Gas pipe & Consumer Unit Question

[Toby]

As I understand it, a gas pipe, where installation pipes are not separated by electrical insulating material, they shall be spaced as follows:

a) at least 150 mm away from electricity meters and associated excess current controls, electrical switches or sockets, distribution boards or consumer units; b) at least 25 mm away from electricity supply and distribution cables.

I have a gas pipe installed against a wall, and I would like to install the consumer unit on this same wall by placing battens on the wall, and a piece of wood across, so the pipes are then running behind the CU.

I assume MDF doesn't count as electrical insulating material (or does it?) so can I simply encase the gas pipe in some trunking (so it can be installed on an already connected pipe!) like this

is there something better to mount to the battens first, then screw the MDF to?

I am trying to avoid having to bring the CU out from the wall by 150mm you see!

Thanks :-)

[dom]

If you have to do this, using platerboard or cementboard in a sandwich with ply/chipboard may be better, as these first two materials are properly fireproof.

[Toby]

I don't think it is to do with being fireproof, as I have read that PVC coated copper pipe meets the requirements!

I am not really sure the reason for having this if this really is the case!

[BigWallop]

If you have a blow back from an electrical appliance, the resultant spark can actually blow a hole in nearby or touching copper pipe. Like striking a welder on the surface of any metal object, the copper will melt at that spot where it is touched.

A workshop in the same estate as ours had a short across something or other. It blew back along the earth conductors and found a loose earthing strap on the mains water pipe. The loose strap arced over and blew a hole in the pipe. The water jet was strong enough to spray across all the office desks and it destroyed a lot of the paperwork and a printer.

That's why the spacing is needed, and all earth bonding to made as tight as is possible to all pipework.

[Toby]

Thanks for the explanation!

So, if the CU is mounted on a MDF board, and the copper pipe is incased in PVC trunking, I assume this will prevent this from happening!?!

[BigWallop]

That should be fine, but what thickness of MDF are you using? MDF will soften in moist atmospheres, so make sure the MDF is strong enough to hold the weight of the CU and all the bits and bobs that you're putting in it.

For a secure fixing on the CU, I find using a piece of flooring grade chipboard works perfectly. Consumer Units are heavier than you think, so need something robust to keep them on the wall. Flooring board is just what the doctor ordered for this type job.

[Toby]

Fair comment, I have a load of 18mm MDF off-cuts spare, so I was planning on using a piece of this, as I have it already.

The meter board (below where the CU is going) appears to be 18mm chipboard, so I think, as per your suggestion, I will match this, worth getting the WBP stuff while I am at it?

Toby...

[BigWallop]

The MDF can soften quite a bit over time, and it's made up of laminated sheets to make it thicker, which can often break apart, so it is not something I'd use unless in an emergency or for a temporary situation.

Anyway, jobs done. Have fun with it. :-)

[Toby]

Really, I thought it was made in one piece from wood fibers all compressed together? You are not thinking of Ply are you?

[BigWallop]

No. Honestly. MDF is made from thin layers of compressed fibres. It is not made in all thickness' in the factory. Only made in thin sheets like cardboard. If they want it any thicker, they glue another sheet on top and squeeze it hard. Honest Injun. Cross my heart, and may the maker strike me down with a li.....................

Couldn't resist that bit at the end. LOL :-)