Earth bonding for LPG hob pipework

[HarryM]

I am having an LPG gas hob fitted in my kitchen, and want to make sure all the electrics are in place. The installation consists of just over 3m copper 10mm pipe from the hob to the propane gas bottles outside the kitchen, and I presume the pipe should be bonded to earth.

The igniters will be fed from a fused switched outlet which is on a spur from the main consumer unit. Is it sufficient to earth the copper pipe to the earth on this spur or do I have to run a seperate earth back to the consumer unit earth?

(The house has no ring mains, just radial circuits individually fused. There is a RCD between the consumer unit and the incoming mains, and a physical earth spike connected to the consumer unit earth - type TT in the FAQ.)

 

[Spark123]

You will need to have run in a main equipotential bond from where the pipework enters the building (preferably within 600mm) back to the main earth terminal. As the system is TT, the bond will likely need to be done in 6mm² cable (providing the earth fault loop impedance is greater than 1ohm.) As this is outside the scope of what I would consider DIY and is in a kitchen, hence also notifiable under part p, my best advise to you is to contact a suitably qualified electrician.

 

[baldelectrician]

the bond will be ok in 6mm, but I would use 10mm- the REC may come along in a little while (just after you finish decorating) and upgrade supply to PME.

I always put in Main Bonds in 10mm.

Belt and braces

(i know the regs are not retrospective)

 

[HarryM]

Thanks,

Now I know what's needed I'll make provision for the cable, and get an electician to connect up.

Harry

 

[HarryM]

I have run in a length of 10mm earthing cable ready for an electrician to connect up to the consumer unit. I had intended to fit and connect up the earth clamp myself as it will be difficult to install after the last kitchen unit is in place. There is enough access for the electrician to inspect it to make sure it's OK.

However I can't find an earth clamp that fits 10mm dia copper tubing - they all seem to start at 12mm. Is there such a thing? Or how else do pros bond to 10mm tube?

 

[ban-all-sheds]

the bond will be ok in 6mm, but I would use 10mm- the REC may come along in a little while (just after you finish decorating) and upgrade supply to PME.

Regs or no, don't some DNOs ask for 16mm² main bonding? I thought I read somewhere that some do.

 

[HarryM]

Considering my question, perhaps it's more complicated.

If I fit the earth clamp near the entry point, I preferably need to do this myself, in which case I need a clamp that fits 10mm tubing.

However although the electrician will be able to inspect it, the clamp will normally be hidden by a "filler" at the end of the row of kitchen units. Is this OK?

If the clamp has to be visible then the only place for it is near the hob which is nearly 2 metres of tubing from the entry point.

If this 2m is OK, I will install the units and worktop and leave a length of earth cable unconnected. The sparks can fit a clamp after the Corgi-approved guy has finished the LPG installation.

Any advice appreciated.

 

[HarryM]

(bump)

Anyone?

If I leave it to a sparks to connect the earth clamp it will be almost 2m from the point of entry of the LPG pipe. Is this OK?

Or if the clamp has to be closer to the point of entry (which I will have to do myself before fitting the last kitchen unit) how can I connect to 10mm copper tubing? And is it OK for the clamp not to be visible?