In this video, Eric Mele shows how to use a 10-wrap wire rig to amplify low voltage and condensing fan signals for more accurate current measurements.
To make a 10-wrap rig, you simply take one strand of wire and wrap it to make 10 individual strands in a loop. You can put an ammeter clamp anywhere on it and get a more precise amperage measurement than your meter allows by using a little bit of math.
When you measure the amps on a rig with 10 wraps of a single wire, the amps of the wire itself are multiplied by 10. Thus, when you apply your ammeter clamp to the 10 wire rig, all you have to do is take the measurement and move the decimal point to the left to determine the amperage of a single wire. The 10-wrap rig also isolates the wire and makes you less likely to pick up amperage from other nearby wires.
For example, you could check the amperage on a condenser fan motor and yield 1.1 amps. When you use a 10-wrap rig, you will get a measurement like 11.8 for the wire with 10 loops. You move the decimal point over and get an amperage reading of 1.18 for a single wire. That's a lot closer to 1.2 than 1.1, and that extra precision can be quite helpful.
We use #14 wire with male and female spade connectors in this video.
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Hi this is eric with halo services and hvac school, and today i'm going to demonstrate how to create your own and use your own 10 wrap wire diagnostic tool. Now you may be wondering what is this tool and what is it for? It is simply a length of wire that we've wrapped around to make 10 individual strands at any point that i can put an amp clamp on this ring of wire so anywhere i counted on here, except for obviously the bottom, where they overlap is going to be 10 pieces of wire, i can put my clamp reader on anywhere around this circle. The way i've oriented this one and get the proper reading. So what this is useful for is, if we turn on this meter.

If you look at the amp display, it only displays in 10th of an amp increments, but there's 0.0 on this meter. It does not read to the hundredths place. So if you need to get a more accurate reading with this meter or a meter similar or even a meter that does count further, you can make this 10 wrap and then you simply move the decimal place to the left to get your actual reading. Now, what this also serves to do is to move your measuring point away from other wires see.

I can move this out of the unit away from other wires that might be interfering with my reading, so i'm going to demonstrate using it on an air handler low voltage circuit and also on a condenser fan motor, because that's what i have available to me to Demonstrate now some other uses of this could be to test small defrost heaters for refrigeration, anything where you need to critically measure low amperage. So i'm going to get this unit opened up and we'll hook this up show how to take a measurement with it. We have our 10 wrap plugged onto the transformer in the place of where this red wire would normally plug in and we have the red wire plugged back into our 10 wrap. So the most common connection i keep on this 10 wrap is a female spade.

Connector and a male spade connector, because that's the most common things i would use it for, and you can see on the meter here, we're drawing it says: 0.43 amps, even though the unit is idle. Now we would move that decimal point one place to the left and that would equal 0.43 amps right now. So if i went over here to we're actually drawing - and if you look at what the meter would normally say, it's saying from point three to point four, but on our ten rap we get a true reading of closer to what it actually is. So you could use that in your low voltage control circuit for diagnostics, pretty much anywhere, as i mentioned, that you need the resolution that your meter doesn't regularly provide right.

So let's take a close look at what this thing is. I know the first shot. Probably wasn't the best example. This is just one strand of wire one piece of wire.

I should say in this case i use number 14 wire and it's simply 10 loops anywhere. I'm going to put the meter so one two, three four, five, six, seven, eight, nine. Ten, and if i count over here, it's the same thing, one two, three four, five, six, seven, eight nine ten. The only discrepancy right here is where i purposefully put this cable tie, so that i remember not to put my meter past there and i have the wires tied together see here.
They overlap one more time right there at that point under that cable tie would be 11.. Keep that in mind when you're making one to just count the strands and make sure they're good, where you're going to measure. So in this case, i can measure anywhere around the circle, except for where i've purposefully blocked myself from being able to measure, and i make it long. I leave the ends.

This configuration the male and female spade because that's the most common, but if you leave it long, you can snip it a couple times. If you have to in order to get the ends, you need, but pretty much, that's the only ends i'm using. You could also make adapters that plug into this. If you don't want to keep cutting it, but that's pretty much that all right.

So now we have our wire wrap hooked up to a condenser fan motor. Now this is a ec motor, maybe not the best example, but you see we get 1.1 amps there and in the unit we might even get a little different because we're near other stuff we're getting depending on where we move it. Actually, this one's staying pretty stable when we go to our 10 wrap here, you see we get a reading of more like 1.18 1.19 because we're moving that decimal point one place to the left. You gain a bit of resolution.

By doing this, it's not always necessary for what you're doing, maybe not even for what i'm demonstrating it on, but i have to demonstrate it on something tool to have in the toolbox. Winning, if you need it thanks for watching our video, if you enjoyed it and got something out of it, if you wouldn't mind hitting the thumbs up button to like the video subscribe to the channel and click, the notifications bell to be notified when new videos come Out hvac school is far more than a youtube channel. You can find out more by going to hvacrschool.com, which is our website and hub for all of our content, including tech tips, videos, podcasts and so much more. You can also subscribe to the podcast on any podcast app of your choosing.

You can also join our facebook group if you want to weigh in on the conversation yourself thanks again for watching you.

16 thoughts on “How to easily measure low amperages in ac”
  1. Avataaar/Circle Created with python_avatars Apartment Maintenance says:

    Nice 👍

  2. Avataaar/Circle Created with python_avatars Dwayne Doxilly says:

    Cool you are awesome with this information

  3. Avataaar/Circle Created with python_avatars Donnie Robertson says:

    Nice job and video like always

  4. Avataaar/Circle Created with python_avatars Roman Adriel says:

    I use this trick for thermopiles when I'm too lazy to lazy to walk back to the truck and get the proper tool😬

  5. Avataaar/Circle Created with python_avatars Paul Rozinski says:

    If necessity is the “Mother of Invention” , DESPERATION is its father😂. Great job Eric, handy tool to have👍.

  6. Avataaar/Circle Created with python_avatars Lavar Berry says:

    or you can use a small amp Meter with 6A and 2A setting Are you in Orleans ?

  7. Avataaar/Circle Created with python_avatars Ben says:

    I do this in school

  8. Avataaar/Circle Created with python_avatars M.A. M.R. says:

    Cool but don't see how It would help since you can look at your meter funny and the amp draws could change.

  9. Avataaar/Circle Created with python_avatars Wiliam Bennett says:

    Thank you for this information. So what you've done is made an air coil that allows for the measure of the inductance. Like a choke on a radio antenna. Awesome 👍

  10. Avataaar/Circle Created with python_avatars noufal kilayil says:

    👍

  11. Avataaar/Circle Created with python_avatars Waylon Wells says:

    👍

  12. Avataaar/Circle Created with python_avatars Garry Graves says:

    Very creative idea for low amperage measurements 😊!

  13. Avataaar/Circle Created with python_avatars nota newbie says:

    Knew about this, but have never used it. THANKS ALOT!

  14. Avataaar/Circle Created with python_avatars AG says:

    Smart man 👍👌

  15. Avataaar/Circle Created with python_avatars Charles Perez says:

    very good information but the (10 wire wrap) is that Gauge Wire and inches center of wire wrap

  16. Avataaar/Circle Created with python_avatars Jeff B says:

    Good information Service area Kanata??

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