Maximum Breaker Size for Condenser Units

[adair]

Brian,

Maybe time to upgrade Adobe reader.

http://www.adobe.com/products/acrobat/readstep2.html

[hausdok]

Okay,

Go to "Resources" above, click on "Downloads", scroll all the way to the bottom to the last two documents and you've got them.

ONE TEAM - ONE FIGHT!!!

Mike

[Brian G]

I got the Trane specs today. There's nothing as strong as Erby's quote from the Goodman specs, but....

Section F. Electrical Connections

3. Power supply must agree with equipment nameplate.id="blue">

I'm guessing the rest of what I'd like to have is in the warranty info, so I'll take a shot at getting that before I fire back.

Funny thing...Trane wrote they weren't "in the process of sending installation specs to non-Trane dealers", but first line of text on this document says:

IMPORTANT - This document is customer property and is to remain with this unit.id="blue">

They don't give out documents (or downloads thereof) that are normally customer property? Odd.

Brian G.

Getting There

[Garcha]

Brian, The simple answer for a client or realtor to understand is that if the breaker is too big the wire becomes a heating strip in the event of a short or other malfunction. Combine wire size and breaker/fuse size to make very warm house or should I say BBQ. I hit this one time and the only thing I had to do to convince my client was to show them the 50 amp breaker for the Range cable and the 50 amp breaker for the condensor. If the right size breaker gives trouble trips, too bad, it's time to fix the system so that it operates properly.

Mike

[Jim Katen]

Originally posted by Garcha

Brian, The simple answer for a client or realtor to understand is that if the breaker is too big the wire becomes a heating strip in the event of a short or other malfunction. Combine wire size and breaker/fuse size to make very warm house or should I say BBQ. I hit this one time and the only thing I had to do to convince my client was to show them the 50 amp breaker for the Range cable and the 50 amp breaker for the condensor.

Mike,

For most circuits, that's true. And your object lesson is a great way of communicating that to customers. However, in the case of an AC compressor, it isn't accurate. With these circuits, the overcurrent protection comes from the thermal switch in the motor, not the fuses or breakers. They're only there to protect against faults. As Brian already pointed out, there isn't a whole heck of a lot of difference in fault protection between differently sized breakers.

We should certainly be recommending that fuses and/or breakers match the data plate requirements. But in this particular case, it has nothing to do with wires overheating. If a customer or realtor asked me why the fuse or breaker has to conform, I'd tell them, "Because the equipment's UL listing requires it." If they asked what Bad Thing would happen if they didn't conform, I'd bring up the AC equipment warranty issue.

- Jim Katen, Oregon