Neighbours rcd tripping

[bobbies_girl]

I am renovating a rural cottage and have replaced the consumer unit, rewiring the lights and sockets. Also the Electricity board have moved the overhead cable to the house to one that now goes underground. Over the last 2 months, our neighbour (whose electric comes from the same telegraph pole) has complained of nuisance tripping. Apparently, the nuisance only occurs when we are resident in the house and not at other times. However, our consumer unit does not trip on a nuisance basis but appears to trip correctly when a bulb goes etc. As the nuisance tripping did not occur before we moved in (and the neighbour agrees the electrics were in a poor state then !) he feels the problem is of our making. We cannot see how to resolve this. We have tried to force a trip by turning appliances etc on and off but to no avail ! Our neighbour has a whole of house 30ma RCD - could this be anything to do with it ?

Help !

 

[Adam_151]

Ah, an interesting one

Sorry to start off by going technical, but it would be very usful to know what the earthing arrangements are for both you and your neighbour

TT? (earth from an electrode in the ground), TN-S? (suppiers earth connection back to local distrubution transformer), TNC-S? (suppliers earth connection derived from neutral)

Easiest way would be probably to take pictures of the meter and consumer unit areas and post them here and we can identify what earthing method it uses

Also is it a rural or urban area? (ignore that one, I've now read your post properly )

 

[Steve]

yes. 30ma is too sensitive for a whole house, but some less considerate sparks still fit them. If the supply has been changed to underground the DNO could provide a TNCS or TNS supply, which doesn't require a whole house RCD.

Out of interest, do you know the earth arrangements of both properties? Do you have earth rods? Has the DNO changed any equipment in your homes? Can you post a picture of your service head (mains incoming)?

 

[securespark]

Could just be a complete coincidence.....

Maybe they're trying it on?

Ask them to eliminate their installation before you put effort into looking for a problem with yours.

Tell them to get a PIR done. After all, it's THEIR RCD tripping, not yours..

 

[sparkman]

yes. 30ma is too sensitive for a whole house, but some less considerate sparks still fit them.

A 30 mA is for shock purposes and is not too sensitive for a whole house however the lights should not be on it where posible (a split board should ideally be used)

What you probably need to look for is a loop supply from your main fuse to theirs and as already mentioned check the earthing arrangements.

It would also be useful to test the trip time of the RCD using an RCD tester.
It should not trip at 1/2 the current rating of the RCD
it should trip within 200mS at the current rating of the RCD
and at 5 imes the rating it should trip out in less than 40 mS
hope this helps.
sparkman

 

[JohnD]

I am also of the opinion that a single 30mA RCD for the whole house is over-sensitive

There will be a constant slight leakage from stuff like washine machine, immersion heater, kettle, outside lamp, shed supply, and it needs little extra to take it over the trip. Sometimes a computer or microwave will do it. If theirs is an old house with old wiring or old appliances, their background leakage might be quite high (from memory, mine has a backround of about 10mA, most from the ground floor ring, especially the washing machine, and some was from the immersion heater which has since been replaced, with a small but detectable leakage from the cooker).

It might possibly be that there is something in your house that affects the neighbours.

Do you, and they, have a good main bonding to the water and gas pipes; is it the same water and gas pipe?

 

[bobbies_girl]

thanks guys you've given us plenty to look at, and hopefully convince the neighbour we're not deliberately trying to upset him (but I can imagine the electric going off 10 times a day can be really annoying!)
hubby believes the earth goes back to the transformer, will check all the other suggestions