Recom'd - Heat sheilded 6 core cable (for boiler timer)

[PingCrosby]

Hi

I have a boiler with a non-working mechanical timer that I intend to replace with a more controllable / working modern electronic one.

Currently the timer is attached to the boiler itself, so I am considering putting the new timer in a more accessible location - by just extending the cable from the existing boiler control block.

Internally there are 6 wires - L, N, switched CH (on/off) and switched HW (on/off) - I am looking for a 6 core cable that is heat shielded. I have found some by tower electrics BUT sadly they only do it in 50m reels. I only need ~3metres (if that)

Does anybody know of any manufactures that supply this in short cable runs - alternatively does anybody have any alternative suggestions??

Thanks

 

[gas4you]

A local electrical outlet will usually supply cable cut to length, or you could use 2 3 core cables.

 

[PingCrosby]

Dave,

Do i need to use heat sheilded cable or will ordinary T&E / 3 core cable do the trick.

The wires currently in the boiler are just thin unshielded cables that go to the timer from an internal choc-blok. My intention is to wire directly into this choc-blok (removing the original unused wires) and use the existing entry hole & cable path (where the mains feed enters the boiler) fixing the timer elsewhere.

The wiring will be clipped to the wall following the current input feed path as much as possible before passing through a wall to my porch (boiler is in garage) where i plan on fixing the timer.

As the ampage is so low inside the boiler I am thinking that i could probably get away with flex

Any comments?

 

[D_Hailsham]

B&Q sell 5-core plus earth cable in 5 metre lengths. One of the Bradford stores should have it.

 

[gas4you]

Any cable entering the boiler needs to be heat resistant to 85C.

This looks like normal flex, not the butyl cable you can also buy.

It only needs to be 0.75mm cable/flex for boiler use.

 

[PingCrosby]

been looking on B&Q website and did not see that

 

[PingCrosby]

Any cable entering the boiler needs to be heat resistant to 85C.

This looks like normal flex, not the butyl cable you can also buy.

It only needs to be 0.75mm cable/flex for boiler use.

Are you saying that all UPVC cable is heat resistant to 85c by default and I do not need to worry about special heat resistant cabling?

 

[gas4you]

No, you need to specify heat resistant when buying, but it doesn't have to be the awful thick butyl type.

That is mainly for immersions and storage heaters.

 

[PingCrosby]

Ahh thanks for clearing that up.

Am i allowed to use flex though? as the wiring guidlines for the controller suggest fixed wiring - which i was under the impression was/is solid core.

Ideally i want to use 2x3core .75mm flex as this gives me the best flexibilty and I will be easier to use the existing choc-blok inside the boiler.

As its flex - the earthc wire will be just as as well shielded and have the same cross section as the other wires so I presume i can use this instead of buying 3 core + earth? (saves me haveing to cut the extraneous earth)

 

[gas4you]

Technically you should always use 3 core + earth, so as not to use the earth wire, even in flex.

Some however do use this, but add a brown sleeve to the earth to identify it as a live to other users in the future.

 

[kevindgas]

Some however do use this, but add a brown sleeve to the earth to identify it as a live to other users in the future.

and those that do should be f***ed with a hot blunt instrument!!

all cable should be earthed use 2 cables if you cant get 6 core and use earth as earth in all cables