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#213825 08/02/14 10:48 AM
Joined: Jul 2004
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G
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An interesting issue came up over on one of the Usenet groups

There is a Sea Breeze mini split air conditioner that has an installation manual that says it should be connected with 6 gauge copper. The label says "minimum circuit ampacity" is 26 amps. So who do you believe?
The breaker size is 50a.
http://www.irproducts.biz/documents/SB-NewMultiZone.pdf


Greg Fretwell
Joined: Apr 2002
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Greg:
Well, in the real world....the nameplate wins. I would rarely see an install manual; I would ask for it if I had a question, and hope the HO had it.

They may have sized the branch circuit based on the OCP?



John
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Quote
They may have sized the branch circuit based on the OCP?



Clearly that is what happened. ... in the 60c column


Greg Fretwell
Joined: Oct 2000
Posts: 2,722
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Curiosity query...

What was the Intensity level of Flames emitted (by the Usenet Members), when the reply Message stating:
"#10 THW Cu. is Adequate and Compliant"
was posted to the Thread???
laugh yay rolleyes bash

--Scott (EE)


Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!
Joined: Jul 2004
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One guy in particular still will not let it go.

They are off on a "continuous load" side track now.
I tried to explain that motor circuits already have the 125% of FLA requirement and this would be part of the minimum ampacity calculation.

I explained I would trust the engineer who did that calculation more than a tech writer who might not have English as his first language.


Greg Fretwell
Joined: Feb 2006
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Label for outdoor unit only... all the inside coils grab power from the outdoor unit.

Now why its ok to use 14/3 or4 between inside and outside can start another argument smile

Joined: Apr 2002
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Correct me if this is wrong....
The inside unit (fan coil) is fed from the outside unit (condenser) and there is factory OCP for the fan coil feed within the condenser.

Most of the units I have seen have 'factory' wiring from the Cu to the FC.



John
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I have 2 of these mini splits and one the inside units runs on low voltage that could be run with bell wire Spec'ed as thermostat cable. It is a very small load (a little fan and an electronic board).
The other uses line voltage but just at a few amps.


Greg Fretwell
Joined: Feb 2006
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A few amps x 4-5 inside line voltage coils adds up Read the specs 3.5x up to 5 so about 17 amps total inside plus 26 out 50 amps seems right


Joined: Jul 2004
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G
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The conductors going to each inside unit only carry the current to that unit. That is why they can be #14.
As for the outside unit, that is specified on the label and you have to trust the engineer who computed it.


Greg Fretwell

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