Main fuse tripped

TMSG

Yesterday evening, ~9pm, the main fuse (80A) in our fuse box tripped. At that time, we had one small laptop running on mains, one lamp of ~10W, the internet router and a DECT phone and nothing much else, no TV, no kettle, no oven. Perhaps the freezer was running but as that's in a different room I can't say. So I went to the box, saw the tripped main fuse (none of the other fuses had tripped) and simply put it back. Nothing happened (ie it didn't trip again) and leccy was restored. This has never happened before and today, there was no further problem either, with kettles, fridge and freezer etc etc all running as normal.

I am now wondering what the reason for this could have been as 80A is rather a lot Some incoming peak from the grid? Or what else?

GDB2222

I'm guessing there's an electrocuted rodent somewhere in your house.

fenwick458

I'm guessing it was an 80A 30mA RCD main switch? if it is, then the 80A part is not relevant, thats just the current it's rated for. the 30mA is the important part, it will have tripped because more than 30mA of current has leaked to earth.

GDB2222

fenwick458 said:

I'm guessing it was an 80A 30mA RCD main switch? if it is, then the 80A part is not relevant, thats just the current it's rated for. the 30mA is the important part, it will have tripped because more than 30mA of current has leaked to earth.

Really? Can I ask the OP what colour the switch was that tripped?  Was it red?

fenwick458

GDB2222 said:

fenwick458 said:

I'm guessing it was an 80A 30mA RCD main switch? if it is, then the 80A part is not relevant, thats just the current it's rated for. the 30mA is the important part, it will have tripped because more than 30mA of current has leaked to earth.

Really? Can I ask the OP what colour the switch was that tripped?  Was it red?

yes I think it would be helpful if the OP cleared it up

this is an 80A RCD


this is an 80A fuse


the fact that it was reset implies it was not the fuse. correct terminology helps here, IMO the first line should read "the main RCD tripped"
I've been present when 80A fuses go off and it sounds like a grenade, and I was in the army so I know what they sound like too

GDB2222

The op said "the main fuse" but I agree, thinking about it, that he may have just meant the RCD. 

TMSG

OK, I apologise unreservedly for saying "fuse" when the item in question is called "RCD", won't happen again.

As to the problem: the RCD (yes, 80A/30mA, grey switch with a yellow test button next to it) tripping has now happened again, and through a not so quick process of trial and error I have tentatively identified a kettle as the probable culprit (tentatively and probable because it only happens when the kettle is connected to the mains and not when it's disconnected -- but this is not 100%). The kettle doesn't have to function, it just sits in its cradle and the cradle is connected to the mains.

Section62

TMSG said:

As to the problem: the RCD (yes, 80A/30mA, grey switch with a yellow test button next to it) tripping has now happened again, and through a not so quick process of trial and error I have tentatively identified a kettle as the probable culprit (tentatively and probable because it only happens when the kettle is connected to the mains and not when it's unconnected -- but this is not 100%). The kettle doesn't have to function, it just sits in its cradle and the cradle is connected to the mains.

Water getting into the kettle base (or a similar fault) could cause a RCD to trip, even if the kettle isn't being used.

Buying a new kettle (and seeing whether the fault repeats) will probably be cheaper than getting an electrician to investigate.

[Deleted User]

Hi,

does it happen if cradle is empty, kettle removed?

grumbler

Section62 said:

TMSG said:

As to the problem: the RCD (yes, 80A/30mA, grey switch with a yellow test button next to it) tripping has now happened again, and through a not so quick process of trial and error I have tentatively identified a kettle as the probable culprit (tentatively and probable because it only happens when the kettle is connected to the mains and not when it's unconnected -- but this is not 100%). The kettle doesn't have to function, it just sits in its cradle and the cradle is connected to the mains.

Water getting into the kettle base (or a similar fault) could cause a RCD to trip, even if the kettle isn't being used.

Buying a new kettle (and seeing whether the fault repeats) will probably be cheaper than getting an electrician to investigate.

You don't need an electrician to check the base and dry it if needed. Unplugged, of course.
The only problem can be with security screws (if any), but even without a matching screwdriver  bit they can usually be removed with a right size flat screwdriver

FreeBear

TMSG said: I have tentatively identified a kettle as the probable culprit (tentatively and probable because it only happens when the kettle is connected to the mains and not when it's unconnected -- but this is not 100%). The kettle doesn't have to function, it just sits in its cradle and the cradle is connected to the mains.

I had a kettle that got turned on without any water in it. Soon after, it kept tripping out the mains... It could be what happened with your kettle.

New ones are not expensive.