Boiler cable - proximity to gas/HW/CH pipes?

[Lobster]

I'm preparing for a new boiler installation in a new kitchen. Space is tight, and I am running all 5 pipes to/from the boiler at ceiling level in a narrow gap (about 30mm?) between the top of the upper wall cupboards and the ceiling, which will be boxed in.

Unfortunately for various reasons the wiring has gone slightly awry in that at a late stage I need to add a new 3C&E (mains) cable to provide for a room stat, and this really needs to be run in the same gap - which is now full of pipes! How close can the cable be regs-wise to the pipes (presuambly it doesn't matter which, as in gas/water/CH?). Will have to pass inspection later on.

If I haven't got room then I know I could go wireless, but would rather not have to.

Thanks David

[VisionSet]

25mm for gas, I don't know of a reg for water.

-- Mike W

[John Stumbles]

/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.

(My /emphasis/).

[Ed Sirett]

You must allow for the heat from the heating pipes to affect the rating of the cable. So if you can avoid the hottest pipe(s) you would do well.

[Andy Hall]

So no suggestion of sensitivity of cables to heat?

I'm not sure that I've seen anything specific on this in BS7671 either.

[Lobster]

Great, thanks all. So - no reason why it can't butt up against the cold water pipe feeding the boiler then?

(What would consitute the "electrical insulating material" regs-wise, which John mentioned?)

Thanks David

[John Stumbles]

Well you wouldn't expect that in BS6891 since if gas pipes are getting hot their effect on nearby electrics are probably some way down your list of concerns:-)

[Andrew Gabriel]

Such as the cable sheath?

Depends on the cable. 70C max for standard T&E. Since boilers can typically go up to 85C, you will need to use higher temperature cable in this circumstance.

[Roger]

The message from John Stumbles contains these words:

You may have me worried. Since fitting a wider consumer unit my main cold water feed (22mm copper) is only about 1.75" from the closest corner. Does the plastic consumer unit box satisfy the bit about "separated by electrical insulating material" or do I have to reroute the cold water? It is more than 25 mm away from the nearest wire and as it's cold water there is no question about excess heat.

[thankyousam]

I have 2 ring circuit cables running within the 150mm channel below the ceiling. Is it acceptable to run the cables behind dry lining/plasterboard and have the pipes mounted on top of the plasterboard? Would the cables need further protection? The cables would be running at 90degrees (as in angle, not temperature ;) ) to the pipes only for the width of the pipes (~100mm)

[Andy Wade]

BS 6891 is only concerned with gas installation pipes, not water.