or just regular conductors.

You could take a look at insulated flexible bus bars. There are a number of companies that make them.
Click to expand...
Is that "cable bus" which is covered by art 370 or is it still a 368 wiring method?
 
kwired said:
Is that "cable bus" which is covered by art 370 or is it still a 368 wiring method?
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No. It is not a wiring method at all, just a conductor.

Here is one brand.


IIRC, it is recognized as AWM so can only be used in UL listed applications where it is accepted by UL such as UL508a, MCC's, panelboards, etc.

It sounds like the OP does not care if his application meets code or is UL listed anyway so not sure that crossing the i's and dotting the t's would matter much to him.
 
Busbar is tricky. Especially with the current you are talking about. Force is the big thing. So it’s an engineered system which is why NEC is silent. Otherwise you get about 1000 A per inch as a general rule of thumb so a 6” wide bus bar or a couple smaller ones will work. Cooling is another design issue.
 
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