Wiring Immersion Heater

[ARW]

That's not a fault. That's incompetence. And you prove dead before working on a circuit or appliance.

[Tim Watts]

And you prove your prover first :) I always test my probe on a known live first.

[Harry Bloomfield]

ARW pretended :

If for any reason a main neutral is lost, the the neutral will become live.

[ARW]

What is a main neutral?

[charles]

when I started updating the wiring etc in this house (wth lighting switch in the bathroom was fed in lead sheathed cable) I found a junction box with red & black going in and black & red coming out.

[ARW]

Its not uncommon to find a junction box like that when you have only two red and two black wires into the junction box.

[charles]

you mean it's normal to join red to black and black to red inside the box?

[Tim Watts]

This is why they have MEN on TN-C-S systems.

[Adam Funk]

Is there another photo after you worked on it? ;-)

[harryagain]

The most likely test to perform is insulation and you can't do that if the appliance is still connected to neutral.

[harryagain]

In days of yore there was no twin red/brown cable, so it was common in lighting circuits. But there was single core double sheath. cable, now disappeared. The three terminal system of wiring was unknown too.

[Andy Burns]

There is still 6241Y if you want single+earth or 6181Y if you don't want an earth.

[charles]

there was twin red/black. I've still got half a drum.

by 3 terminal, I assume you mean adding an earth - or do you mean loop through?

[dennis]

Of course you can, if it fails you will have to isolate it to find the fault.

[harryagain]

Looping in and out of the ceiling rose. More sensible really. Might use a little more wire. Ie live, neutral & switch wire.

[harryagain]

It will always "fail" if connected to neutral. Since neutral (and hence the wiring in the appliance) is connected to earth

[ARW]

No. I have drawn on the correct connections. The only fault is that the outgoing connections from the second RCD are the wrong way around.

[Andy Burns]

ITYM

[ARW]

I did:-)

[Big Les Wade]

harryagain posted

But why not just an ordinary plug that you can pull out from an ordinary socket?