Undersized conductors for condenser?

Just wanting to double check my thinking that these conductors are undersized for the circuit. (Pics & observation below)

Observed 10 awg conductors feeding the A/C condenser. I could not view the jacket at the service equipment or the disconnected to verify type or temp. rating but the small bit I could see appeared to be type NM-B.
The condenser ampacity was 32.8 amps.


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Further info-
From the best I could tell, the cable appeared to be Romex brand by Southwire. If so, that would limit the rating to 60°C, thus 30 amps, correct?

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Correct. NM cable ampacity is according to the 60° C ampacity of #10 AWG which is 30 amps. From a code perspective the conductors are too small with a MCA of 32.8. From a practical perspective there will likely never be an issue.


50 Amp requires, #6AWG copper circuit conductor. #4AWG aluminum.

To myself, the conductor terminating at both the 50Amp and 30Amp disconnect look the same in AWG.

There appears to be 3 appliance disconnects. 60Amp, 50Amp and 30Amp.
Questions. #1: How did you realize the 50Amp disconnect is used for the HVAC condenser.
Personally, I am use to seeing a separate 60Amp disconnect close to the cabinet.
#2: How did you measure the circuit conductor AWG? I use AWG feeler gauges.

The OCPD does not have to match the conductor size for this AC unit. The minimum conductor size is 32.8 so #8 NM cable would be required with the 50 amp circuit breaker. To make it even more cconfusing if the wiring method were MC cable or conduit and wire #10 AWG could be used.


I understand Robert. Good point.

What is confusing me at the moment is that the circuit run appears to be entering the home. If that is the case, the circuit would be for the evaporator and not for the compressor/condenser.
The 60Amp conductors look like they could be used for the AC condenser unit.

Brandon what type of HVAC? AHU, Furnace and AC, Boiler and AC?

I try to not to read too much into what Brandon stated. He said that this is feeding the AC unit and provided a photo of the nameplate. Given its orange insulation Brandon is correct that it is #10 AWG. It is possible that the NM cable runs through the house to an external location elsewhere.

Again, I concur.
Because the NM cable runs, or appears to run into the house, I had to ask. I rarely come across exterior service panels.

Thanks, Robert. I reported the deficiency as observed & verbally told my client that it would likely not be an issue in real world practice. This is new construction so they can ask to have it corrected or as I pointed out, use it as leverage to get something else out of the builder.

Yes it should be corrected regardless of whether or not it’s a hazard otherwise this issue could be revisited when the buyer sells the home.

I think you are reading too far into things, Robert Y. There are only two (2) circuits within 10awg in this home. The Dryer circuit was confirmed testing the GFCI & ensuring the receptacle was powered off. That only leaves the AC circuit where the conductors at the disconnect were also 10awg & were still live.

Yes, new construction here will have the condenser cable enter the exterior wall, cross the attic to the rear exterior wall & come out into a disconnect box. From there, conduit feeds the condenser.


Agreed, I told them the ramifications could be having to correct it themselves when selling, future potential insurance claim denied for improper installation, condenser warranty voided, etc.
They told me they would probably still buy the house even if the builder didn’t fix it. That is when I told them to at least use it as leverage to get something simple such as gutters.

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So basically, you wrote, “Here is a defect,”. Turned to the client, winked, and said, “Not really”.

And is this ok? What other issues have a wink and a nod?

Odd. I would rethink this whole approach.


Interesting point. Since this is a known defect it should be corrected if not by the builder then it should be corrected by the buyer if they’re willing to ignore it for the sake of the sale.

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Nope, not at all how the conversation went.

Seems you reconsidered.

That is where our job ends, though it is important to include some potential ramifications if the defect is not corrected.


Brian, I have paused my current inspection to address your comments as they have unnerved me enough to lose my focus.

[quote=“Brian Cawhern, CMI, post:13, topic:235614, username:bcawhern1”]

I understand that there is a lot of the conversation between my client & I that is left out and replaced with “and”. This can allow much assumption & interpretation.

Your comments here are presumptuous, inaccurate and accusatory. I feel you were short-sighted in posting them & quite frankly, feel they are defamatory toward my character & ethics as both an inspector & a person.

I do respect you & your contributions to this board & our industry so even though I am not much for explaining myself to others, I would like to offer you the full context of the conversation that occurred with my client regarding this subject.

I reported/explained the issue to my client along with my recommendation for correction. My client claimed to be an HVAC tech (3 years) & said that it was unlikely for that unit to ever draw more than 30 amps, then asked me if I agreed. My response was “I do not know what amperage it might pull in the future but true that it would likely not be a problem regarding amperage”. I did encourage them to have it corrected so they would not have to contend with this improper installation when they went to sell, make an insurance or warranty claim.
The wife then told me that if her husband doesn’t think it is a big deal then they probably won’t even bring it up to the builder as they do not want to loose the house by pushing the builder. I respond that that is their prerogative but still recommend asking for it to be fixed. I lastly followed with “The builder doesn’t know that you do not care if it gets corrected or not, so ask them to correct it & if they say “No”, then negotiate for the builder to do something else that you would prefer instead” (leverage).


Deflamatory? Ok. I am just reacting to the information provided.

Others will also look to you for insight. Any other inspector reading this would have come to the same conclusion and may even consider it a good practice.

I will continue to warn inspectors not to call something out in the report and then go behind it and verbally minimize it to the point it is not a defect. Certainly not to provide leverage for the client to negotiate. The converse is also true. Do not write a soft report and verbally add teeth to the narrative.

I am glad you were able to add context. It should be helpful.


It would be best to forego this site if you are only looking for positive feedback. Don’t play the victim when you are called out for what you write.