How do use one of these please.....

[sythai]

Evening chaps...

Sorry have searched this but getting late and cant find what I'm looking for (just finished my paperwork - going cross eyed here :rolleyes4::rolleyes4

Seem to be doing a fair bit of fault finding lately - nuisance tripping being a common a one.

So think one of these may be useful for me : earth leakage clamp meter

But just wondering before I buy how do actually use it.... I presume you clamp round the earth core and see what mA it reads - but how would you do this with an appliance ?

Many Thanks,

Sy

 

[tony mc]

You would have to use a extention cable and take off the outer insulation then you would be left with the line neutral and cpc.

Clamp the line and neutral with the meter and check the leakage if any or clamp the cpc.

For the instalation clamp the tails at the meter !!

 

[telectrix]

yes, you clamp it round the earth (or cpc, to be pedantic). for an appliance you can clamp round either the cpc in the CU of the circuit on which the appliance is connected to, or even clamp round the main earthing conductor, then switch the appliance on. obviously, you would set the meter on the mA range,

 

[GLENNSPARK]

Make up an short extention lead with a loop of cpc pulled out of it about half way along then taped up where you cut it to get the cpc out. You should be able to get the clamp around the cpc ok to measure...

 

[topquark]

You can also clamp around line/neutral (both conductors) that will give a differential reading (in case your leakage is going somewhere other than down the cpc).

 

[GLENNSPARK]

That being the difference between the two is the earth leakege topquark....My mft will measure earth leakege direct so i can use a three way plug and take measurements direct using a 1363 plug.......

 

[topquark]

Doh! Not if it's not going down the cpc it's not....that's the whole point of doing it!

 

[GLENNSPARK]

Yes of course mate.....

 

[topquark]

That's one of the reasons that most RCBO's are designed to look at current inbalance between line/neutral (or phase/neutral in 3ph) rather than measuring leakage on the cpc. Coz you can't guarantee that any leakage is going via that circuits cpc. Admittedly the first port of call is to check the cpc, but don't assume that's where all of the leakage is going

 

[sythai]

Thanks chaps for all your replies there, great help as usual :yes:

In the meantime have also found where I posted on here about this once before - whoops sorry :willy_nilly:

http://www.electriciansforums.net/electrical-tools-products/17451-earth-leakage-clamp-meter.html

Sy

 

[sythai]

Just another questions re : using it ?

Sorry if this sounds a bit blonde ....Can you only pick up earth leakage when you have the circuit energised ? If so how would check circuits that you are unable to energise due to RCD not holding - move them on to an unprotected way if available maybe, but if not ? Thank you.

Well put my order in for one of these... only a cheapy, but should be good enough for what I need

Dilog DL6507 10uA to 60A AC Leakage Clamp meter. Buy online or call

 

[tony mc]

If the RCD will not hold I would be disconnecting ccts one by one making sure the line and neutral is disconnected.

Then once I had found the cct causing the fault IR test it and start looking for the fault.

The IR between either Line or neutral will have to be below 7666 ohms or their abouts 230/0.03 if its a 30 mA RCD.

 

[topquark]

Hi Sy, IR testing is the tool for an unenergised circuit. Clamp meter for an energised circuit. If you're contemplating a change to a non RCD/RCBO protected MCB then you should IR test the circuit first.

I often find that the cause of tripping is down to an appliance and keep one of these in my response bag: Kewtech PATADAPTOR1: Convert 17th Edition - PAT Adaptor 1

It enables you to do a quick (soft) IR test on a suspect bit of kit (not definitive but often helps).

 

[sythai]

Right thank you got it..... understand now

 

[sythai]

Happy with that arrived today, not bad for £120, just couldn't justify spending £300 on a megger for the amount of time I will use it.
Bit of random/ intermittent rcd tripping on Wednesday to look at, so we'll see how I get on