Wiring an old immersion - can anything go wrong?

FreeBear

Qyburn said: If you go ahead, remember to use heat resistant flex, should be available by the meter from EBay, you will need 3 core 1.5sq.mm.

1.5mm² cable is good for ~12A - Marginal for a 3KW heater. 2.5mm² would be preferred, and only slightly more expensive.

Belenus

Qyburn said:

surreygirl said:

The gas engineer said that although the illuminated immersion switch was on, it was not actually wired into the hot water tank - hence no hot water. It now seems that I'll need a new boiler installed. The wiring panel for the immersion is in the bottom 1/4 of the tank. 

Is there any risk from getting this wired in?

Can you post a couple of pictures? The immersion heater where the cable should go, and the switch. If you go ahead, remember to use heat resistant flex, should be available by the meter from EBay, you will need 3 core 1.5sq.mm.

2.5 sq mm should be used.

Edit: I had not seen FreeBear's post above. I agree with it.

Qyburn

Heat resistant 1.5sq.mm is rated for 16A, for example ..
https://www.tlc-direct.co.uk/Products/CA1dot5HR3slash1.html

But I guess there's no reason not to play safe with 2.5, if the switch and heater terminals and strain relief will accommodate it ..

https://www.electriciansforums.net/threads/immersion-heater-in-1-5mm-flex.108174/

FreeBear

Qyburn said:

Heat resistant 1.5sq.mm is rated for 16A, for example ..

Depends on what you consider to be a reasonable temperature rise. I don't like hot cables...

But yes, good point about the terminals & grommets being able to accommodate 2.5mm².