Switching out Immersion switch old for new - wiring?

sapper

Hi - is it just me or are replacement switches always completely different to the switches they are replacing?

Im a strictly like-for-like electrician so hoping someone can tell me how to wire this new immersion (bath/sink on/off) switch..

with the wires currently going into this old one...

Grey cable is coming from the mains. White cable going to the immersion...

Thanks in advance!

salmocab

The grey cable is your mains supply and the insulation looks like it’s perished.

on the other cable brown and black are sink and bath (cant remember which is normally which) there also looks like a loop is needed of brown from L out to the terminal by your thumb where 250 is written. Blue is neutral of course.

Why is there no back box? Between the perished cable and lack of back box I’d hazard you have a bit of an issue with your wiring.

meercat

https://www.boards.ie/discussion/2058237354/switching-out-immersion-switch-old-for-new-wiring

The insulation on the neutral supply looks brittle/burnt and deformed (possibly from loose connection)

youll. Need to strip it back to get a good connection

sapper

https://www.boards.ie/discussion/comment/118784648#Comment_118784648

For some unknown reason the last tenant in the house destroyed the box and switch into 2 halves and then taped it back up. I suspect they didnt own a screwdriver. I have a new back box ready to go...tks for your help!

kirk.

https://www.boards.ie/discussion/comment/118784648#Comment_118784648

Blue is bath on that , would have been old colours if I recall

Should be confirmed when connecting always regardless

salmocab

https://www.boards.ie/discussion/comment/118786801#Comment_118786801

Actually on a second look I think you’re right.

kirk.

Ya that was a very old configuration , blue as bath

I've seen brown and black as either sink or bath on newer models so it should always be confirmed , takes a few seconds

kirk.

Good chance there the immersion has no 30ma protection with the age of wiring and heater probably too

Heater could have been faulty a long time there .Should also be checked for 30ma.protection anyhow

dazed+confused

The damage to insulation is the result of a loose connection.

Possibly due to the intervention of a "like for like electrician" in the past.

kirk.

https://www.boards.ie/discussion/comment/118786867#Comment_118786867

No, not necessarily at all

10-10-20

https://www.boards.ie/discussion/comment/118784661#Comment_118784661

Yes, there appears to be significant degradation or damage to that feed cable with visible damage to the black and read insulators. I'd be replacing the whole cable pronto as you can be guaranteed that the element-end is just as bad, if not worse.

kirk.

https://www.boards.ie/discussion/comment/118786977#Comment_118786977

Job for a spark that one , switch may need to be replaced too and check for rcd

10-10-20

https://www.boards.ie/discussion/comment/118786997#Comment_118786997

That's fair enough. Hopefully the OP can obtain the services of such.

kirk.

https://www.boards.ie/discussion/comment/118787381#Comment_118787381

Was reading it wrong anyhow op is replacing switch not heater here

Should be checking bath/sink , Heater IR and rcd protection there anyhow , still applies in this case as work looks old

kirk.

https://www.boards.ie/discussion/comment/118786808#Comment_118786808

Had another look at the pics there, blue is the 2-way so would be sink in theory but could be anything there looking at that

I just seen that OP said "like for like" , That's a problem right there in these scenarios as you need to be able to confirm your work and what the extent of it should be

Bruthal.

It is very important to check the setup there. Connect the neutral incorrectly going to the immersion elements, and the stat can be bypassed.

kirk.

https://www.boards.ie/discussion/comment/118789804#Comment_118789804

19/25/44 if memory serves are roughly the numbers to remember

The variety of switch layouts don't help the DIY person either and the L1 L2 markings ,plenty of scope for error

No rcd protection on older boards isn't great, a lot of faulty heaters connected . Important to upgrade to rcd and/or IR test heater

Bruthal.

Those numbers sound about right. Yea I changed a few elements years ago where the element core was open to the water. Ye could hear the sizzling sound rather than the clean buzz if ye put ear to cylinder.

kirk.

Many's the heater was running faulty before they were put on the rcd if I recall

They were a nightmare too when the switches were in the hotpresses.Sparks stopped changing them too many problems with leaks .

Even plumbers are not too keen

Not sure are the incaloy models common or much better than the copper which don't always last long

Bruthal.

They can be a pain alright. Cylinders themselves are pitted or corroded so they are thinner. They fail when removing the old element I found on occasion. Element spanner and hammer methed used at times. I think the element spanners with the offset arm added to the problem, encouraging a twisting force to the element in the undesired plane.

One or 2 I cut the hole and fitted the flange years ago which was easier than removing elements from cylinders. It was cylinders which had no element fitted. Or no flange at all.