Combi Boiler - Fuse box install

[ickleric]

Hi,

I have a Baxi combi boiler which had installed about 3 years ago. The guy told me i needed to put a fuse box next to the boiler for it to run off. In order for him to get it working he just wired the boiler to a plug, which just runs off a normal socket. I am finally getting round to putting a fuse box in, but wanted some advise. Does it need to have its own connection running off the main fuse/circuit breaker? I do have a fuse box outside my bathroom which was used for a electric heater, but that isn't used anymore, would this surfice? I could re-route it if that is suitable.

any advise or comments?

 

[Taylortwocities]

I guess you mean a switched fused connection unit (FCU), not really a fusebox?

If so it should be located close to the boiler, not somewhere else, so that someone maintaining the boiler knows where the switch is.

Perhps you can extend the socket where the boiler plugs in and add an FCU?? What's the problem with leaving it as it is??

 

[ickleric]

yeah your right a FCU is what i'm talking about.

Basically the boiler is in a bedroom, which is going to be my babys room which is due anytime. So i'm in the process of decorating and would like it all nice and safe.

Yeah if i used the existing FCU i would put the box next to the boiler, just extend the cable. Would that be good enough?

I've heard if the power cable is too thick/big it might blow the boiler, is this true? If so what sort of cable should i use?

 

[ban-all-sheds]

would like it all nice and safe.

I'm sure it'll be a room-sealed boiler, but please do check.

And install a CO alarm too.

Yeah if i used the existing FCU i would put the box next to the boiler, just extend the cable. Would that be good enough?

It depends on how you extend the cable - basically unless you use crimps then the junction needs to remain accessible.

Also, if you're moving an accessory you need to ensure that doing so doesn't remove any concealed cable zones - see these:

• http://www.voltimum.co.uk/files/gb/attachments/niu/l/attachments/c5-43.pdf
• http://web.archive.org/web/20061110111450/http://www.niceic.org.uk/downloads/concealedcables.pdf
• IEE article
• IEE Article on 17th Edition requirements for concealed cables.

I've heard if the power cable is too thick/big it might blow the boiler, is this true?

No.

 

[ickleric]

yes its a room-sealed boiler, and yes were getting some CO alarms.

Would it be easier if i ran the FCU off a socket in the same room? Would this be good enough?

 

[ban-all-sheds]

You could do that, assuming the socket isn't itself a spur from a ring final.

You still need to ensure that you follow the rules for concealed cables.

 

[ickleric]

so i could run a FCU but only if its off the main ring?

i'll probably run the cables under the floorboards so shouldn't have a problem, if i conceal them i will make sure i follow the guidelines.

Cheers

 

[2face]

yes you can leave it plugged in it is safe and sound.

its no safer fitted to a fuse spur but looks better.

 

[ickleric]

so if i run a fuse spur of my ring main, what size cable shall i use from the socket/main ring to the FCU? Also what size cable to run from the FCU to the boiler?

 

[Taylortwocities]

so if i run a fuse spur of my ring main, what size cable shall i use from the socket/main ring to the FCU??

The same size as the cable that is used to wire the ring final.
Usually 2.5mm.

Also what size cable to run from the FCU to the boiler

Depends on what fuse is required for your boiler. Thats the fuse size that goes in the FCU and will determine the cable size. Usually its a 3A fuse and you could use 1.0mm for that. Why not use the wire thats already there, cut off the plug and re-terminate the cable into the FCU.