10hp 230v single phase compressor wiring help

[thinktwicez71]

youre reading the wrong column

90*c is for derating only.



90a is not excessive.

NEC code allows upto 250% of NEC FLC table current for inverse time breakers.

50*2.5= 125a.

The 70a or 80a may trip but try it and see.

This is because motors have whats called in rush current that can be 4-8x FLA for fractions of a second.



Make sure you use #6 THWN.

#6 NM-b is too small.



A bigger question is whether your PoCo will allow a 10HP motor.

Most have limits on HP.

What size service do you have?

Are you the only one on the transformer?

Are you at the end of the line?

A 10HP may cause considerable voltage sag on the service. If youre on a shared transformer, you may cause issues for your neighbors as well..

What's the difference between thhn and the thwn you recommended? Can they both carry the same amperage just one waterproof ?

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[thinktwicez71]

I would use this

http://www.homedepot.com/p/Steel-Ci...ed-to-14-Solid-Wire-2-Pack-L70-B2-5/100141680

Google "Home Depot Copper Mechanical Lug"

Thank you, that's what I had in mind


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[matt_i]

What's the difference between thhn and the thwn you recommended? Can they both carry the same amperage just one waterproof ?

Most THHN is also rated for THWN. I have around 15 assorted spools that are 8-15 years old and went to see if I could find one that was not rated for the "W" and I could only find one roll in 14ga blue with white tracer that was only MTW. All of the other THHNs are THWN per label or per printing on the jacket. I looked at SouthWire and all of their THHN is also rated for THWN-2 (which as I understand it means 90C rated wet or dry)

Its some pretty bad *** wire, being gasoline, oil, solvent, water and sunlight resistant. I've been using it to build tractor wire harnesses. I do know the jacket will take a lot more heat when heat-shrinking with a heat gun than the standard automotive wiring.

 

[wyliesdiesels]

What's the difference between thhn and the thwn you recommended? Can they both carry the same amperage just one waterproof ?

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The only difference is the wet rating.

However, as said above, most THHN is dual rated ThWN.

I use to say THHN then got corrected one day so now I just say THWN.

Now that backfired on me

I suppose i should say THHN/THWN to curtail any confusion.

 

[thinktwicez71]

Both the black 6 guage are this as well , so I'm all good , thanks

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