mA Tong Tester recommendation cheapo.

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roys

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Story first:

Fitted an RCBO board in my own house about 18 months ago after I rewired it, every 2 or 3 months the kitchen/ until ring 32A RCBO will trip. IR on circuit is perfect, now checked IR several times, had most of the face plates back off, checked that no insulation was pinched, thought I had found it, put a bit of sleaving on the very slightly marked insulation couple of months ago. but got a random trip yesterday. Couple of times the trip has been when the combi was running, once the washing machine was on final spin function, once tumble dryer was on, so can’t get any consistency on the trip. New combi, new fridge freezer, new tumble dryer, not so new washing machine but that was only on for one of the trips (yesterday’s).

Put my ancient RCD tester on the circuit, x1 tripped at 36mS, x1/2 no trip.

Next step to me is to put a mA tong tester on it to see how much leakage is on circuit in case there is high general leakage on the circuit and when something else fires up it is enough to trip it over the edge.

If there is high leakage it gives me something to hunt down, if not then change RCBO, then next mmmmm

So back to start, I want to buy a cheapo, fairly accurate mA clamp on tester. I am retired so it won’t be getting much use, so don’t want to be spending £100’s on a tester I will hardly use or be getting calibrated annually, seen the Uni-t UT210 at about £35 anyone got one, any good or any other suggestions.

Cheers chappies

 
I've got the Amecal earth leakage tester, quite cheap as these things go. Not had a lot of use out of it but it seems ok and I bought it on recommendation from other sparks in a group I'm a member of. 

Link here  https://www.ebay.co.uk/itm/AMECaL-ST-9810-Mini-AC-Earth-Leakage-Current-Clamp-Meter-Tester-Equiv-TEK775/173733930467?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

I too looked at the UNI-t things due to their price but was put off by some bad reviews of them, that's not to say they aren't any good for what you need though.

 
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Thank you for that, good call. Under a £100 so comfortable with that.

Curiosity got the better of me, When my wife was out this morning, I switched of all the breakers, removed the 10mm earth to gas, none on water as it’s all plastic, and removed earth to board and put my Fluke on mA in series with it, read 1mA, I then put on just the RCBO that was causing the problem, the reading went up to 7.5 mA,

switched of double pole to tumble dryer down to 5.5 mA,

then switched off double pole to washing machine down to 3.5mA

then switched of double pole to combi down to 2.5mA

So nothing dramatic there just the SMPS on the equipment with slight leakage as expected.

Had a bang along the plasterboard following the cable route with meter on min/max, no change.

so next step replace the one usb socket on that circuit, leave for say 6 months to see if it trips, if it does replace RCBO.

I hate random changing but I have done testing with no fault found.

When I go away from home for anything more than 2 days I will plug the fridge freezer into the downstairs radial.

Think I need a datalogger as well 😀

 
My ancient RCD tester can’t tell me that, it just tells me that no trip at 15mA, and at 30mA it trips at 37mS, and I ain’t buying a new one😀

No ramp test facility I’m afraid.


Oer.

Can't you borrow one of a mate?

Without a ramp test you won't know what you are dealing with

 
Had a bit of handy angle lying in my shed for decades never threw it out cos “it will come in handy” well a month ago I used it, painted it white and fitted it along a wall to support a kitchen worktop to make a desk, couldn’t do the usual of use a bit of batten as it had to be slim line so that a drawer unit could fit neatly under. Worked a treat.

 
Had a bit of handy angle lying in my shed for decades never threw it out cos “it will come in handy” well a month ago I used it, painted it white and fitted it along a wall to support a kitchen worktop to make a desk, couldn’t do the usual of use a bit of batten as it had to be slim line so that a drawer unit could fit neatly under. Worked a treat.
We seemed to use miles of it once  upon a time ...mostly frames for switchgear  etc  .      If I remember correctly  it became an expensive item .  

 
What was the lightweight version that was a copper/bronze colour?
We just used to call that handy angle or Dexion as well, either light duty or heavy duty.

Remember using it to make supports for cable tray as well as bending and welding flat bar for brackets in the early 80’s, then I moved jobs and was introduced to Unistrut.

 
Thank you for that, good call. Under a £100 so comfortable with that.

Curiosity got the better of me, When my wife was out this morning, I switched of all the breakers, removed the 10mm earth to gas, none on water as it’s all plastic, and removed earth to board and put my Fluke on mA in series with it, read 1mA, I then put on just the RCBO that was causing the problem, the reading went up to 7.5 mA,

switched of double pole to tumble dryer down to 5.5 mA,

then switched off double pole to washing machine down to 3.5mA

then switched of double pole to combi down to 2.5mA

So nothing dramatic there just the SMPS on the equipment with slight leakage as expected.

Had a bang along the plasterboard following the cable route with meter on min/max, no change.

so next step replace the one usb socket on that circuit, leave for say 6 months to see if it trips, if it does replace RCBO.

I hate random changing but I have done testing with no fault found.

When I go away from home for anything more than 2 days I will plug the fridge freezer into the downstairs radial.

Think I need a datalogger as well 😀
Testing for earth leakage on the main earth cable is ignoring all the possible parallel leakage paths at the metal accessory back boxes.

Only reliable way to measure the leakage current is to put a tong tester round the incoming live and neutral to measure the differential (earth leakage) current

I would normally suspect a fault with the fridge freezer but the tripping seems too infrequent to suggest the auto defrost element is failing or has failed, the auto defrost usually kicks in every 24 - 72 hours but varies across different appliances and doesn't always trip the RCD / RCBO every time and for that reason can be difficult to identify as the fault as once tripped the auto defrost relay resets

 

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