RCD tripped

Kaisr Sose

My RCD tripped today for no apparent reason. All.that was on at the time was the fridge freezer, TV and sat box, gas boiler on standby and one light on. This would be very normal load during daytime. Would this just be a random trip or something else?

My gas boiler or light did not power off when RCD tripped. It just affected plugged items. I thought everything would go off if the RCD tripped (built 2005/6)

meercat

check your immersion is turned off

Not unusual that central heating isn’t rcd protected however on older installations. It is a regulation now however

Kaisr Sose

Thanks. I have a combi boiler so no immersion. Very low draw on the CU at the time of trip and anything that was on, had been on for hours prior to the trip. Odd!

My concern is it tripping again while I am on holiday and the ruining the contents of the fridge freezer.

AMKC

Is this the first time it ever happened? Are you sure there was no radios in bedrooms or other devices plugged in?

Maybe one of the plugs was slightly wet or damp and this caused it. You can rule the boiler and light out as these were not on RCDs back then unless you recently got your board upgraded in the last few years. I am guessing that you have not and it's just the one blue RCD switch and MCBs. So it was either one of the plugged items or you might have a mouse in the attack eating the cables or trying to lol. That could cause it too.

Kaisr Sose

https://www.boards.ie/discussion/comment/123149776#Comment_123149776

Thanks

100% only f/freezer, TV and sat box. No plugs were wet.. It was worth checking them.

It happened before but it was years ago. No mice that I am aware of. It's. 4/5floor apartment so mice or rats unlikely. No attic. I cannot vouch for what is in the ceiling void. The roof is a major problem in the complex and definitely letting in water, for years (16yrs actually!)

Moisture in the walls could be the cause. Today was wet, but by no means the first or only wet day this or last year. I have long believed that water is seeping downward from the roof over time. Units below me report issues with damp walls and window reveals that is from unknown water ingress

I just took moisture readings from an external facing wall and under kitchen cabinets where all sockets that were in use and got high readings near floor level but not at ceiling height. I will have to monitor this.

AMKC

Yes it could be the moisture in the walls then getting into your sockets. That coukd be causing the RCD to trip if there is no mice problem or attic. It could take time for the moisture in the walls to get to the sockets and have an effect. No idea how you could sort it. Maybe have someone check your apartment when you are away on holiday. Maybe try not to leave too much in the fridge or fridge freezer when away so if it does happen you will not loose much.

Kaisr Sose

I will try and follow up as much as I can on the moisture with the OMC. It's a real concern if the electrics in units are affected due to a legacy issue with the roof. This is part of a building redress project that is in negotiations since 2009/10.

I know there is moisture in the wall cavity as a curtain pole fitting fell off the wall last summer. The screws holding it had rusted and failed. There was no visible damp on the wall!

We always try to empty the fridge and freezer as best we can before a vacancy for 3 days plus. Now even more so!

cuculainn

You could put the freezer on its own RCD. If the fault isn't on the freezer circuit, then the RCD tripping won't impact freezer

meercat

it’s possible that moisture has seeped into the cabling/ sockets

This could cause rcd tripping

It could also trip if an appliance is plugged in(it doesn’t have to be actually turned on)ie kettle toaster dishwasher microwave etc. it’s generally something with an element though

a competent rec doing an insulation test should find it for you though

Kaisr Sose

https://www.boards.ie/discussion/comment/123150427#Comment_123150427

Thanks. That interesting. So I can add coffee machine, kettle, washer dryer and two lamps. All these wounlld be plugged in every day the past x no of years and not cause a trip, but yesterday, the RCD tripped. I think it may be moisture in the wall. How easy/difficult is it to prove this is the cause?

meercat

https://www.boards.ie/discussion/comment/123151300#Comment_123151300

it’s generally a neutral to earth fault that causes the rcd to trip. Neutrals and earths aren’t generally switched so if an appliance is plugged in it can still trip the rcd even when switched off.
An Insulation resistance test can usually identify the faulty circuit and a process of elimination can begin from there.

tom1ie

Lights aren’t on the RCD.
Did you lose power to all sockets?
If so it was the RCD alright- which suggests an earth fault.
The fridge freezer would possibly be the culprit I’d imagine.

Does the RCD stay on when you push it back up or does it trip again straight away?