mA Tong Tester recommendation cheapo.

[roys]

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

 

[boltonsparky]

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.

 

[roys]

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

 

[Murdoch]

OP what ma value is your rcbo tripping at?

 

[roys]

OP what ma value is your rcbo tripping at?

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.

 

[Murdoch]

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

 

[roys]

Oer.

Can't you borrow one of a mate?

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

Yip I sent out the sos to my mates last night for a mA tong tester and a RCD tester with ramp test.

 

[Murdoch]

Yip I sent out the sos to my mates last night for a mA tong tester and a RCD tester with ramp test.

Tong ?

 

[roys]

Tong tester = clamp on ampmeter, 

is that just a Scottish term?

 

[Murdoch]

Tong tester = clamp on ampmeter, 

is that just a Scottish term?

That's a new one on me!

Ramp test, RCD trip times, Ze, Zl then earth leakage tests first

Especially on dual RCD boards 

 

[Geoff1946]

Tong tester = clamp on ampmeter, 

is that just a Scottish term?

Not Scottish, maybe just old. I knew it and I'm Lancashire born, bred and employed. 

I've always assumed it's because the jaws form a pair of tongs, like fire tongs. (I'm not sure if there should be a U  in there}

 

[Evans Electric]

I knew them as Tong Testers when an apprentice  ,  huge things with a pair of ...you guessed it ....tongs  

 

[kerching]

Tong ?

Yep Tongue testers...always have been called that here

On a tangent....rang wholesalers for a length of 6 mil stud today....nobody knew what I meant!  Is it just me?

 

[Evans Electric]

Well its me too in that case .       I suppose he understood  6mm threaded rod   or All Thread .  .     Try asking for some "Handy Angle"     or Dexion .   

 

[roys]

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.

 

[kerching]

I have had to start ordering ".earth sleeving " as Green Sleeve is a special colour order!  WTAF I blame Brexit and Trump!

 

[Evans Electric]

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 .  

 

[kerching]

What was the lightweight version that was a copper/bronze colour?

 

[roys]

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.

 

[UNG]

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