Rcd Main switch blown by Ze test

[Mikey10695]

Hi all just wondering if I could pick you brains, I was doing a ze today on a consumer unit, 80amp rcd main switch, (the test button wasnt functioning so I was already thinking as to what caused this to blow) I disconnected the main earth, turned the main switch into the off position, I then went to test between line and earth & as soon as I put the probe in the live terminal its blew the main switch & my probe completely, any idea as to why this happened? Im yet to come across an issue when carrying out a ze test, cheers.

 

[UNG]

Your post is a little sketchy as to what you have done
What exactly do you mean by blew the main switch and my probe, I'm assuming you were testing on the incoming side of the main switch when this happened
Does your meter still function and what model is it

 

[Baddegg]

As above when someone says “blown” a main switch to me I always assume something has tripped but you say the switch was in the of position already? Are you sue the meter was in Ze test mode?….

 

[littlespark]

If it was a Ze test, where was the neutral probe at this time?

Even with the mainswitch off, it could still be “on” inside, even on only one pole.

 

[timhoward]

From the little info given, the pertinent questions (already asked) seem to be what tester do you have and are you sure it was not in continuity or IR modes when you put the probes on?

 

[timhoward]

The only other thought is what type of RCD main switch was it? If you say Square-D I deserve an award for telepathy!

 

[Mikey10695]

The only other thought is what type of RCD main switch was it? If you say Square-D I deserve an award for telepathy!

 

[Mikey10695]

Hi it was an ashley and rock 80amp main switch rcd

 

[Mikey10695]

From the little info given, the pertinent questions (already asked) seem to be what tester do you have and are you sure it was not in continuity or IR modes when you put the probes on?

Hi I have a dilog multi meter, it was in ze mode, ive tested other properties all is fine, I switched off the main switch, disconnected the pain earth, as soon as I put a probe in the incoming live terminal the switch sparks and blows, it also took the end off my probe

 

[Mikey10695]

If it was a Ze test, where was the neutral probe at this time?

Even with the mainswitch off, it could still be “on” inside, even on only one pole.

I didnt have the neutral probe connected at the time, as I was testing between main income line and the main earth

 

[Mikey10695]

As above when someone says “blown” a main switch to me I always assume something has tripped but you say the switch was in the of position already? Are you sue the meter was in Ze test mode?….

Yes the meter was in ze mode, as soon as i put the probe in the line terminal its sparked, banged and blew the probe too

 

[Mikey10695]

Your post is a little sketchy as to what you have done
What exactly do you mean by blew the main switch and my probe, I'm assuming you were testing on the incoming side of the main switch when this happened
Does your meter still function and what model is it

Meter still in working order, I was testing on the incoming line amd main earth, it sparked, bamged and blew the end off the probe as soom as I inserted the probe into the line terminal, the main switch was off, could this be a dodgy main switch rcd as the test function was not initially working

 

[Lister1987]

Hi I have a dilog multi meter, it was in ze mode, ive tested other properties all is fine, I switched off the main switch, disconnected the pain earth, as soon as I put a probe in the incoming live terminal the switch sparks and blows, it also took the end off my probe

Can you do a PSSC on incoming live and neutral to prove the meter (and leads and probes) still function? Are they fused leads or just a fused MFT [I'm assuming here]?

 

[Mikey10695]

Can you do a PSSC on incoming live and neutral to prove the meter (and leads and probes) still function? Are they fused leads or just a fused MFT [I'm assuming here]?

As soon as I insert a probe on the line, it blows, the tester does Ze, with pfc at the same time.

 

[plugsandsparks]

Caught the side of the probe on N or E, only thing i can think of which would cause sparks and a damaged probe but not a damaged meter.