spur or own elec supply to boiler

[desrob]

can anyone clear this matter up for me,i was told of an electrician friend that all heating systems should have there own independent supply from consumer unit,i have and i'm sure many others have got the elec supply from a spur or even in some case put a 3 point plug 3amp fuse and away you go ,this is even in some mi i've came across.i can understand the thinking of it's own circuit,but how often is it put into practice,not a lot i think,could be wrong please enlighten me,

[GQuigley67]

I would think its fine to use a spur, but then if an electrician is working on the sockets and he's turned the sockets off at the consumer unit then household doenst have any heating, maybe that's the case.

[desrob]

yes .thats the logic,but is it necessary

[quality]

No it isn`t, it is good practice to have the heating on its own circuit but it is not a regulation must have, a switch fused spur is fine

[Mick Helpful]

This more of a health & safety issue than Mode of connection. A boiler should be disconected from the supply when servicing and not be capable of being switched on inadvertently. As an electrical appliance, a gas fired boiler is a low current item so the final sub-circuit is not relevant. For discrimination purposes its best to have a single final subcircuit with a 16A mcb feeding a 20A switch or BS546 15A socket outlet. The 15A socket outlet provides the best isolation (far >6mm} and being a round pin plug it can't be inadvertently connected to a BS1363 13A socket-outlet. With its own sub-circuit any short circuit fault elsewhere doesn't affect the boiler. However there is nothing to prevent a boiler being fed via a fused connection unit off a ring main or radial sub circuit.

If an RCD is fitted to the installation, which it should be, any earth leakage fault will cause loss of supply. This will occur regardless of in which circuit the earth leakage fault occurs.

[James.C]

This is quite a confusing issue but basically it is down to interpretation, there are no rights and wrongs, I use a seperate circuit to a switched fused spur and I hasten to add not on the RCD side of the CU, the reason for this is that nuisance tripping does occur which means you could lose the heating and particularly in this cold weather we are experiencing could result in burst popes etc, the same principle is applied to freezers in that an RCD trips whilst you are away and you have lost everything that was in there, so it is for practical and economical reasons these circuits are usually on the non RCD side which is why High Integrity Consumer Units are now on the market.

[Reg Man]

If It is not RCD protected, Have you not got to use a permenent wired fused box? ie: should not use 3pin plug, because that could then be used for other household appliances if it were to be removed.

[James.C]

If It is not RCD protected, Have you not got to use a permenent wired fused box? ie: should not use 3pin plug, because that could then be used for other household appliances if it were to be removed.

Thanks for getting back, you are absolutely right, which is why I said it's own supply to a 13amp switched fused spur (not socket) obviously with the fuse down rated but because this is hard wired no one else can access the spur without the use of tools so it is perfectly acceptable and within regulation.

The reason for the switched spur is for local isolation where this can be done by the flick of a switch and or removing the fuse, saves going back to the Consumer Unit

hope this is helpful and please feel to contact if you require other electrical info

[Mick Helpful]

Reg Man wrote: ie: should not use 3pin plug, because that could then be used for other household appliances if it were to be removed.

Still using 5A and 15A plugs for everything? All appliances by law these days come with a 13A plug fitted You
can get 5A and 15A plugs fitted with a fuse, they're not cheap tho'

[quality]

I would like to clear the current view if I could

Fixed equipment i.e boilers requires fixed wiring and had done since 1992 that is that sorted

new circuits as of now or since 2008 have to be RCD protected but that does not mean that the central heating has to have its own circuit. It can be supplied by a ring main which has rcd protection and via a switched fused connection unit SFCU
it only has to be on its own circuit if its new build after 2008 of if rewiring / renovating

The local building inspector will advise the same

[Reg Man]

Still using 5A and 15A plugs for everything? All appliances by law these days come with a 13A plug fitted You
can get 5A and 15A plugs fitted with a fuse, they're not cheap tho'

Only if there is no RCD protecting the circuit. There is benefit to using 3pin plugs on an unswitched shuttered socket. Isolation of the boiler when carrying out work is absolute because you have to remove the plug. On a fused spur how many just flip the switch?

[James.C]

OK, without trying to get into a heated argument, (RCD's in the application in question) The regulations can be quite confusing, they are not a legal requirement, only guidelines for recommendation. so I would like to clarify something, which is, that whilst it is preferable for all circuits to be protected by an RCD it is not written in stone that they have to be, you have to consider the practical applications of the installation, so in my view, the exemptions to this are Freezers, Smoke Alarms & Boilers because all could be adversly effected by being on an RCD circuit, which again is why there are now High Integrity Consumer Units on the market to allow for this. however, having said that, there is nothing wrong with connecting to an RCD if so desired, you just have to accept the consequences of the end result, i.e smoke alarms not going off in the event of a fire were the batteries to fail, loss of food stuff if the freezer went off whilst away due to the fault of another circuit or burst pipes because the heating went off for the same reason. something to think about!

If I were to do the job for DESROB who asked the question on this, then I would suggest creating a new circuit, supplied by a non RCD protected CB as they are now known (Formerly MCB) of the appropriate size which is dictated by the boiler and cable size and then connect to a local 13amp fused spur, again with the appropriate fuse fitted.