I just have a couple of General questions. I am a knuckle-dragging cretin when it comes to my clamp meter. It has never stopped me from being electrocuted in the past.

I understand when it's on a single line and display 0.00 that there is no current. What does it mean if it displays 0.03 or 0.07?

When I hang it on a live wire it does not display any thing but 0.00. It is heavy romex. Do clamp meters have a problem penetrating the Romex covering?

Thank you in advance for any help you might provide.

 

I just have a couple of General questions. I am a knuckle-dragging cretin when it comes to my clamp meter. It has never stopped me from being electrocuted in the past.

I understand when it's on a single line and display 0.00 that there is no current. What does it mean if it displays 0.03 or 0.07?

A digital clamp meter measures AC or DC current. The value shown on the display depends on the particular device you are using, what function and what range you have it set to. Presumably the values you post are current in Amps.

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When I hang it on a live wire it does not display any thing but 0.00. It is heavy romex. Do clamp meters have a problem penetrating the Romex covering?
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Romex is a non-metallic sheathing so it will not interfere with clamp meter readings. The sheathing usually surrounds more than one conductor. To get a reading, you must clamp it round a single conductor. Then it will only give a reading if there is current flowing, and if the meter is switched to the correct AC or DC function, and a suitable range.
I hope this helps you to understand the use of your clamp-on ammeter.

 

Clamp meter?

Are you measuring current?
Below, left side will read 0 while the right side reads current. This may be the problem.

 

A digital clamp meter measures AC or DC current. The value shown on the display depends on the particular device you are using, what function and what range you have it set to. Presumably the values you post are current in Amps.

When I hang it on a live wire it does not display any thing but 0.00. It is heavy romex. Do clamp meters have a problem penetrating the Romex covering?
[/QUOTE]

Romex is a non-metallic sheathing so it will not interfere with clamp meter readings. The sheathing usually surrounds more than one conductor. To get a reading, you must clamp it round a single conductor. Then it will only give a reading if there is current flowing, and if the meter is switched to the correct AC or DC function, and a suitable range.
I hope this helps you to understand the use of your clamp-on ammeter.
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The clamp meter instructions tell me to use 20, 200 or 600 amp settings. If it's a dead wire it returns 0 no matter which of those settings I have it dialed to.

It's an older house with a mix of some really old electric lines with some new Romex lines. I want to eliminate the old lines to access some vent work. When I hang the meter on some lines they return nothing. When I hang it on the line a couple of inches away that is also an old mine it returns 03 which I was guessing might also have some residual electricity in the line?

I use the same process on the Romex lines. When I hang the meter close to a light bulb that is on (lit) it does not show that there is any electricity going to the light bulb. It reads 0.00?

 

When I hang it on a live wire it does not display any thing but 0.00. It is heavy romex. Do clamp meters have a problem penetrating the Romex covering?

Romex is a non-metallic sheathing so it will not interfere with clamp meter readings. The sheathing usually surrounds more than one conductor. To get a reading, you must clamp it round a single conductor. Then it will only give a reading if there is current flowing, and if the meter is switched to the correct AC or DC function, and a suitable range.
I hope this helps you to understand the use of your clamp-on ammeter.
[/QUOTE]
The clamp meter instructions tell me to use 20, 200 or 600 amp settings. If it's a dead wire it returns 0 no matter which of those settings I have it dialed to.

It's an older house with a mix of some really old electric lines with some new Romex lines. I want to eliminate the old lines to access some vent work. When I hang the meter on some lines they return nothing. When I hang it on the line a couple of inches away that is also an old mine it returns 03 which I was guessing might also have some residual electricity in the line?

I use the same process on the Romex lines. When I hang the meter close to a light bulb that is on (lit) it does not show that there is any electricity going to the light bulb. It reads 0.00?
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If it's a dead wire it returns 0 no matter which of those settings I have it dialed to.

"dead"? It reads 0 because there is no current in the wire. (no load) There may be voltage which is a live wire.

I use the same process on the Romex lines.

Back to post #2, left side. Romex has two/three wires in it. It will read 0 even then the light is on and there is current flowing. In the case of Romex you must septate the black and white wires and measure only one at a time.

 

Thank you for that. The easiest thing may be just to trace all the wires back to the breaker box I guess. Because it is an old house they have spliced wires and there's these old glass insulators and on and on.

 

Your meter can read voltage! Do you have the voltage probes?
Set the meter to AC volts and you will have to connect to copper.
See the probes at the bottom of this picture.

 

Yes I have the probes. The reason I got the meter was because I was working at a grain mill for a Grain Company in Slater, Wyoming and an electrician told me in order to check fuses I needed one. There were literally hundred if fuses in boxes that I had to work through. But that was a few years ago.

When I read the instructions I thought I just needed to hang it on the wire and see if electricity was passing through it by checking if the display wasn't zero (0).

 

hang it on the wire and see if electricity was passing through

Yes and no. If you hang the meter on a wire and turn on the light bulb you will see current flow. 100W old style bulb will draw just under 1 amp. The new LED bulbs will draw 0.1A more or less. If you turn off the light no current flows so the meter reads 0.

I have two different types of non-contact voltage tester pens. They only tell you if the voltage is above 50 volts. They cannot tell if it is 120 or 220 or 440. They do not work on DC. The one in the picture runs from about 10 to $49 depending where. Push the power button and get very close to the wire and a light comes on and it makes a sound. It only looks for AC voltage and does not know about current. This is probably what you should have used to test fuses.

 

Thank you for that. The easiest thing may be just to trace all the wires back to the breaker box I guess. Because it is an old house they have spliced wires and there's these old glass insulators and on and on.

That sounds as though the house needs to be completely re-wired to bring it up to safety specs. Only a qualified electrician can do that. You will never get home insurance if the insurance company is aware of the condition of the wiring.

 

Look at this picture. The current flows from the breaker box (source) to the light bulb and back to the breaker box through the other wire.

If you clamp the meter around both wires the meter measures the current going one way MINUS the current going the other way. That equals ZERO.

If you measure around ONE CONDUCTOR ONLY you get the current in the circuit.

You CANNOT just clamp the meter around the romex. It will always INCORRECTLY READ ZERO if you do.

 

Thank you.