Is it ok to share an Immersion feed with main heating controls?

[LeeJC]

Hi All,

Currently my heating controls are in the garage with the boiler, after fitting a hive last week I was considering moving them into the airing cupboard and taking the following approach, has anyone got any glaring gotcha's I've perhaps not considered please.

System is Y Plan
Currently heating controls sit on a 3 Amp spur (need to check the fuse is actually 3 Amps) from the downstairs ring final.
Cables running from garage to airing cupboard are 4 Core + E and 2 Core + E. The wiring was a b*ggers muddle but I've sorted that out so the controller/valve/stat are all working how they should.

Vented Tank has an immersion heater, which is currently not in use (lets assume it's faulty)
Unvented system is due to be fitted in the coming weeks, not sure I want to fit an immersion at all to it, any compelling arguments as to why I would?

So the question.

Can I extend the 2.5 mm Radial that's being used for the Immersion through a 3 Amp fused spur in the airing cupboard to power the controller/pump/boiler/valve and stat?
Is it acceptable practise to share a power feed like this? The board currently has an 15 Amp cartridge protecting the feed for the immersion, this is going to be replaced by an RCBO at some point once OVO have fitted a double pole isolator.

If this is better placed in the Electrics section can a moderator move it please.

Cheers
Lee

 

[LeeJC]

Replying to my own thread to prove I’ve got friends
Photo of fuseboard included


Immersion feed is number 2


Cheers
Lee

 

[Madrab]

I would say you would need to be careful, the 3Kw immersion heater would be rated @ ~13A. You would probably get away with it as the boiler and it's controls wouldn't be pulling a lot of current but never the less. Any issue with the immersion heater could cause a surge in the circuit. If the FCU for the heating controls was 3A then should it be ok but couldn't be sure.

Best to check in the leccy bods forum I would suggest.

 

[Mottie]

Dunno if it’s right or wrong but my heating controls and immersion share the same feed. Had done for over 30 years.

For what it costs, in my opinion it’s always worth having an immersion heater in your hot water cylinder as a back up in case your boiler fails.

 

[flameport]

Unvented system is due to be fitted in the coming weeks, not sure I want to fit an immersion at all to it, any compelling arguments as to why I would?

Very likely it will be supplied with one.
Connect it to use for hot water if the boiler breaks. It may never be used, but you will be glad it's there on the day it's needed.
Also provides the option for heating via solar if you get that in the future.

Can I extend the 2.5 mm Radial that's being used for the Immersion through a 3 Amp fused spur in the airing cupboard to power the controller/pump/boiler/valve and stat?

Yes.
Connect the immersion via a 20A switch (not an FCU).
Connect the rest via a 3A FCU.

The circuit will require RCD protection, which can be achieved by changing the fuse to a RCBO.
You don't need any isolator installing to do that - the main switch in the consumer unit will isolate the fuses in it.
However that consumer unit is life expired and should be replaced anyway.

 

[LeeJC]

Thanks JW

 

[Mister Banks]

Why do you want to move anything? With Hive you presumably have the hub next to the boiler in the garage and the thermostat/controller somewhere suitable in the house.

 

[LeeJC]

Why do you want to move anything? With Hive you presumably have the hub next to the boiler in the garage and the thermostat/controller somewhere suitable in the house.

The cabling and pipework for the boiler are quite widely spread in the garage, I'm having a partial conversion done into office space and want to minimise the foot (wall) print to just the boiler.