Bought a clamp meter, question.

[John Connor]

My new clamp meter a Uni-T https://www.amazon.com/dp/B00O1Q2HOQ/ref=cm_sw_su_dp just arrived.

Now I somehow thought that I could just clamp around an appliance and measure it's AC current. Not getting a reading and reading the instructions the diagram shows you use only one wire in the clamp.

My question: Is there a type of patch cord that separates the hot and neutral lines so that I can use my clamp meter on the hot or neutral and measure current consumption in an appliance?

My idea looks like this.

 

[pcgeek11]

You could make one using three wires ( Hot Neutral and Ground ) and connect a male plug on one end and a female receptacle on the other end.

The reason you don't get a reading is the current through both wires are cancelling out the induction into the coil of the clamp meter.

 

[John Connor]

Yeah, I thought about making one, but figured they would have something like this already. I just don't know what it would be called.

 

[Red Squirrel]

I just ended up making my own:



They do make solid plastic ones you can buy but they look kinda bulky and would be hard to use in tight spaces.

 

[pcgeek11]

:thumbsup:

 

[John Connor]

Well, I put a crappy little thing together. I'm going to make something better latter on, but so far this is pretty cool! First time I ever measured current actually. I mean I have mostly measured voltage, resistance, farads, and continuity.

So I measured my computer and was very surprised it only pulled around .800 mA - 1.0 Amps and spiked to 1.5 Amps when I launched Battlefield 2. So were looking at around 96 watts just on idle and spiking to 180 watts playing a game. The Antec 520 Gamer 80+ Bronze is pretty damn good. I heard those bronze, silver and gold labels were a poor indicator on PSU efficiency though.

My laptop is the equivalent to a 60 watt light bulb at idle and in fact the small fan on the patio pulls in more amps at around 70 watts.

I really like this purchase. It's pretty damn accurate from my testing and the reviews and a forum I read about this particular meter. The only thing I don't like about this meter is the light doesn't stay on longer or just doesn't stays on and the probe heads are too short to jam into an electrical outlet if I needed to. I have to see if my other probes will fit in this meter.

Another question:

What is this number 6.242×1018? Like Exa something? Would that be right?

 

[John Connor]

They do make solid plastic ones you can buy but they look kinda bulky and would be hard to use in tight spaces.

Can you post a link to one of these?

 

[Red Squirrel]

Here's one I just found:

https://www.amazon.ca/Extech-480172...W/ref=sr_1_11?ie=UTF8&qid=1471466537&sr=8-11&

 

[John Connor]

Ohhhh. I've seen those before. Never quite knew what they were. Thanks. I may end up buying one of these. I do like your setup though.

I see there is a 1x and a 10x. Do you know what that's for?

 

[Red Squirrel]

Hmm never noticed that. My guess is the 10x has the wire going 10x around so when you clamp it you are getting 10x the "energy" so the value will be higher. Would make it so you get a more accurate reading for low amp loads. You'd then divide the value by 10 for the actual amperage. I may be wrong though, I'm just guessing.

 

[John Connor]

That did occur to me. I should ask on Amazon I guess.

 

[Sheep221]

Clamp meter is intended to be used as an on-site diagnostic tool, it is mainly attached to wires inside distribution panels, infrastructure installations or heavy machinery. That's why if you want to measure load current of your appliances you have to make yourself a power strip where cord wires are separated from cable insulation tubing. You can't buy any adapter that would just leave out live wire for a clamp meter.
In this sense it would be easier to just buy residential power meter which does read load power, current and voltage and has receptacle and socket already built-in.
You can measure AC current with lead meter as well, you just have to again make something, this time additional terminals on measured wire.

 

[Red Squirrel]

Some can also do DC, which is nice when working with battery banks and such.

 

[John Connor]

This meter does DC as well.

Edit- DC amps that is.

 

[John Connor]

Just searched ebay for AC line splitter and I see the cheapest at around $10. I think for that price I'm going to go to Home Depot and buy the parts to make a better one. Especially when I seen a comment on a Crafstman that read something like he had to hold the AC line splitter to check the current at the same time. Which leads me to believe these AC line splitters are heavy while plugged into the wall.

 

[John Connor]

Finally made a more professional AC line splitter.

 

[Red Squirrel]

I would have kept a bit of the jacket sticking out, as the plug clamp will have something thicker to grab on. Less chance of getting a wire loose inside over time.

But it's nice and long so easier to clamp to. I made mine a bit too small.

 

[John Connor]

I just used regular wire. There is no jacket. I did tighten down the screws everywhere.

 

[agent00f]

Yeah, I thought about making one, but figured they would have something like this already. I just don't know what it would be called.

It's called a Kill-A-Watt and works quite a bit better, though technically those use a shunt resistor to measure current. For a cheap alternative you can just cut open whatever power cord, or even better if it's one of these just rip the two wires apart:

 

[John Connor]

Already made one...


An I would argue a real DMM would be a lot better than a Kill-A-Watt meter. Plus, the DMM is more versatile.

 

[Mr Evil]

...An I would argue a real DMM would be a lot better than a Kill-A-Watt meter. Plus, the DMM is more versatile.

Depends what you're trying to do. If you're just measuring current then a multimeter is probably more accurate, but if you want to measure power then a multimeter is inappropriate because it can't measure power factor.

 

[Red Squirrel]

From what I read the Killawatt is not very accurate. I've never tested one myself though. For power factor you just want to make sure you have a true RMS meter.

 

[Mr Evil]

...For power factor you just want to make sure you have a true RMS meter.

For power factor, you need to measure the angle between the voltage and current. You can't do that with a multimeter.

 

[Red Squirrel]

For power factor, you need to measure the angle between the voltage and current. You can't do that with a multimeter.

Isin't that what a true RMS meter does though? I thought that was the whole idea of getting one, so that the amp reading you get is corrected for the power factor.

 

[John Connor]

Yeah, and my meter is true RMS.