How would this wiring senerio be handled?

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Old 07-18-11, 08:45 PM
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How would this wiring senerio be handled?

Suppose for some reason, you had to run large conductors through large diameter conduit. And, this conduit was too large to fit into the main panel. Could that large conduit be run to a large enough junction box? Than, run two smaller or maybe run individual conduit for each conductor, to the main panel?
 
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Old 07-18-11, 09:24 PM
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Tell us the details. Commercial or residential? What exactly are you trying to do?
 
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Old 07-18-11, 09:43 PM
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Originally Posted by Nilzlofgren View Post
Suppose for some reason, you had to run large conductors through large diameter conduit. And, this conduit was too large to fit into the main panel. Could that large conduit be run to a large enough junction box? Than, run two smaller or maybe run individual conduit for each conductor, to the main panel?

Give us more detals what you try to attempt on this one and also there is one MAJOR golden rules with conduits DO NOT EVER run indivual conductor for each conduit this is a major NO-NO with steel conduit it can get them really hot and there are few doucment case they did catch on fire from that.


If this is a commercal location this have to be done by licesend …lectricien { correct spelling in French }

And also try to post the photo if you can so we can able assit you on this one.

Merci,
Marc
 
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Old 07-19-11, 07:04 AM
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Along with the other points already raised, in order to parallel conductors under the NEC they must be 1/0 or larger.
 
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Old 07-19-11, 10:19 AM
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What is the difference in size? Something like 3" could reasonably hooked up with a reducing bushing to 2.5", but if you're going 4" to 1.5" or something like that you'll need a gutter or pull box. With large conduits you also need to consider bending radius for the conductors with the size of the junction box.
 
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Old 07-19-11, 10:37 AM
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Why not just make your own knockout?
 
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Old 07-19-11, 05:33 PM
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How large are the conductors? How large is the conduit? Panelboard cans are typically 5 1/2" Deep, are you dealing with a panelboard or loadcenter?
 
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Old 07-19-11, 06:43 PM
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To be honest, I'm probably putting the cart before the horse here. Next year, we will build our new house. We will also build a pole barn. The distance between the panel in the house, and the panel in the barn, will be +/- 400 feet. According to a voltage drop calc, to keep voltage drop under 3%, for 240 VAC @ 100 AMPS, I would need 250 kcmil, in aluminum. I'm thinking aluminum because of the price difference. According to the Carlon website, I could pull up to 4 250 kcmil conductors through a 2.5" rigid pvc conduit. I would go a little larger though for wiggle room. So, my main thought was whether or not I could fit 3 or 4" conduit into the panel. Also, the pole barn will be designed to accept solar panels in the future. If that happens, wouldn't I need to supply the house with about 200 amps? Which, would require larger conductors and conduit.
 
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Old 07-19-11, 09:20 PM
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At four hundred feet I would be thinking about something different than feeding the barn from the house. Having the utility bring service to a pole about halfway between the two structures may be something to investigate. The pole would have the meter and a service panel and then feeders to the house and barn.

If that isn't practical then I would seriously look at getting a pair of transformers and boosting the voltage to 480 for the run to the barn and then dropping it again. Doubling the voltage halves the current and reduces the voltage drop to one-fourth. For 100 ampere/240 volt service to the barn (24kW) you would only have to use wire sufficient to carry 50 amperes plus voltage drop. The cost savings on wire would go a long way to paying for the transformers.

Also, you would likely NOT need the same size of equipment grounding conductor as the current carrying conductors. Normally for a maximum of 100 amperes a #8 copper or #6 aluminum conductor is sufficient but when the current carrying conductors are upsized for voltage drop consideration the equipment grounding conductor must also be upsized proportionally.

Last point, do you REALLY need 100 amperes with a maximum of 3% voltage drop?

And on the solar...24 kilowatts of solar panels is probably gonna cost upwards of forty grand, not counting any possible governmental assistance.
 
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