What Size Breaker Do I Need for this AC?

opeepingtomo

Thanks

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jbfan

Max 125 amps at 240, max 100 amps at 208.
Either fuses or hacr type breaker.

Looks like you can also bring in 2 circuits at 60 or 50 amps each.

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Stubbie

I am in agreement with JBfan however can you give a few more details ?

This looks like a used unit ?

Are you installing this to replace another unit ?

It does have the heating kit installed?

Is there any secondary ocpd at the unit?

I'm seeing a lot of wear in the left of the image you posted.

opeepingtomo

Moved in recently and noticed it wouldn't heat.

Had guy from work who works on AC for living take a look and only one of 3 heating elements were wired up.

He wired them up and tested the heat and I let it run for a while. After I turned heat off the breaker tripped either while turning off or when I tried to turn on later.

I had him take a look again and he said the unit was pulling 65 amps when the heater turns on.
I currently have a 60 amp breaker for the unit.

Should I put in a 70 amp breaker or is something not right here?

Stubbie

If he wired all heating elements up to one circuit things changed drastically considering amperage draw. The MCA for one circuit is 91.5 amps and should be on a 100 amp breaker. If things were originally wired to operate on 60 amp breaker and only one heating element you now likely have too small of wire and too small of breaker.

It would be nice to now why the unit was installed at 60 amps. Maybe your service to the home is 100 amps?

kbsparky

It's possible that this unit was wired with a single supply line (#6?) connected to one breaker. If each of those elements is 5kW (and I suspect that they are), then you could possibly connect 2 of them to a single 60 Amp supply using a #6 wire.

Otherwise, you will need to ensure that the wire is sufficiently large enough to handle the combined load of all 3 elements using a larger breaker.

And ensure that your service is large enough to handle the combined load.

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opeepingtomo

Right now the house only has 100 amp service.

The unit does have #6 ran to it. The wire is a pretty short run too.

Speedy Petey

You need a service upgrade to 150 or 200A and a new circuit run to the heater.
Like the others have said, you either need TWO circuits of 60 amps, or one circuit of 125A.

Someone hacked this unit into this situation.

How big is the house?
What is the BTU rating of the unit?

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Speedy Petey

That unit is an 84 amp draw at full load.
I don't see anything that shows individual heat strips wired. Maybe it's in the instructions, but I doubt it. It should be wired all or nothing.

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Sometimes I feel like if I answer any more questions it is like someone trying to climb over a fence to jump off a bridge and me giving them a boost.