Posting a message to the forum will remove the above advertisement
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. Checkout our Plumbers Insurance area - heavily discounted Public Liability Insurance and Van Insurance specifically designed for plumbers.

Discuss Dedicated circuit for Boiler Power in the Central Heating Forum area at

  1. fixitflav

    fixitflav Member

    3kW wouldn't keep the house very warm
    • Funny Funny x 1
  2. Ric2013

    Ric2013 Plumber Top Contributor!!

    Personally, I would like to see the boiler on a dedicated RCBO, if it were a new installation in my own house.

    I have lived in places where trivial faults on a heating system (normally a room stat, weirdly) have tended to trip the RCD, and it nice to be able to pinpoint the cause more easily. That said, where I live at present, the fused spur is off the ring main and it has not caused any trouble in the last two years and I have no intention of having a new circuit installed at the present moment.

    Thinking to the last time I read the electrical regulations (not that I am an electrician), I think there was some point made about the advisability of designing a system to avoid nuisance tripping, but I think this was to be interpreted by the designer of the installation. As you are not installing an entire new electrical system, I doubt you would be expected to have a dedicated circuit for a replacement gas boiler, but I expect some people will disagree: if there's one thing I have learnt about electricians, it is that no two will agree on everything.
    • Agree Agree x 1
    • Funny Funny x 1
  3. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    How do you know the heatloss :D
    • Optimistic Optimistic x 1
  4. fixitflav

    fixitflav Member

    I don't, but I'd hazard a guess that if it's for a whole house the heat requirement is well above 3kW :)
  5. quality

    quality Plumber GSR

    I appreciate your logic and your quite right I would guess a whole house is above 3Kw. A jobwe did recently did surprise myself I had to double check my calcs.
    A barn conversion with heat pump in mind from the beginning. The total heat loss for 3 bed, 2 en-suite, lounge dinner, large kitchen etc. etc. was just 4.2 Kw. It cost a few quid and there was plenty of non standard work but shows things can be done very well when the money is there. Sorry to hijack the post
  6. Vee

    Vee Plumber GSR

    BS7671 314.1 Every installation shall be divided into circuits, as necessary, to:
    (i) avoid danger and minimise inconvenience in the event of a fault
    (ii) facilitate safe inspection, testing and maintenance.
    & (iv) reduce the possibility of unwanted tripping of RCD's due to excessive protective conductor (PE) currents not due to a fault
    BS7671 314.2 Separate circuits shall be provided for parts of the installation which need to be separately controlled, in such way that those circuits are not affected by the failure of other circuits, and due account shall be taken of the consequences of the operation of any single protective device.
    Interpretation of Best Practice within this is of course in the eye of the electrician.
    • Informative Informative x 1
  7. fixitflav

    fixitflav Member

    Are there systems out there with usual pump and rads, but electric boiler? I've never seen one, not that that proves anything. I'd have thought if you were going for electric you might as well have a heater in each room, or even storage heaters.
  8. Murdoch

    Murdoch Active Member

    And your point is?

    The above points are relevant to new designs and considerations for changes to existing installations.

    Swapping a boiler is neither of the above

    You are precisely the type of individual that goes out of their way to confuse un-suspecting clients and spend unnecessary money.

    A gas boiler does not need to be on a individual circuit..

    For all you know the OP may have any older fuseboard with a single upfront RCD .. so putting in another circuit would have absolutely no benefit to him.

    And new circuits fall under Part P of the building regs too.
    • Agree Agree x 1
    • Disagree Disagree x 1
  9. Chester

    Chester Member

    Yeah potterton gold is one. Heat only electric.
  10. Ric2013

    Ric2013 Plumber Top Contributor!!

    Yes, but surely the minute you touch an existing installation, you start to become responsible for it?

    If I have BS 3036 fuses and rubber cable in poor condition and then I replace my electric cooker with one of similar current draw to the existing one, I would not be changing an existing installation either, but can I legally do so? I know you can't do it the other way around (i.e. put a new circuit in to feed a piece of electrical equipment that is only running on Grandfathers' rights, and also in poor state), but can you do it this way round? My feeling is that, like running a new light fitting onto a circuit that would not pass an EICR, the answer is 'no'.

    Having said all that, I would agree that most electricians would probably not interpret the regulations to mean a new boiler MUST be on an independent circuit, as Vee has not denied.
    • Like Like x 1
  11. Murdoch

    Murdoch Active Member

    Not if all you are doing is disconnecting 1 accessory and connecting a new one.

    The OP's question was does a new gas boiler (in an existing installation) need to be on a dedicated circuit.

    The answer is no.

    What an designer / installer would do on a refurb/ rewire / new build is a completely different question all together
    • Agree Agree x 2
  12. Vee

    Vee Plumber GSR

    You conviently ignore the OP's question/reference of "Best Practice". I accept and did not contradict your minimum standard you wish to apply is legally acceptable. That does not make it the best way of dealing with it. Surely anyone is allowed to promote a better way of doing things in order to give customers a choice. Especially when they are informed,willing and wanting to pay for that.
    • Agree Agree x 1
  13. Murdoch

    Murdoch Active Member

    Best practice on existing installations is largely irrelevant unless it doesn't mean lifting boards, dropping ceiling and chasing walls
  14. Murdoch

    Murdoch Active Member

    I've covered this in my responses .... If the OP is happy to have boards lifted, walls chased, floors disturbed then its UP TO HIM

    But there is absolutely NO NEED in existing installations.

    Do you insist on zoning houses when you change a boiler?
    • Agree Agree x 1
  15. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Zoning is a building reg mate so it's needed
    • Funny Funny x 1
Similar Threads - Dedicated circuit Boiler Forum Date
What is the correct orientation of a tee in a flow return circuit? Central Heating Forum Nov 4, 2018
Gurgling from primary circuit, Y plan system Plumbing Forum Nov 1, 2018