Immersion heater electrics

[tally100]

Hi
I have had a new Vaillant eco tec plus 615 boiler and mains cylinder fitted with an immersion heater fitted but not wired up yet, I have installed the 2.5 mains cable back to the consumer unit and need to buy a mcb to fit to consumer unit to feed the immersion heater.Can anybody tell me the amp size i need to buy. I have a friend who is an electrician ( part p) to connect up for me but he is away on holiday at present.
Thanks

p.s boiler really quiet compared to old one

 

[Softus]

You'd be better of posting the question in the "Electrics UK" forum, but it's commonplace to protect a dedicated IH circuit with a 16 Amp type B device.

 

[Chri5]

The previous answer was based on a 3Kw or 3000W element, which is standard for most IH.

Do check your IH spec.

Fuse calc is a simple 3000w / 240v = (just under) 13A

 

[Softus]

Yes, sorry - I should have stated my assumption there.

 

[ricicle]

Can anybody tell me the amp size i need to buy. I have a friend who is an electrician ( part p) to connect up for me but he is away on holiday at present.

 

[Softus]

Can anybody tell me the amp size i need to buy. I have a friend who is an electrician ( part p) to connect up for me but he is away on holiday at present.

He probably though he was being inventive.

 

[JohnD]

No, this mate travels round the country. He must be really busy, we get dozens of his friends on here every week.

 

[RF Lighting]

It's strange how this 'mate' never supplies his own gear either

 

[Agile]

And the mate doesn't know what current rating MCB is needed even though he is an electrician!

And what about the switch spur and the heat resist flexible to the element.

Another interesting question is the size of heat resist required!

Tony

 

[Softus]

And the mate doesn't know what current rating MCB is needed even though he is an electrician!

He's 'on holiday'.

And what about the switch spur and the heat resist flexible to the element.

Both of those are needed.

Another interesting question is the size of heat resist required!

1.0 mm² would take the current when cold, so just apply the relevant correction factor given the temperature next to the cylinder.