Cause-aluminum wiring or other?

While farting around in my garage today I decided to take off my panel and shoot it with my infrared to see if I could get any decent pictures. I noticed that I have one breaker thats hotter than the rest and that I have 2 strands of aluminum ground and the rest of the house is copper. Im pretty certain the aluminum is going to the a/c breaker which is whats hot in the picture. So my question is it common for aluminum to run hotter from the nature of the material vs copper or do you think its another issue I need to address?


Not at all!
Your question can not be answered with the limited info you posted.
Wrap an amp meter around it and see what it says.
All IR has to be backup .

Here’s your answer… the AC is ON so you are seeing the breaker that’s in use. Turn on another appliance and see that breaker get warm too! Imagine, a breaker that warms up when in use. Go figure!

The top breakers are the dryer(which I had running) and the water heater.

I was more curious if aluminum wiring would tend to run hotter than copper, the temperature reading wasn’t really high enough for me to be real concerned about a big issue.

But here’s what I was “farting around” with in my garage. I am insulating my west facing garage door since it gets hot as can be in the summer time in there.

Yes. Aluminum alloy is less conductive than copper so at a given gauge and a given amperage it will have greater resistance (hence greater heat production) than the equivalent copper conductor. Of course, you don’t typically use the same gauge aluminium conductor as you would a copper conductor for the same circuit, due to differences in ampacity.

How does that help you assess what you observed in your thermogram?

What was the load on that 45 amp rated breaker (both poles)? What was the size of the conductor? Was the temperature uniform throughout the entire visible length of the conductor? What was the max breaker and minimum ampacity specified on the condenser label?

Since it’s your house (the perfect learning ground), if you don’t know these things go back and check when you have the opportunity. They will matter to you in assessing what you see. Then we can decide if you 1. have an exception and 2. how significant or urgent it is.

I keep hoping Howard will fill us in on what he learned, good teachable questions Chuck

I know, I’ve been slacking on the follow up to Chucks excellent response. I’ve been car shopping with the wife and that’s taken up most of my free time at nights. I will post my findings hopefully tomorrow

No rush. We can do this whenever.

I would be curious as to how old his condenser unit was.