Heating programmer on its own CB in the consumer unit

[wojtek]

Hi everyone,

Recently we had our wiring replaced for the heating system.
I am challenging the guys that did this and said:
"The heating programmer has been put on its own MCB in the board - so it does not require its own Fused outlet"

Before we had a 3A fused spur to which the old programmer was connected to.
Now we have a dedicated 6A circuit breaker in the board linked to a heating programmer.
Is this OK? or even though it is a dedicated CB do we have to have this 3A fused outlet?

Many thanks.

 

[Steve]

Not sure on the regs for heating controls, but the controller itself is probably capable of handling a few hundred watts, so could be fine with 6a protection.

BUT many controllers specify (and it might be in the regs) local double pole isolation. And if the boiler is remote from the controller, it may also require local DP isolation.

 

[Taylortwocities]

The 6A MCB will be the nominal current limit for the whole heating system.

Better check the boiler and programmer installation instructions. They may well specify a 3amp fuse.

In any case, I believe that it is a requirement for central heating systems is for a double pole isolator. In which case the contact breaker in the consumer unit does not comply.

If the above are correct, and I think they are, then should fit a double pole FCU with a 3A fuse.

EDIT: I just check out Glo-Worm's site. They specify

"Connection of the whole electrical system of the boiler, including any
heating controls, to the electrical supply must be through one common isolator and must be fused to 3 Amps maximum."

 

[AndyPRK]

I wouldn't be massivly worried, but I'm sure all the valves and timers say it should be on a 3 amp fuse.

And as said DP should be used