Fellow inspectors! I’m confused on the matter of a 40a breaker used for max 30a AC Unit. Furthermore, I was unable to identify the aluminum wire size. I ordered wire gauges but they haven’t arrived yet. Could you please help. Thanks.
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There’s nothing to be confused about. It’s the wrong size circuit breaker.
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And it looks like it may be at least #10 AL. If so, it appears to be correct. 18.1 amps needs #12 CU. So, bump it up one for AL and #10 AL would work.
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Reason why I said I’m confused is because of researching blogs stating that as long service disconnect is present, which it is, service disconnect could prevent breaker from tripping.
It’s not supposed to be #6 or #8 AL?
Do you know what size AL wire is needed for 18.1 amps?
Cerrowire_Ampacity_Chart_210405.pdf (277.5 KB)
Is that what your training taught you? This is a fine example of blog bs.
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A fused disconnect could protect the equipment, but it’s rare to find those. Most installers use the $15 home depot cheapo disconnect instead of the $40 fused one.
I agree, but we are not talking about a fused disconnect. We are talking about the appliance disconnect that does not have a built-in fuse and has a circuit breaker upstream.
Are you saying you see in your area fused disconnects along with circuit breakers?
Yes, I have seen the fused ones. Functionally they look pretty much the same, they just have the fuses in the plastic pull out. They connect to a breaker in the main panel.
Older homes, not built by The Villages. “Old Florida” has some pretty wonky stuff. Maybe they down sized the AC? Maybe additional lightning protection? Maybe what the guy had on his truck? I dunno. I don’t like inspecting those houses anyway, they’re pure dog shite.
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What they might mean is that the service disconnect could be fused smaller than the breaker. Not all disconnects are fused though. Check to see if you have a fused disconnect or one with no fuses. If it is a fused disconnect, check the fuse size. If they have 30 amp fuses in there, they will pop before the breaker does, thereby preventing the breaker from tripping.
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To help with the confusion the equipment data plate requires either a 30 amp fuse or a 30 amp circuit breaker. Both methods would be acceptable. A 40 amp circuit breaker is the wrong size circuit breaker.
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Thanks for the feedbacks! You all have helped me out.
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We are not looking at an equipment breaker. That breaker is outside at the meter.
That breaker is sized for the wire down stream, not the HVAC sticker, which is sized for the equipment downstream. There is no discussion of the total configuration. One size may not fit all. You must inspect it all to make a call.
Show the disconnect at the equipment or inside the equipment.
There can be more than one load downstream of the disconnect. ie. Heat Pumps come with resistance heat of various sizes (or none), That is to be determined at install.
New equipment now frequently have breakers/fuses inside the equipment, which is what the sticker is about. Changing those are what the sticker is talking about.
Note: fuses must be a slow blow fuse type, not what they have at the corner store. The breaker must be HVAC type also, but almost all are that type these days.
There is an assortment of connect options from unit to unit. You must assess what is there, to determine what is OK.
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