Tripping electrics

[DetlefSchmitz]

As it happens everything here is RCD protected except a couple of indoor fridges/freezers (not the one in the garage). The RCD did not trip.

That's rather amazing. If water was creating an L-N path that was somehow carrying 36A+, it would seem very unlikely that 30mA would not get from L to E!

I know - all I can do is report what happened!

I think I knew within seconds as the internet router is powered from the same circuit, and I was tracking the lightning strikes. Guaranteed to get an instant reaction in our house if we lose the circuit powering the internet. So less than 5 minutes to trip the MCB.

I'm not sure that you're answering the question I asked - namely how long it was from when the water hit the freezer electrics to when the MCB tripped. You're surely not saying that the water level in the grage got high enough to recah the freezer's electrics within 5 minutes of the rain starting?

Yup - It was the worst storm we have ever had here. Storm start to trip 5 minutes. Almost unbelievable.

Probably need to look for a way the freezer could take a large current when water covered the motor. Maybe the motor wouldn't turn.

I'm not sure what you are suggesting here. IME, the compressors of fridges and freezers are invariably totally enclosed/sealed - so there's no way that external water can get near any moving parts. Are you perhaps suggesting that a short through water reduced the voltage supplied to the compressor to a low enough level that it could not turn, yet with a voltage still high enough that "tens of amps" could flow through the non-turning motor?

Once again - I don't know - all I can do is report what happened! When I have looked at the stuff behind a freezer - it doesn't looked that sealed. But I don't have any facts to report in that area.

Edit: one further thought - are you sure that it was the water, and not lightening, which caused the MCB to trip? (it's not uncommon here for both RCDs and MCBs to trip when there is nearby lightning - presumably due to interference with their electronics)

As said the MCB would not close, until we unplugged the freezer. Then it closed immediately.

This is definitely an MCB - I installed it myself 7 years ago - everything MK for what it's worth.

 

[JohnW2]

Yup - It was the worst storm we have ever had here. Storm start to trip 5 minutes. Almost unbelievable.

That's amazing.

Once again - I don't know - all I can do is report what happened! When I have looked at the stuff behind a freezer - it doesn't looked that sealed.

The electrics behind a freezer certainly aren't sealed (I had a similar experience to yours with a freezer in the cellar - which tripped an RCD when the water level rose), but I've never seen a compressor that was not seemingly 'sealed'.

As said the MCB would not close, until we unplugged the freezer. Then it closed immediately.

So much for my lightning-triggered-trip suggestion, then, I suppose!

Kind Regards, John

 

[Iggifer]

All compressors are sealed, the only thing that is liable to water ingress compressor wise is the cap and maybe a PCB which is generally in a small plastic box on the side.

 

[JohnW2]

All compressors are sealed, the only thing that is liable to water ingress compressor wise is the cap and maybe a PCB which is generally in a small plastic box on the side.

Thanks. As I said, that corresponds with my experience.

Kind Regards, John

 

[Kez6670]

Ok so electrician has been this morning. Had all the sockets off. All he could find was a fault with a socket in the conservatory which was showing on his beeping machine! I don't need that socket so he has disconnected it. Not sure if this has solved problem. Electric is on now but it has been on previously for a couple of days with no tripping so only time will tell. He was here just under 3 hours charged £120. Was happy with that.

 

[Iggifer]

Did his 'beeping machine' look like this?

If so I'm worried.

 

[Kez6670]

No it was two red pen things connected by a wire

 

[Echo the husky]

Something like this????

 

[Kez6670]

Yes that's right.

 

[deadshort]

Still worried

DS

 

[securespark]

Give me strength...

 

[Echo the husky]

Give me strength...

I didn't quite know how to react to someone using a voltage tester to locate this fault, but I'm now going with total despair.

 

[Iggifer]

I want to know a) what fault he diagnosed and b) how he resolved it by removing a socket

 

[EFLImpudence]

I suppose he could have detected a permanent variable short in a socket.


However, the fault wasn't permanent - perhaps he was lucky. We shall see.

 

[Echo the husky]

Perhaps, even so that would not be my weapon of choice.