What cabling does a normal oil fired boiler use?

[Steve T]

Hi all

Mate of mine is getting a new utility room fitted, the kitchen fitting company have brought in their electricians for first fix and to be fair they've done a good job, neat chasing, capping used, all cables in zones etc. They've also had to chase in the boiler feed which was in surface trunking originally, and the boiler was only supplied by a twin and earth, which is all it needs, and they've just put a new twin and earth cable in, so all works fine.

However our concern is when the boiler inevitably needs replacing (around 15 years old probably) I'm guessing it will need more than just a switched live and neutral. The current system is an S plan, however it's not standard, they've used a Honeywell Smartfit system which if you're not familiar uses a sort of electronic central hub and all the components (motorised valves, cylinder stat etc.) just plug into it via extra low voltage data cables. So as the system is obsolete, if anything fails, unless we can source spares on ebay, the whole system will need to be replaced with a normal S plan. As a point to note the boiler is remote to the rest of the system, it's all in an attic space so easy to rewire.

So what wiring would a new oil boiler need on a standard S plan??

Our plan is to ask the electricians to put in another cable(s) for future proofing to the boiler connection point before everything is plastered over.

Thanks!

 

[DefyG]

If they are going 'smart', and you already have LN&E at the boiler, wireless switching devices will suffice.

 

[Lucien Nunes]

As an insurance I would run in an additional 3C+E cable to allow for control in both directions and a spare core.

 

[brianmoooore]

Applies more to gas boilers than oil, but, with heat exchangers being made of the minimum amount of metal possible, some boilers require that the pump runs on for a short while after the boiler switches off to avoid the exchanger overheating and boiling the water left in it. Unusual for an oil boiler, but some do exist.
This requires a permanent live to be fed to the boiler, as well as the normal switched live, and, if the circulating pump is remote from the boiler, a wire back from the boiler to the pump will be needed.

 

[MJPD29]

As above its always helpful to have extra cores for future use but unless specifically directed it's unlikely they will bring any extra cores to the boiler as they aren't currently required.

 

[Steve T]

Cheers for the help guys, we'll ask them to run in an additional 3 core and earth now that the wall is chased, in case any new boilers in the future require it, but
I understand they had no reason to do so initially