Earth cable/10mm2

[notb665]

I want to make sure the electrician has done his job properly.

I have lifted a floorboard to fix a leak in some plumbing. There is some bonded 10mm2 cable.

I would like to make sure this goes back to the block on the consumer unit. How do I do this please?

I have a multimeter, if this helps.

 

[who took my fluke?]

what is the cable bonded to and where is the cable (bathroom, bedroom?). is the cable bonded between pipes? can you give more details maybe a pic.

the simplest way though to see if the 10mm cable has been terminated back at the consumer unit is to open the consumer unit and look!! be careful though as there will be live conductors in the CU. im guessing, but have you have had a new shower installed?

 

[notb665]

Thanks for your response.

We have actually had a whole new bathroom installed upstairs (previously I had to go downstairs in the middle of the night!). The kitchen moved round the corner into what was the garden and a new bedroom upstairs put on.

There are two 10mm2 earth cables going into the consumer unit, (which is in the middle of the house) one for the gas meter which used to be over one side of the house and one for the bathroom which was over the other side.

I watched him coil up the one to the gas meter and leave it under the floorboards upstairs, as the gas meter was moved to the outside wall near the downstairs bathroom. The new-position gas meter was then bonded along with the bathroom downstairs (which always should have gone back to the consumer unit).

I just wondered if there was some kind of test I could do to make sure the cable routes back to the consumer unit, and that it hasn't been left loose anywhere. Maybe this isn't possible and it is just a mechanical/visual test.

 

[notb665]

I opened up the back of a socket and tested for continuity between an earth off the ring circuit and a clamp connector on the pipe.

It buzzed!

So hopefully all is OK.

 

[ban-all-sheds]

Equipotential bonding doesn't have to go back to the CU. (It's also not supposed to be under the floor, but we'll gloss over that, as that's where mine is - bedammed if I'll have that stuff on show...)

I opened up the back of a socket and tested for continuity between an earth off the ring circuit and a clamp connector on the pipe.

It buzzed!

So hopefully all is OK.

Hopfully. But hoping is not a good strategy. Check the specs of the meter - see what the maximum resistance is that it will buzz at....

Also, that test doesn't prove that the extraneous-conductive-parts in your bathroom are adequately bonded to the cpcs of the lighting circuit, the shower circuit, etc.

 

[kai]

Official way is to switch off at mains, place temporary link between red and earth conductor at fusebox, and measure the continuity resistance at the socket end to see if it's OK, (i.e. "taking the readings of R1+R2"), if you get a low resistance reading in the order of Half an Ohm or less, on a standard ring, on a TNCS system, it should be fine.

 

[notb665]

Thank you Kai, I appreciate that.

 

[jenki]

Equipotential bonding doesn't have to go back to the CU. (It's also not supposed to be under the floor, but we'll gloss over that, as that's where mine is - bedammed if I'll have that stuff on show...)

B.A.S Question for you - How do you bond a radiator on a wall to the Hot and cold on the other side of the room, without going under the floor? Iknow this is supplmentery bonding - so might have answered my own question but even main Equipotential bonding must go under floors at some point

 

[ban-all-sheds]

I meant that the clamps aren't supposed to be under the floor...

 

[jenki]

I meant that the clamps aren't supposed to be under the floor...

Now with that I agree - You tile your bathroom, shiny new towel radiator and then have to stick on a c**py clamp.

 

[plugwash]

you can get around that one by using soldered joints to the pipes

i get the feeling many sparks dislike soldering though

 

[jenki]

you can get around that one by using soldered joints to the pipes

i get the feeling many sparks dislike soldering though

I presume you still need the Metal identification tab though??

Also - might be a silly question (in case ), but do you just use a powerful soldering iron for this or one of the smaller gas flames?