Neighbour trips my RCD?

[securespark]

It was common in the 1950's to use a single service cable from the street cable to pairs of semi-detached houses.

Seen it done in very recent years (2012 in Sheff) with 35mm² straight con feeding one house and a short length of 25mm² looped through to next door.

 

[ban-all-sheds]

It was common in the 1950's to use a single service cable from the street cable to pairs of semi-detached houses.

My street, of that vintage, is wired just like that.

 

[Lectrician]

My old house was done like it, 25/16 though.

I've seen this type of fault a couple times, it's been because of a N to E fault on the non RCD side, TN-S install, common earth path between buildings. Difficult to explain why....

What type of RCD? Is it the type with an earth fly lead?

 

[bernardgreen]

A picture of the cut out ( supply fuse ), meter and consumer unit would help to narrow down the reason for the RCD to trip.

If there is a section of shared Neutral and that section of cable is concentric with spiral laid Neutral

Having just examined a bit of BS 7870 35mm² Aluminium the Neutral has very little twist ( spiral ) so inductance of the Neutral would be negliable in terms of creating current differentials in the RCD sense coil. Whether split concentric has more twist I do not know.

 

[DaveHerns]

Why would it only be the lawnmower that causes the problem? Why not similar appliances , eg a pressure washer or large vacuum cleaner ? Does this mean the neighbour's mower can be repaired/modified to prevent this tripping?

 

[bernardgreen]

Why would it only be the lawnmower that causes the problem?

That was why I asked where the mower was when the RCD tripped. On wet grass the sneak path could be from the mower via the wet ground and it would not be there if the mower was on dry concrete. Is it a new mower without an Earth or one that does have an Earth connected to it's metal work ?

 

[gavski34]

I assume he doesn't mow on wet ground or concrete. It is quite a cheap old machine, my assumption is there is excessive arcing over the poles. I would have thought all mowers would have an earth?
This has given me an idea though - I have an RCD plug adapter. if he runs it through this it should make it trip if it's faulty.

 

[ban-all-sheds]

I would have thought all mowers would have an earth?

No.

This has given me an idea though - I have an RCD plug adapter. if he runs it through this it should make it trip if it's faulty.

Not necessarily.

 

[securespark]

They might both trip simultaneously.

 

[ban-all-sheds]

I was going to say more about "Not necessarily", but a big boy running away with a dog set fire to it before I got here. Or something.

PBC_1966 said: ↑
Is it every time? When your RCD trips put, does his lawnmower immediately stop, or does it not affect him?

OP said: No, he's fine and just carries on mowing and whistling a merry tune It does it 3 or 4 times over the course of him mowing the lawn but it is every time he does it.​

(Sorry for the way I quoted those, BTW, but until they fix the way nested quotes are now destroyed by the Quote function...... )

Anyway - it doesn't sound like the mower has an earth fault which would trip an RCD as it's clearly not being supplied by the OP's, so it is looking like an upstream fault triggered by the mower motor.

 

[jj4091]

Try running the mower on an extension lead plugged into your ring main.

 

[DaveHerns]

Maybe the neighbour is already doing that ......

 

[ban-all-sheds]

Apparently not.

Is it every time? When your RCD trips put, does his lawnmower immediately stop, or does it not affect him?

No, he's fine and just carries on mowing