what happened here then, no power to meter

[rjm2k]

had a boiler changed yesterday, vented to combi, so the immersion supply is now looking for a use. the fitter left the mcb off, this morning I wanted to check that the supply was still connected to the immersion switch by checking the the red light. switched the mcb on, went to the old immersion switch and flipped it. everything went off. went to the consumer unit, the mcb and the rcd had both tripped. made sure the immersion switch was back in the off position and reset the rcd. lights flickered on briefly and went off again, the rcd probably tripped again but i can't remember, anyway no power. switched every circuit off by mcb, tried one of the light circuits still nothing, now the rcd stays in the on position.

i called a sparkie who has done some work for me in the past, he popped round, no power to the meter. call the grid, a guy comes out, goes next door where they had also rung in about no power (our feed dog legs off theirs). a couple of times it looks like it's starting up, but flickers off. eventually, it's back, guy wonders round to see me, asking if it's ok now. i ask what the problem was, he doesn't know, he didn't do anything, it just came back.

he suggested a dry joint in an underground cable may have gone and the re-welded itself?

apparently, some unexpected trips occurred while the boiler fitter was at work in the airing cupboard, but it came back straight away.

what is the likely cause and what implications are there for the future? neutral/earth issue?

strange that the suppliers fuse didn't blow.

the sparkie will be coming back to look at the immersion circuit which will stay firmly off until then!

thanks

 

[AndyPRK]

They don’t when there s no power

 

[rjm2k]

I would switch off the main switch and take the unused immersion switch off and check the wiring. It sounds like a bad connection in the supply to your properties. If the immersion switch wiring was shorted out the fault current may have caused the already poor connection in the mains supply to become intermittent. Are you saying the RCD now does not switch off , when you use the 'test' button? If so, that needs checking asap.

Kind regards,

John

i will check the rcd test button in the morning.

Andy, not sure what you mean, I rang the grid to report the cut as did my neighbour.

the guy from the grid didn't seem concerned or surprised, just said about a joint sorting itself out and that he couldn't say if or when it would happen again. he didn't do any tests at the meter for my property, but could have done next door as he was there for 10 mins maybe

strange thing is we used the immersion heater a number of times with no issue at all

thanks

 

[RF Lighting]

Sounds like you’ve had a dead short on your installation, and the 1000’s of amps this caused to flow through the network cable has blown a joint apart. If your power is back on now, don't expect it to last too long until it becomes intermittent or fails again.

 

[rjm2k]

Thanks for the input, hopefully nothing damaged in the property at least, seems strange that a 16a breaker, 22 amp cable, RCD, consumer unit busbar and suppliers fuse were not the weakest link in this situation

 

[winston1]

Thanks for the input, hopefully nothing damaged in the property at least, seems strange that a 16a breaker, 22 amp cable, RCD, consumer unit busbar and suppliers fuse were not the weakest link in this situation

It all depends on speed of operation. RCDs don't trip on overload. All the other things you mentioned will probably be OK at 1000amps for a micro second.

 

[rjm2k]

rcd test button works ok