Earth Leakage clamp meters

[Jimmy Boy]

I want to invest in one of these, it's primary function will be for me to measure the mA on circuits where IT is in use, it seems they can be useful to determine where a fault might be on a circuit, I would be greatful for you opinions on these options.What i can't quite fathom and hoping someone can shed light on is the ranges, I want to read right down from say 1 mA - 30 mA, there is also a huge price difference on these products.

ATB J

TM-EL9809 High Resolution AC Earth Leakage Clamp Meter

Metrel MD 9270 Earth leakage clamp with Power functions

 

[snowhead]

The meter I used to have with a previous employer and all the meters I've looked at trying to get my current? employer to buy, were in the £300 to £400 range.

The resolution on the second link is only 10ma, you won't read 1ma.

More like this is what you need;

Kewtech KEW 2434 Earth Leakage Clamp Meter

 

[topquark]

Short answer: Both would be fine Jimmy.

Note that neither do DC though (which may not matter unless you're into Solar/car electrics). Also the max voltage on the TM is 400V (may be an issue).

The reason for the price difference (£100) is the Metrel is a TRMS meter (it will compensate for some of the contamination effects from harmonics and the like) and will give you a "more accurate reading" (without the distortion effects). The metrel will also allow you to view the harmonics and power factor for a supply.

The TM-EL9809 would be perfectly adequate for earth leakage in IT environments (appropriate resolution of 10microAmps and a 40milliAmp range) and has the hold, min, max functions (very useful when trying to find intermittent/quickly occuring faults).

 

[Jimmy Boy]

Thanks for your help
J

 

[HandySparks]

The resolution on the second link is only 10ma, you won't read 1ma.

You've misread it mate. The Metrel is a stonking bit of kit. Resolution is 0.01mA (not 0.01A).

 

[topquark]

You've misread it mate. The Metrel is a stonking bit of kit. Resolution is 0.01mA (not 0.01A).

Yep, I've got one

 

[i=p/u]

want one tooooooooooooooooooooooooooooooooooooooooooooooooo. 'because i do .

 

[snowhead]

You've misread it mate. The Metrel is a stonking bit of kit. Resolution is 0.01mA (not 0.01A).

Ah, mA on the next line, not a good way to promote sales.

 

[Jimmy Boy]

Perhaps I might go for the Metral then is it the 9270 you have Topquark ?
J

 

[topquark]

Perhaps I might go for the Metral then is it the 9270 you have Topquark ?
J

I have two clamp meters. I have the Metrel MD9270 and an AlphaTek TEK 633 (no longer available).

The Metrel has nice big jaws (slightly bigger internal space than a 50p piece). The AlphaTek only just fits on the tip of my thumb (so would be inadequate for anything over 35mm).

The only reason I bought the Metrel was because the AlphaTek had gone awol. I had lent it to a friend's son for an electrical problem on his car (it works with DC) and was convinced I had put it back in the van afterwards (but hadn't :banghead and they bought it around a couple of months after I'd purchased the Metrel.

Both quite capable of doing most jobs.

 

[MarkieSparkie]

I've got the Metrel MD9270 it's the dogs nuts mate. I tested just about every earth leakage meter on the market before making my decision and it was the stand out meter regardless of price.

 

[Jimmy Boy]

I've got the Metrel MD9270 it's the dogs nuts mate. I tested just about every earth leakage meter on the market before making my decision and it was the stand out meter regardless of price.

Thats very reassuring to hear, could you give me some examples of what types of circuits and /or faults these meters come in to their own ? TBH never seen the need for one up till now as most of my work is maintenance and smaller installs, now I am doing some IT circuits with high integrity earthing I feel the need for one.

Thanks J

 

[Engineer54]

With the amount of RCD's in service now and virtually included in every new CU/DB, i can't see how an electrician can be without a leakage tester.... An essential bit of test kit these days...

And this looks very much like my Di-Log (6330 i think) leakage tester... Re named manufacturer??... i'll have to have a check/look in the office tomorrow...

TM-EL9809 High Resolution AC Earth Leakage Clamp Meter

 

[Jimmy Boy]

Nice one 5-4
J

 

[HandySparks]

It's a useful tool where you can't, or don't want to, isolate the installation. Maybe just for a first look. For instance, a significant current down the main earthing conductor can indicate poor insulation resistance or a neutral-earth fault without having to disconnecting anything. You can learn a bit more by turning loads and circuits on and off and seeing how the current changes.

 

[Engineer54]

It's a useful tool where you can't, or don't want to, isolate the installation. Maybe just for a first look. For instance, a significant current down the main earthing conductor can indicate poor insulation resistance or a neutral-earth fault without having to disconnecting anything. You can learn a bit more by turning loads and circuits on and off and seeing how the current changes.

Why would you want to isolate an installation when your trying to find possible leakage currents that's affecting the operation of an RCD device?? Competently used, a leakage clamp meter can/will pin point abnormal sources of leakage current(s), as well as many other aspects, over and above those suggested above...

 

[spark 68]

a significant current down the main earthing conductor can indicate poor insulation resistance or a neutral-earth fault without having to disconnecting anything. .

Hi HS,

I find clamping the Earthing conductor misleading, as often you can measure more mA than it would take to trip a 30mA RCD even in a correctly functioning installation.

I wonder if this reading is actually imported ?

A better test is to clamp both tails as this shows how much leakage is present in the installation.
I often do this prior to a CU change, as any significant readings here shows that you will have to test much further before the change, as you are likely to have problems once RCD's are fitted.

 

[HandySparks]

Why would you want to isolate an installation when your trying to find possible leakage currents that's affecting the operation of an RCD device??

I don't know; I didn't say anything about an RCD.

But, for example, I knew that I had a problem that needed sorting before I replaced my old fuseboard with a new RCBO CU because I stuck the clamp meter on the earthing conductor and found amps rather than mA. All I'm saying is that, even on a domestic installation, it's a useful non-disruptive tool. When I actually came to pinpoint the fault, then it was a case of breaking down the circuit and getting the MFT out.

 

[HandySparks]

A better test is to clamp both tails as this shows how much leakage is present in the installation.
I often do this prior to a CU change, as any significant readings here shows that you will have to test much further before the change, as you are likely to have problems once RCD's are fitted.

Good point, I'd forgotten to mention that.

 

[Engineer54]

I don't know; I didn't say anything about an RCD.

But, for example, I knew that I had a problem that needed sorting before I replaced my old fuseboard with a new RCBO CU because I stuck the clamp meter on the earthing conductor and found amps rather than mA. All I'm saying is that, even on a domestic installation, it's a useful non-disruptive tool. When I actually came to pinpoint the fault, then it was a case of breaking down the circuit and getting the MFT out.

OK, ...my mistake, i understand what you were saying now. lol!!!