Boiler fed off lighting circuit

[kingeri]

I usually run them on a 1.5mm with 6a breaker, in most cases could actually use 1mm though.

 

[richy3333]

Had it myself this week too, on a CU renewal. Old Wylex, rewirable and the plumber had stuck the 2.5 into the 5A fuse of the lighting circuit as there were no other ways avaialble. Just moved it on to its own, appropiate RCBO when putting the new board in.

 

[Geoffsd]

I am puzzled by the idea that a 'lighting circuit' should feed nothing but lights - oh, and fans - and heat/smoke alarms - and door bells.

Should a 'socket circuit' feed nothing but sockets?

Aren't all circuits just circuits?
Because the label on the CU says 'lights' does not mean you cannot add 'and boiler' or whatever.

Can correctly designed circuits not supply anything you want?

 

[Guest55]

add to geoffs list , shaver sockets , tv boosters in the attic.
in fact any load under 2amp will happily run off a lighting circuit with few problems.

 

[kingeri]

I am puzzled by the idea that a 'lighting circuit' should feed nothing but lights - oh, and fans - and heat/smoke alarms - and door bells.

Should a 'socket circuit' feed nothing but sockets?

Aren't all circuits just circuits?
Because the label on the CU says 'lights' does not mean you cannot add 'and boiler' or whatever.

Can correctly designed circuits not supply anything you want?

That's just the point, do these people who charge in and connect a boiler to a lighting circuit consider loading, diversity etc.? Probably not, they just bang it in.

 

[Octopus]

That's just the point, do these people who charge in and connect a boiler to a lighting circuit consider loading, diversity etc.? Probably not, they just bang it in.

and usually its a spur off a spur on the ring!

 

[Farmelectrics]

what power does a combi boiler usually use

 

[kingeri]

what power does a combi boiler usually use

Barely any TBH

 

[Welchyboy]

add to geoffs list , shaver sockets , tv boosters in the attic.
in fact any load under 2amp will happily run off a lighting circuit with few problems.

Old kitchen clocks too!!

 

[Farmelectrics]

whats barely nothing lol 1a 2a ??????

 

[MDJ]

it is the load of the main pump in there, I expect if differs from combi to combi, we have all agreed we wouldn't do it off the lights if a new build, so it is a case of existing wiring available to make it work, personally I do think I would avoid the lighting circuit, but as mentioned in my first post it is not anything other than unusual to do it this way, actually perhaps not so unusual as some of you guys have said you have seen it or done it this way, if there is a 6 amp circuit in a house and a few pendants off it, in reality it isn't a big issue adding off the lights really, just a crappy way to do it, standards and all that haha.

 

[Fin170]

Recently found a workshop connected to a lighting circuit, as usual, never melted. Will start using 3amp MCBs just in case :lol:

Just moved it on to its own, appropiate RCBO when putting the new board in.

Plumber buried the cable less than 50mm into the wall?!

 

[victorr]

The manufacturer of the boiler is required to state the electrical supply requirements of the boiler. These will comply with the current IEE regulations. these will state that supply will be through a suitable switch having a minimum separation between poles of 3mm a fuse of 3amps and that the supply be fully earthed. Many lighting circuits fitted in houses in this country still do not carry an earth wire! despite 1971 regulations. Central Heating boilers should have their own independant supply from an MCB/FUSE in the consumer unit with a suitable rating.

 

[Geoffsd]

Central Heating boilers should have their own independant supply from an MCB/FUSE in the consumer unit with a suitable rating.

That's not really true and definitely not always practicable.

The mcb/fuse in the cu is there to protect the cable and will not be double pole.
As long as a (usually) 3A fuse and the required isolation switch is fitted before the boiler it will comply.

Any correctly designed circuit will be satisfactory.

 

[growler]

why does everyone seem to run a 2.5mm on a 16amp ?