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Discussion Starter · #1 ·
Other daughter's house this time. I know this one can be a bit of feud starter and that is certainly not my intention. You guys are great so I just want your opinion/advice on this - thank you.

New 3 ton A/C condenser installed in 2017 - 30A max fuse/breaker on label; 40A 2-pole CB in panel; 8ga. wire; stab pull at disconnect box. Been that way for 2 years now w/o any issues.

Should I leave the 40A CB in the panel and replace the disconnect with a 30A fused one, or just replace the 40A CB in the panel with a 30A CB ?
 

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It'll be code legal if you change the breaker to a 30 amp. It won't be if you change the roof switch to a 30 amp fusible or leave it as is. It's not code compliant to feed a 30 amp switch with a 40 amp circuit so don't miss this good opportunity to correct that. Go with the the new 2pole30 bkr.

Nothing to debate there. :sad: We'll find something else. :biggrin2:
 

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A "Handy Husband"
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I would find other things to occupy my day and leave it be. The 40 amp breaker protects the #8 wire and there is no real danger.

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I get what y’all are saying about leaving the 40 amp breaker in. I see it quite a bit. My only issue would be if let’s say the capacitor went bad and the compressor was trying to start. It could trip that 30 amp pretty easily. But if the compressor kept trying to start with the 40 amp breaker it may keep trying to start until the compressor (winding issues) burns up. The capacitors burn up fairly frequently any more. In the same breath that unit could run 20 years with no issues with the 40 amp breaker just the way it is.
 

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A "Handy Husband"
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I would find other things to occupy my day and leave it be. The 40 amp breaker protects the #8 wire and there is no real danger.

Sent from my RCT6A03W13E using Tapatalk
Those who advise you to take a risk have nothing to lose. Blow them off and do the right thing.
Do you ever plug a 15 amp device into a 20 amp circuit? Better stop, it may be dangerous and your insurance company will not pay if you burn your house down(•‿•)

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The act you describe isn't an NEC code violation. His situation is. There are numerous reasons for the specification tag on the HVAC unit setting the maximum breaker size. They all are based on safety issues. That information is so important that without it the unit could not be sold.

I can only give the time of day as I see it. If you don't choose to set your clock, that's your choice, I have no quarrel with that. To each his own.
 

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Discussion Starter · #11 ·
Thanks so much so far everybody, I really appreciate it all.

I'm a bit surprised to tell you the truth that nobody wants me to just replace that disconnect with either 30A fuses or a 30A breaker = label requirements met and wire from panel protected. The whip is also 8ga.

I myself bought a nice new system last year and the pros who installed it all put in a nice shiny new 50A breaker disconnect. Oh, and yes, the CB in my panel is a 60A !
 

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The switch is only rated for 30 amps. It isn't fused. Buy and install a 30 amp switch that is fused and you still are not code compliant regardless of what size fuse you put in it. You still have a 30 amp switch on a 40 amp circuit. Buy a 60 amp switch and fuse it for 30 amps and you'll be code compliant but it will cost considerably more than changing that breaker and much more work.
 

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The switch is only rated for 30 amps.
I've re-read the thread a few times and still don't see where that was stated.

Buy and install a 30 amp switch that is fused and you still are not code compliant regardless of what size fuse you put in it. You still have a 30 amp switch on a 40 amp circuit.
Disconnects (and switches in general) need only be rated for the load they are actually disconnecting (or switching), not for the circuit. Does your home have 20A lighting circuits? Take a look at the switches. How many 20A switches do you find installed?

Furthermore, on specific purpose branch circuits like the one in question the circuit rating is not determined by the breaker size. So while it may have a 30A or 40A breaker installed it's not a 30A or 40A circuit.
 
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