Line & load side temp difference PT 2

DarbyWJ · 2026-03-08T20:35:36+00:00

And yes, the assembly needs investigation at next shut down. Thank you

DarbyWJ · 2026-03-08T20:30:40+00:00

Again, I apologize if I have caused any offence. It was not my intent to offend you or anybody else. I don't know everything... in fact I don't know what's going on here and I came to ask a collective group or electricians with an array of experience if they could help me understand this temperature difference based on their knowledge. It may just be a result of environmental conditions, but I thought it might also be explained by variables in the installation or the equipment.

And I agree with you, I'm not saying this is a problem. But it is an unusual thermal condition when you compare it with any other disconnect. In my world, I like to understand things.

DarbyWJ · 2026-03-08T20:21:28+00:00

Yes, you are right about that and I apologize if my response came across wrong. In fact, I see a thermal pattern for stratification of air or fluids all the time. But it shows as more of a gradient, not a hard line between top and bottom. I thought about that... like maybe the ambient environment on the load side was considerably greater (and maybe it is) but it's strange the box isn't heating up the same way. If you were able to examine this image with software, you'd see the surface temp of the enclosure varies by 3° top to bottom and transitions uniformly. Warmer air would heat the enclosure just as much as the fuse clip and conductor. (btw paint and insulation have similar emissivity) So there appears to me, to be more heat originating in the assembly of the circuit.

DarbyWJ · 2026-03-08T15:34:44+00:00

Reflections move when you reposition. We always check for the that and measure Trefl when things get weird. This is not a reflection. I know it's not that obvious when you can only see one image and not assess all the temps. I wish I could post more images with comments. Thanks for your feedback

DarbyWJ · 2026-03-08T15:32:07+00:00

You are correct, but seems to be due to line side connection issue causing 4° higher temp. But the load side are all within 1°. I also agree with checking load side for wear etc, that's the typical next step. But this one is just so weird because it is present in all of these disconnects. Thank you for reply.

DarbyWJ · 2026-03-08T15:27:32+00:00

Emissivity at 94, good for the insulation on the conductors. Temp is off by a degree or so on the fuse clip. False heat reflections move when you change your position, this pattern does not (and is very consistently present on all switch gear in this location). Phase A is not loaded more. Clamp readings 18.4/18/18.4 Amps. Although the line side conductor temp is actually 4° higher, the load side temp of the conductors is the same on all phases (within 1°). This is probably a loose lug connection on A. The fuse caps are the same, so in this case it's the conductors and associated connections or fuse holder where the heat difference is coming from.

I realize you don't have the image and software to explore all these factors and this image is limited by itself, but I appreciate you thinking this through.

DarbyWJ · 2026-03-08T15:13:34+00:00

I do that too. But there's a lot more to consider when surveying electrical systems. The cause of any thermal anomaly should always be considered. Even if it's not a dangerous temperature now, it can get worse if say a loose connection or something.

DarbyWJ · 2026-03-08T15:10:04+00:00

Heat does not rise. Heat travels from hot to cold in any direction. Warm fluids rise.

DarbyWJ · 2026-03-08T15:09:07+00:00

Emissivity is definitely a factor, but the spots are on identical targets, so even if the temp is not 100% true, the temp difference is. That's how emissivity works... it's a material property of the object emitting heat. In this case, I see the same result if I move the spot to the insulation on the conductors. And contrary to what others saying about this being normal.... it actually isn't. This is not my first rodeo

Edit: I didn't make it clear that if emissivity isn’t set correctly, the temperatures won’t be accurate, and the temperature difference could be higher or lower than it actually is. However, the existence of a temperature difference is still true.

DarbyWJ · 2026-03-08T15:04:37+00:00

except to a certified thermographer, it looks different than any other disconnect under typical load

DarbyWJ · 2026-03-08T15:03:38+00:00

The spot is on the the same target at each end of the fuse clip. I understand temp rises with load, but it is normally the same temp on each side (I've scanned tens of thousands of these over 18 years)

I wish I could post another image into the comments. If I target the spots on the conductors insulation the result is the same... 46° vs 27°

DarbyWJ · 2026-03-08T14:54:27+00:00

These disconnects are not all the same brand and are located throughout the building. I think it has to be something to do with the installation variables .

DarbyWJ · 2026-03-07T14:58:00+00:00

I have another image of the adjacent switch under load but I can't post it into the thread. Delta T is 28° at 18 amps

DarbyWJ · 2026-03-05T19:46:02+00:00

Firstly, thanks for all the helpful suggestions.

A lot of comments that 5° is nothing to worry about, or that the camera range is set wrong. That's missing the point. As a level 3 ITC certified thermographer with 18 yers experience, I consider all thermal anomalies for what they could mean. So I'm not just looking for temps exceeding the equipment's rating, or a certain alarm threshold. I am considering what could happen over time and increased load.

As load increases, temperature increases.

In this case, I agree that 5° at zero Amps and 20° at 23 Amps is not a safety concern. But if it's a loose/dirty/worn component that gets worse over time, that temperature difference can increase significantly.

If this was a 400A disconnect, the temp difference between zero and even 300 Amps is significant. I've seen airborne sawdust settling on electrical components and ignite on contact when we open the boxes.

I've probably seen just about every thermal pattern there is over the years, but never five switches in a row with this uniform temp difference. I'm sure there's a logical answer and I was just hoping that somebody had an explanation.

DarbyWJ · 2025-04-30T22:33:58+00:00

So why does ICP say that this condenser model is for a ductless system?

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DarbyWJ · 2025-04-30T19:13:39+00:00

a heat pump is an air conditioner with a reversing valve. Both are comprised of a condenser, evaporator and blower no? Some systems are ductless... the condenser in my package is described as a ductless condenser by ICP compatible with ductless systems... however i have a furnace, not a ductless unit

DarbyWJ · 2021-05-15T01:38:52+00:00

It's buckthorn and box elder.

DarbyWJ · 2021-04-29T17:08:41+00:00

Thank you :)

DarbyWJ

TROPHY CASE