Was asked by a work colleague to look at some alterations to a bathroom he's having done at home as he's confused by the different things local sparks are telling him. I've answered most of his queries but as I'm not involved in domestic work I need info on a couple of things. I'm not doing the work (Part P etc etc ) but want to stop him getting ripped off.

No new circuits are being installed just rerouted/repositioned for new layout etc.

Exsisting installtion supplied by a TT system to a dual 30mA RCD CU. The existing bonding is only 6mm to gas/water & main earth to the external rod is 10mm. Main & gas easy to upgrade if required to be upgraded to 16mm & 10mm respectively. Water will require a lot more work as it's on opposite side of house to the CU &.

Is it nessesary to upgrade the earthing? There's been a number of posts about upgrading PME etc if bonding is only 6mm & that, providing it's in good condition it is acceptable to remain in 6mm. As it's a TT I wasn't sure whether it's ok to leave the 6mm as it is if in good condition.

It has been suggested that the new earth to the water would be run around the outside of the house in plastic conduit, as it's an old stone house my colleague dosn't like that idea for obvious reasons. I've suggested another route to him which would involve the cable being run partly inside under the floor etc with the final bit being clipped externaly to the wall before entering the building again. Is it required to be enclosed when it runs outside?

I've not tested the EFLI but provided it's <200 Ohms all should be ok?

As there are RCD's on the whole installation & provided the main bonds are in place there is no requirement to supplemtary bond the new bathroom provided ?

Thanks in advance for your input.

10mm2 main earthing conductor and 6.0mm2 bonding is perfectly compliant with BS 7671, just leave it alone

Oh, and tell your mate not to hire the spark who told him it needs changing -

OMS

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Failure is always an option

If it's a TT system 6.00 mm is usually quite ok for the main earth to the rod and also for the gas and water bonding. I usually use 10 mm though just for it's better durability, --- less likely to get damaged than 6.00 mm,

Dave.

Dave

"less likely to get damaged than 6.00 mm,"

could you please expand on this statement?

I just think that 10.00mm, by means of it's larger size is more robust than 6.00mm so is less likely to get pulled out of clamps etc. than 6.00mm,

Dave.

Yes, but 6mm is more robust than 2.5 mm

For the main earth on TT I always use 10mm in conduit to the rod even though I carry 2.5mm on the van for bonding back boxes and accessories, but that's just me, total anorak going way over the requirements Table 54.1 page 159, mind you I don't carry 6mm any more though I do have some 4mm.

Andy

Yes, but how do you protect against corrosion?

Keep it dry?

Denso

Stu

PVC insulated cable in plastic conduit should not be subject to corrosion should it?

Andy

I find putting a blob of vasalene on the end of my rod keeps it in fine condition!

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John Peckham

http://www.astutetechnicalservices.co.uk/

I don't have any of that on the van, I have moved onto plumbers Rothenburger silicone lubricant.

Andy

Do you still get the small pots of vaseline with pyro?

Just wash it occasionally to prevent the Blue Stilton!

Regards

Quality Jaymack,thats my laugh for this morning

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Regards

Dave(not Cockburn)

While we are on the subject of lubricants, I am also looking at the avatar of dg66.

Some years ago whilst looking at houses for sale I visited one with my wife, I could tell she did not like it. However my wife was making polite conversation and enquired if the carpets were included in the sale price of the house. Oh!, no replied the lady of the house it is really good quality and Scotchgard, when my husband repairs his motorbike in the hall (the house has a garage) you can wipe the oil off the carpet quite easily! So we would have to charge extra for the carpets.

Andy

Really Mr Peckham - keep remarks like that to yourself!

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Regards,
Ebee (M I S P N)

Knotted cables cause Lumpy Lektrik

2.5mm in conduit fine with a bit of silicone. A bit more sticky than vasalene but i don't carry that sort of stuff on the van???????

For information and the avoidance of doubt I was referring to covering the clamp and termination at the end of my earth rod with vasaline.

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John Peckham

http://www.astutetechnicalservices.co.uk/

If you are really fussy you could surround the clamp with magic gel http://www.toolstation.com/shop/p54839 I can say I have never done it

Andy