Advice -Kewtech KT64DL multifunction test meter ? RCD test ??

[bilabonic]

Hi all

I’m an industrial spark by trade but just got purchased a cheap KT64DL.

4 year apprenticeship
ONC
HNC
HND
Degree

I’ve always used flukes/meggers in heavy industry so this is new to me.

I did do my 16th Ed when I started in 1991 but since then I’ve dealt with industry stuff. PLCs. SCADA. Motors. Every type of sensor/relay/contactor /etc etc can imagine. Upto 11Kv.

I’ve just watched this video on testing an RCD on a live RCBO.

It gives the trip times but not the trip value in mA? Or am I missing something?

Cheers

 

[flameport]

Trip times is one test
Actual trip current is another one.
The KT64DL and most other RCD testers can do both, but they are separate things, not done at the same time.

 

[bilabonic]

What is the process to measure for trip current?
I’m getting nuisance trips on my old Wylex RCD.
Obviously set to RCD and connect as usual.
Just unsure what to select on the F1 to F4 buttons?
I presumed the auto test would display trip times AND trip current when set to auto??

I know the old Megger I had used to.

Anyone advise.

Cheers

 

[ericmark]

The point I would question is since the RCBO is connected to a circuit, there will be some leakage on the circuit, so one needs to test what that leakage is, if you had a 15 mA leakage OK the test should trip at the half setting, but with say a 7 mA back ground leakage you are actually testing it is tripping at 37 mA not 30 mA.

In the main we see much lower, so a 2 mA leakage maybe can be ignored, a ramp test will likely show it trips at 27 mA or less, so still 1 mA within limits, but one can't simply ignore the back ground leakage.

With a RCD no problem, all MCB's can be turned off, but with a RCBO one can't remove the load, if you disconnect the output cables then the action of refitting can alter the readings, as I have found with RCD's, the cable can cause a strain on the device which can cause it to go out of spec.

It takes seconds to put the clamp on around the cables and show there is no back ground leakage or if there is it is minimal, so why would any collage produce a video and miss out that step?

I seem to remember there was a change as to type settings on the RCD tester, and also the requirement to do the 6 tests we did in my days of doing the C&G 2391, opening up the video in Youtube it does say it is 7 years old. So one can expect it to be out of date.