Immersion Heater

[kai]

Advice above spot on.

The circuit to feed the immersion doesnt required an FCU, just a 20amp DP switch if fed directly from the board on a 16amp breaker, and 2.5mm cable (usually, although volt drop etc may require a large cable).

You use the Immersion for Econ7?? Does this element not come from a switched CU?? Do you have a 24hr time clock adjacent the tank??

That was news to me... My IEE On-site Guide to BS7671:2001, states that an immersion requires to be fed from it's own circuit and controlled by a FCU complying with BS1363 Part 4?

 

[Lectrician]

FCU?? Not required if on its own circuit.

 

[ban-all-sheds]

My IEE On-site Guide to BS7671:2001, states that an immersion requires to be fed from it's own circuit and controlled by a FCU complying with BS1363 Part 4?

No - I think if you read it again you'll see that it says they are to be supplied through a "switched cord-outlet-connection-unit". Such as one of these:

Although I must admit BS 1363-4 is indeed the specification for 13A fused connection units, switched and unswitched.

 

[moosehead]

Just saw 'Rough Science' on BBC2.

They were using a metal pencil sharpener as a means to prevent corrosion on a wire in a marine environment. Apparently they contain magnesium.

 

[mapj1]

Indeed they do, a mix of copper oxide and ground up metal pencil sharpener can be used to perform emergancy thermite style* welding on copper cables when there is no power for the soldering iron. Its a very good substitute for ex-olax I can assure you.

So, all you need to do to reduce corrosion in your tank is to screw a number of old pencil sharpeners to the inside....
M.

it must be late!
* the original thermite reaction is aluminium powder and iron oxide, and can be used to join or cut steel up to the dimensions of railway lines when far enough from civilisation not to be arrested, or if you work for the railway. I had the benefit of a very permissive chemistry teacher, and suffered an early failure of the sense of danger.