I had a bit of trouble with out immersion heater the other day. For some unknown reason it came back to life whilst I was testing it but I was confused by the wiring in the switch.
Take a look at this image.
The earth wire with the red sleeve goes to the earth terminal on the immersion. Can anyone explain what that's all about.
Mike
Are you certain of that regarding the earth wire going to an "earth" terminal? What are the connections for the immersion heater?
A guess is the RH terminal (on/off)are a Double Pole Double Throw switch, and the LH terminals are for a changeover (bath/sink).
If so I would have preferred the changeover to have switched the live side, but hey!
Any chance of an in-focus photo?
Not now I've put it all back together, it snot very sharp I know but the cable colours are clear.
Mike
quite simple. The red sleeve is part of a crimp-on connector. The sleeves on these indicate the size of cable the connector will accept. Nothing to do with the colour code of the cable itself. If I'd done the job, I'd put a turn or two of G/Y over the red.
The earth with the red sleeve definitely goes to the earth screw on the immersion heater. Brown to the Immersion thermostat, Blue to Immersion negative.
Black and Red from the fuse board.
Mike
No its definitely a sleeve, but its the way its wired that confuses me. Earth from the mains goes to the frame of the switch whilst earth from the Immersion has this red sleeve and goes into the switch!
Mike
While that sounds plausible for the immersion end, it does not explain what is going on at the switch end...
a clearer photo would help.
This seems to be the switch in question - or at least one functionally similar:
Anyway, looks very much like a CPC has been reused as a live (or neutral) - Code 1 failure - definitely not allowed and for good reason
Is it definitely connected to earth? I've never seen a CPC have a terminal *in* a switch like that - CPC parking terminals are usually off to one side or done in the back box.
If that was a neutral connection, it might still work but in a very unsafe way.
Not convinced by any of this and the photo is sadly too unclear to be sure what the terminals are for.
It looks like there are two flexes - one is the power in, and the other the feed out to both immersion heaters. The power in connects to the on/off switch and the earth terminal. The flex out needs two switched lives and a neutral, so they have used the neutral plus the life as one of the switched lives, and then re-purposed green/yellow conductor as the other switched live.
The only bit that does not tie up is the red sleeved earth wire going to the earth on the immersion - are you sure its that one and not another?
I am 70% certain from what you just said that this is wrong.
I'm 100% certain if it were mine, I'd want to open it up and run a full test with a multimeter or test lamp to work out exactly how it was wired.
I take it you have no RCD on this circuit?
I don't know, but I do know that I don't like the look of it at all.
Philip
There is only one immersion heater, and yes I'm sure that earth wire with the red sleeve only goes to the earth terminal on the body of the one immersion!
Mike
Your pic doesn't come out well here - but it could be the sparks who installed it had run out of green/yellow sleeving so simply used a bit of red instead. Or was too tight to buy the correct stuff. ;-)
What I would expect is that the two wires from the bath / sink switch would go to two different terminals on the immersion heater - one to power the long element that heats the whole tank for baths and one to power a much shorter element that heats just the top of the tank, for sink use. If that is not what happens, it is wired wrong. If it is and the sleeved earth wire feeds one of the two heater elements, it is still wired wrong.
Colin Bignell
As I have said before, during similar discussions, the guy who wired my central heating years ago used the CPC for a switched line in a length of twin and earth, long since replaced with 3 core and earth. Maybe it's a plumber thing?
Going back to the OP's comment of "For some unknown reason it came back to life whilst I was testing it " Maybe it would be worth while having the switch off again and trying to figure out why it came back to life and also take a better photo at the same time. Intermittent problems can be a pain to find, but very satisfying when you do.
If there is only one immersion heater what does the sink/bath switch switch? (Confused) Does any one produce a heater with 2 elements? Could the red sleeved CPC be going to a second terminal on the heating assembly? I have an element with large brass terminals that could, possibly, be mistaken for an earth terminal. Any chance of a photo of the wiring on the immersion heater element itself?
Are you sure that is not a dual element heater? It would make sense given the second switch... A photo (in focus) of the connections to the immersion may shed some light.
It's a "being unsafe and should never be allowed to touch electrics" thing. So I guess you're right ;->
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