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Old 07-08-2019, 09:45 PM   #21
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Quote:
Originally Posted by Bird dog View Post
Could you cite a code reference for that please?

MC has THWN-2 wire in it and it's rated for 75 deg
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Old 07-08-2019, 09:48 PM   #22
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With an MCA of 47A, #8 would be fine.
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Old 07-08-2019, 10:03 PM   #23
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330.80--->310.15

We use the 75 degree column for MC, same as THHN.

That would be getting #8 MC, not #6. This isn't 60 degree column Romex.
Are all the terminations rated for 75 degrees according to 110.14(C)(1)(a)?
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Old 07-08-2019, 10:54 PM   #24
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Are all the terminations rated for 75 degrees according to 110.14(C)(1)(a)?

You will find very little, if any, new equipment these days that isn't 75 deg. rated. Especially in HVAC stuff since NM is not the "go to" wiring outside of resi.
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Old 07-09-2019, 05:59 AM   #25
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The condenser is 1p. The air curtain is 3p. Come on
And both are supplied by ONE three phase circuit.
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Old 07-09-2019, 07:03 AM   #26
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My thoughts exactly. Are you adding a panel or are you trying to run this on one circuit. Best bet is to run 2 circuits unless the distance is far
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Old 07-09-2019, 08:08 AM   #27
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Condenser not on site, cooler company emailed spec says 4hp 1p 208v
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Old 07-09-2019, 08:20 AM   #28
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Some of these responses from you guys are really bizarre.
I gave the specs for both, if one was to combine them on one ckt which isnt wise or to code, it would need a 90 amp MCA. You cant have 2 circuits with combined RLA of approx 61 amps with max OCPD of 50 each on one circuit.
How was it not crystal clear i was buying the wire, not yet installing?
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Old 07-09-2019, 08:25 AM   #29
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Quote:
Originally Posted by Bird dog View Post
Quote:
Originally Posted by Cow View Post
330.80--->310.15

We use the 75 degree column for MC, same as THHN.

That would be getting #8 MC, not #6. This isn't 60 degree column Romex.
Are all the terminations rated for 75 degrees according to 110.14(C)(1)(a)?
I thought about this but couldn't be certain so im going with 6 awg
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Old 07-09-2019, 08:31 AM   #30
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Quote:
Originally Posted by WPNortheast View Post
Some of these responses from you guys are really bizarre.
I gave the specs for both, if one was to combine them on one ckt which isnt wise or to code, it would need a 90 amp MCA. You cant have 2 circuits with combined RLA of approx 61 amps with max OCPD of 50 each on one circuit.
How was it not crystal clear i was buying the wire, not yet installing?
Wierd
That is the nature of written communication, things can be misconstrued and details can be lost. You didn't say the condenser wasn't there yet. It was unclear to me whether the two units were separate or not, hence my question about the nameplate. I wasn't suggesting you run two large pieces of equipment from one circuit, I thought it was a single point connection to run both. Stranger things have happened.

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Old 07-09-2019, 09:14 AM   #31
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Quote:
Originally Posted by WPNortheast View Post
Some of these responses from you guys are really bizarre.
I gave the specs for both, if one was to combine them on one ckt which isnt wise or to code, it would need a 90 amp MCA. You cant have 2 circuits with combined RLA of approx 61 amps with max OCPD of 50 each on one circuit.
How was it not crystal clear i was buying the wire, not yet installing?
Wierd
From your first post it sounded to me and apparently others you were looking to run one mc cable for both units.
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Old 07-09-2019, 09:35 AM   #32
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Now im confused with all the responses. He gave a nameplate rating with a MCA and a max fuse size. The unit has a three phase heater and a single phase (two phases no neutral) blower motor fed from the same three phase. It’s a single nameplate for a single three phase feed.

When you do the math they took the heater kw divided by the voltage (208x1.73=360) and came out with 36 amps. They multiplied that by 125% and added the single phase fan. One feed.

As far as the terminations, I’m sure 75c is the way to go. But nowhere does it state that. Not even when you look up the model #. The lugs themselves might be 75c but I don’t think that alone tells you the equipment temperature rating. Just like if the lugs says 90c we no it’s not. A breaker that is 100% rated isn’t as soon as it is installed in a panel or enclosure. That’s why I’m always afraid to go with the 75c column under 100amps. But chances are it’s fine at 75c.
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Old 07-09-2019, 09:37 AM   #33
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It reads, at least to me, that you had a single piece of equipment that had a single phase motor and a 3 phase heater.

At any rate, if you want two #6 conductors and a ground inside of a manufactured metallic cable assembly, you may be waiting a while. Otherwise, 6-3 is growing from the trees and you might as well use it and get it over with and get paid.
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Old 07-09-2019, 10:18 AM   #34
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This thread is a dog chasing it’s tail. Two pieces of equipment, separate runs, one 3 phase and one single phase. You guys can fight over conductor size. I would have no choice but #6.
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Old 07-14-2019, 09:08 AM   #35
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it's #8 and one 3ph circuit. the heater is 36 amps x 1.25= 45 amps Manufacturer did the math

then the fan is 1.4 amps (x 1.25)tapped from the 3 phase circuit and you get MCA of 47 amps. They already did the continuous circuit calculation so you don't have to .
the unit's controls turns on the fan when needed
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