Clamp meter for main service

just wondering if it is worth buying a clamp meter? Instead of trying to figure out the main amp supply by the wire size, does anyone just use the clamp over the service feeds?
(I know there are other things to consider in figuring the supply amperage), but does anyone use one for that?
What other items would a home inspector use one for specifically?

I have a clamp meter but that is not what it is used for. I actually don’t see how a current reading can tell you anything that you would need to know in a standard inspection regarding the incoming service.


The amp meter will tell you the load presently on the wire you clamp it on and not the main amp supply. I use it sometimes to determine if the elements are good on an electric furnace but that is going beyond a home inspection.

Daniel, for our purposes, the main amperage is determined, typically, by the SEC size, Main Panel Board size and Service Disconnect size.

It would help you to learn the wire sizes.

Best inspecting to you. :smile:

A clamp meter will tell you actual current load, but not capacity, so it would not be of value for the purpose you describe. I carried a high end RMS Fluke clamp meter and used it as part of my thermography inspections to diagnose thermal exceptions in electrical equipment (this is Level-II/III Thermography stuff and well outside the standard SOPs for home inspection). I treated it as a separate service and charged separately for it but performed it concurrently with the home inspection and included it in the same report.

ok, that makes more sense, load, not capacity.
I know the wire sizes, and capacities, just thought that might make it quicker to determine service supply…
thanks everyone!

Chuck, since we are on the topic, I am trying to decide on an infrared camera right now, as I want to add it to my inspections. What model did you use? I am thinking either the Flir E4 or E5.
I didn’t really want to spend more than that right now, but maybe later if I get more into it.
FLir has one that is only $400, but the resolution is only 60x90. the E5 is 90x120.

I’m not Chuck, Daniel, but I advise getting least a Level I before your purchase. That way you will have a better idea of what to buy and what/how it can help you (with).

Some classes have imagers that you can try out there.

thanks, Larry,
I did take the cert course with InterNACHI, but realize that’s probably not the same as a level 1?

My imagers were all in the 15-25k range when new. I started with a FLIR EX320 in 2008 and upgraded to a T400 High temp range after. I personally wouldn’t even consider trying to use a 9hz imager. That would put you in the Exx class.

My best advice is to invest in training first, equipment second. The imager is not all you need to do thermography. You will need support /ancillary equiment also, depending on what thermography services you get involved in.

Not as part of a home inspection.

However if you want one here is what I have.


A clamp on ammeter will not tell you anything other than the current draw at the time you are checking it. It is of no benefit with respect to the service size. Service sizes are determined by doing demand load, not actual load, calculations. Doing load calculations is outside your scope.

If you are doing a Four Point inspection you are required to give an opinion about the adequacy of the electrical service size. Keep in mind that you are only giving an opinion. You aren’t doing load calculations.

If you want to know what the service size ought to be, you can download my free Residential Electrical Service Size calculator. It will help you determine the service size needed, the service conductor size, and conduit sizes.

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Are you a vendor, Michael?

No. I just thought it would be nice to include a price for him rather than a picture of mine. Plus it was easier.

Thank you…

Yes I got it