Immersion heater switch

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I'm planning to install a new switch for the immersion heater. Currently there is a socket in the airing cupboard, which the immersion plugs into.

This socket is on a dedicated circuit and the consumer unit has a circuit breaker marked "water heater". It does not indicate any amps other than "B 16" whatever that means....

I've been told to use a double pole 20A switch - what does the 'double pole' mean?

Also suggested was a cooker switch (32A) though not sure why!?

Screwfix have two switches which seem to be similar except one has 'water heater' written on it! Will they both do the job?

http://www.screwfix.com/p/mk-20a-dp-water-heater-switch-with-neon-white/81306

http://www.screwfix.com/p/mk-20a-dp-switch-with-neon-white/13014

Anything else I should consider?

cheers.
 
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Either will do but you must ensure that the heater is on it's own breaker as you suggest. Please remeber to isolate before working and ensure that the terminations are sound and correct.
 
B16 means it is a 16A type B Miniature Circuit Breaker - fine for an immersion heater.
Double pole means it switches both live and neutral. Single pole just switches the live.
32A is a bit pointless - a 20A flavoured one is fine.
Either of the screwfix ones will be fine, the only difference is the lettering on the front.
 
Use the one marked Water heater on screwfix - It may be an opportunity to fit a timer for the water heating, to help save your electric bills at the same time.
Set the timer for the minimum period you can get away with, and if the hot water runs out, you can increase the timing a little bit.
 
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Use the one marked Water heater on screwfix ....
Any reason other than the wording?

Supplementary Q:

I've now bought the switch and the instructions show the "circuit cable" entering at the top and the "cable to appliance" exiting at the bottom.

Because of the location (near floor level) and the limited length of supply cable coming up through floor, I had planned to bring the supply ("circuit cable") up from below.

Is there any reason one cannot reverse the connections provided in the instrucions?
 
it will mislead anyone who works on it in future

it has an indicating neon, which will not work properly.
 
Do a proper job and extend it. This means the switch will be in a sensible position too.
 
Nuts!

mount upside down!? so switch will operate in reverse (and has 'on' written on it which will show when it is off!).

Neon light won't operate? Or will operate in reverse?!

Double nuts!

So are 20A 2 pole switches available that are designed for bottom-entry circuit cable?......
 
It doesn't matter if the cables enter the back box or pattress from top, bottom, left or right as long as they connect to correct switch terminals.
 
Neon light won't operate? Or will operate in reverse?!
The neon would be permanently lit regardless of the switch on or off

The switch would still be "on" only in the marked "on" position regardless of the supply/load connections reversed or if the actual switch was mounted upside down or the correct way
 
Neon light won't operate? Or will operate in reverse?!
The neon would be permanently lit regardless of the switch on or off

The switch would still be "on" only in the marked "on" position regardless of the supply/load connections reversed or if the actual switch was mounted upside down or the correct way

Makes perfect sense. Thanks.

Nice chap at a local electrical suppliers gave me one which does the job. Screwfix refunded the previous one.

Sorted. Many thanks everyone!
 

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