Megger 1730 MFT. Not tripping on any RCD tests on known good circuit.

Marti · Oct 30, 2018

G'd Evening Lads an' Lasses,
I've got a Megger 1730 MFT; lovely bit of kit normally. Ex-demo - not had a hard life and was calibrated about eight weeks ago. I normally run it over a Cal-Card and a captive test RCD about once a month and this time it failed to trip the 30ma RCD on 1x, 5x and ramp. Tested all the RCD's in the house - same result. Reset everything to default - same result.

Has anyone seen anything like this? Really appreciate your thoughts. just started out on my own so the timing is ERR...unfortunate if it's terminal.

Marti · Oct 31, 2018

Hi Pete,
Tried both. The meter skips from test straight into the timer. Our 1720 comparison unit on 1/2 delta tested for 3 - 4 seconds then counted. Mine went straight to count. The 1720 then tripped on 1x and 5x delta. Mine just counted so it's going to Alpha.

Pete999 · Oct 31, 2018

Marti said:
Hi Pete,
Tried both. The meter skips from test straight into the timer. Our 1720 comparison unit on 1/2 delta tested for 3 - 4 seconds then counted. Mine went straight to count. The 1720 then tripped on 1x and 5x delta. Mine just counted so it's going to Alpha.

OK thanks, are the outgoing circuits still energised?

Billsays · Oct 31, 2018

Marti said:
Update on the poorly Megger.
Took it into Barking and Dagenham College (did my C&G there) They tested my MFT and leads on a college rig with a known good 1720. Definitely a faulty unit. The only question is whether I caused this switching between functions whilst powered? Don't know but probably worth bearing in mind. Thanks for all the input guys.

Hi Marti,

Have you tried dropping it in to these guys.......

Test Instrument Calibration - Electronic Instrument Calibration Repair - Essex, UK - http://www.capitalcalibration.co.uk/

They are pretty helpful and calibrate and repair our testers all the time.

Marti · Oct 31, 2018

Hi Pete,
Tried both. The meter skips from test straight into the timer. Our 1720 comparison unit on 1/2 delta tested for 3 - 4 seconds then counted. Mine went straight to count. The 1720 then tripped on 1x and 5x delta. Mine just counted so it's going to Alpha.