wiring for a 1kw immersion heater

[waterdog]

We recently had to replace our calorifier and the new one (surecal 55l) came with a 1kw immersion so we are toying with the idea of wiring it up.

At present we get hot water via the engine or the Eberspaecher but will be in a marina for some of the winter so might as well take advantage of the hook up. 

 

We already have a dedicated socket for the washing machine that only works via the shoreline or from the travelpower and I was thinking of connecting to this and fitting a double pole illuminated switch, which unless I've missed something should be fairly straightforward.

 

The second potential plan which I'm not too sure about, is to wire the immersion to the "normal" 240v circuit. We have 1.2kw of solar and a 2kw psw  inverter with a nominal 520ah battery bank. Would the solar cope with an immersion on a sunny summers day?

I'm thinking of when we moor up for a few days when out cruising and trying to avoid running the engine. 

 

 

[Alan de Enfield]

Do not power the immersion from the batteries - it will be drawing 100 amps.

I have a 1300Ah battery bank and mistakenly left the immersion switched on when we left the land line - within 'hours' the low battery alarm was sounding.

 

In theory your solar should cope with it, but when the sun goes to bed you must immediately remember to go and switch the immersion off.

Don't risk it.

 

Plug it into your land line / travelpower powered socket (the washing machine one).

 

Keep it simple.

 

 

 

Edited September 2, 2019 by Alan de Enfield

[waterdog]

2 minutes ago, Alan de Enfield said:

Do not power the immersion from the batteries - it will be drawing 100 amps.

I have a 1300Ah battery bank and mistakenly left the immersion switched on when we left the land line - within 'hours' the low battery alarm was sounding.

 

Plug it into your land line / travelpower powered socket (the washing machine one).

 

Keep it simple.

 

 

 

Thanks Alan, You have confirmed my feelings, option 2 just didn't seem right but it was worth asking the question.

[canals are us?]

I wired my immersion heater of 1.1kw from the consumer unit using a 10amp MCB and using 2.5mm arctic blue to an digital immersion heater timer located in wardrobe, then used white 2.5mm heat proof cable to the immersion heater. I used the older LAP timer from screwfix.

 

Works well as liveaboard at Marina. Just don't run 2 power hungry items together. My bollard is rated 16amp. Around 3.5kw?

 

James.

[David Mack]

56 minutes ago, waterdog said:

 

The second potential plan which I'm not too sure about, is to wire the immersion to the "normal" 240v circuit. We have 1.2kw of solar and a 2kw psw  inverter with a nominal 520ah battery bank. Would the solar cope with an immersion on a sunny summers day?

 

Your 1.2kW if solar will only produce 1kW of electricity in the best of conditions - middle of the day, really bright sun, panels angled at 90 degrees to the sun's rays etc. And even then it might not, once you allow for wiring and controller losses etc. So the immersion will always be drawing at least some power from the batteries (as well as all your other electric power needs). So you will run your batteries down - slowly on a bright day, quite fast on a dull day. And that's without including the occasions when you will forget to turn the immersion off at night...

Edited September 2, 2019 by David Mack

[jonathanA]

2 hours ago, waterdog said:

 

 

We already have a dedicated socket for the washing machine that only works via the shoreline or from the travelpower and I was thinking of connecting to this and fitting a double pole illuminated switch, which unless I've missed something should be fairly straightforward.

 

 

 

 

Personally I’d use a switched fused spur unit with a neon indicator. 

 

Its only a 1KW unit so only a 4A draw.

[blackrose]

3 hours ago, Alan de Enfield said:

Do not power the immersion from the batteries - it will be drawing 100 amps.

 

 

What he said.

 

You'd be crazy trying to use the easily depleted chemical energy in your batteries to heat a big tank full of water!

 

I wired up a timer to my immersion heater which I only use when on shore power.