Current leakage on residential service

[plate]

Karl:
I'd like to know about the zero button on your Extech, does it really zero in AC current or DC only?

The zero buttons are typically to zero for DC measurements.

per a fluke moderator: The zero input behavior of a true RMS multimeter is different from that of an averaging meter. With a true RMS meter you will never see 0 for the input measurement when readings are not being taken. The true RMS converters require a certain input level to make a measurement. So when nothing is being measured you will notice a deviation. The meter accuracy specifications still apply however and are not affected.

 

[don_resqcapt19]

Bill,

I've checked a few appliances but lets take one, a gas dryer. It has a three pronged power cord, so it has one path to ground. Another path that somebody pointed out above, the gas line itself. Where shall I start? I have a Fluke 1507 insulation tester, no megger.

I said that the gas dryer has another path in post #27. As I have said all along if there is another path you may have enough leakage current to read on your meter. I have also said that if there is no other path or if the other paths have a high enough impedance to limit the current to nanoamps you won't read it on your meter. You have been talking about isolated appliances without additional current paths. In that case the only leakage can be between the conductors of the supply cord and the currents will sum to zero.
Don

 

[wptski]

Brian:

I'm taking all the abuse, why did I get under your skin?

My question is in Post #100, to Don or anyone else.

 

[wptski]

plate:

Yes, I agree and that's why I asked about the zero button, never seen one function on AC.

Correct, I think that I mentioned above but you have explained it much better than I did!

 

[wptski]

Don:

Okay, the dryer test is out! Any other two wire power cord, I "think" has checked at .01ma or as low as this meter can go. Are we done yet? Maybe almost done!

 

[dereckbc]

Bil for any two wire appliance you should always net zero assuming there is no connection to ground like a TV where a CATV coax is involved. So you want to try something? Try something like a coffee pot, iron, or blow dryer with a large current draw.. If you clamp these itens around the power cord and read something, your meter is in error with no iffs, ands, or but's.

 

[don_resqcapt19]

Bill,

I "think" has checked at .01ma or as low as this meter can go. Are we done yet? Maybe almost done!

And since that meter has a plus or minus 5 count accuracy, that number doesn't mean anything.
Don

 

[wptski]

Bil for any two wire appliance you should always net zero assuming there is no connection to ground like a TV where a CATV coax is involved. So you want to try something? Try something like a coffee pot, iron, or blow dryer with a large current draw.. If you clamp these itens around the power cord and read something, your meter is in error with no iffs, ands, or but's.

Dereck:

My meter has a .01ma resolution, so it can't read zero. Okay, I used a 1875W hair dryer. Depending on the location of the cord in the jaws, it read from .07ma-.6ma. You and others will call that meter error but from what I gather reading/searching for several weeks is leakage! That's the disagreement here. I don't even think that if I found the documents to back me up by explaining it that anyone here would change their views.

Here's another thing. I clamped the AEMC 565 around the two 120V wires and the neutral at the POCO to my home, it read exactly the same as the AEMC F25. Is that meter error again? Of course, the 565 isn't in the ma range but it's higher amp range.

 

[wptski]

Bill,

And since that meter has a plus or minus 5 count accuracy, that number doesn't mean anything.
Don

Don:

Much better than the Extech 380947 mentioned above! By the way, what's in your toolbox?

 

[dereckbc]

My meter has a .01ma resolution, so it can't read zero. Okay, I used a 1875W hair dryer. Depending on the location of the cord in the jaws, it read from .07ma-.6ma. You and others will call that meter error but from what I gather reading/searching for several weeks is leakage

You are absolutely correct, no one will agree with you, especially a physicist by the name of Kirchhoff. Might try reading Kirchhoff?s law sometime. What you just described is impossible and violates all laws of physics. Basically says all current leaving the source must return to the source, not just sum of it, all of it so the net is always equal to 0, no more or no less to any degree.