Household electrical switch question

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salesac1

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Hi all, would someone with more knowledge of electrics than me (not difficult) be able to tell me if this switch is fused or not? It's supplying a timer switch for an immersion heater, which suddenly stopped working (BTW the cracks evident in the plastic have been there forever, so I don't think they have any relevance....although the switch won't move to the Off position). I cleverly noticed that the little light at the top is no longer illuminated, and unscrewed the switch, expecting to see a fuse on the reverse, but there is nothing obvious. It's in a small cupboard with very difficult access, so before disconnecting the switch with the mains off, I'd prefer to have an idea in advance if I'm looking at simply replacing a fuse or having to get a brand new switch (and if so, what type should I buy?) And, if the immersion heater switch itself had packed up, that wouldn't cause the wall switch supply light to go off - right? Thanks
 

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It doesn't need an expert to see that the switch should be replaced, even if it did only have a blown fuse.
 
I’m no electrician but I have fitted a few switches & sockets in my time.
Yes your switch most definitely needs replacing and no it is not a fused switch, simply a switch with a warning neon or led warning light. I’ve never come across one where the cable exits on the face but looking closely at yours it seems it was made like that so replace it with one the same only if you feel competent to do so.
Make sure your powers switched off and insurance is up to date 🤭
 
It isn't fused. But...the fuse on your main board is blown. Replace like for like. Only you have access to the main board...none of us do.
 
How is that switch mounted? It looks well proud of the surface and there isn't a screw in the lefthand side?
 
There’s no screws in both sides as the OP “unscrewed the switch”
 
Thanks for all the quick replies, I have enough to go on now.
 
Anybody who is content with that installation while it was working should do no more then dig out the yellow pages, your standards are too low to even think about messing with mains electrical.
 
The light is neon , they do not usually 'blow' , it has no internal fuse,it is fooked. The fuse for the heater element will be on your distribution board , if it has blown it is very likely that the element in the tank blew and took the main fuse out. If you put in a new fuse it will most likely blow again unless the element is replaced.

If your distribution board has fuses on it get shot of it and fit a modern dis board. Here endeth the lesson.
 
Looks like you have two heater elements in the tank. One may be a booster the other for cheap night time electricity.

In as much as it seems easy to deal with, if you are not competent In carrying out electrical work, my advise will be to err on the side of caution. Call an electrician/plumber

Water and electricity are not best mates.
 
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You're lucky not to have had a fire.
Very often when a switch fails to operate it's due to the heat within. I would expect the contacts to be charred and creating high resistance, more heat.

If / when you attempt to replace the switch it is likely that the cable into the rear will have lost or have damaged insulation. That may be why it has blown the supply fuse.
An immersion heater should / will have its own dedicated fuse and circuit from the consumer unit.

Your admitted lack of knowledge would mean that to repair the cabling safely is beyond you. Get a sparky, it may not be a big issue, especially if he can fish the cable from under the floor locally and fit a junction box, and new 2 pole 20 amp isolating switch, with neon. The neon isn't essential, it's just an indicator.

You may find the immersion element has gone down, shorting the cct and blowing the fuse. That's a tank drain down to replace. It's possible to rupture the tank removing the old element. Assuming you have the off peak set up where the tank is with 2 elements it may be worth replacing both while drained down, if that's the issue blowing the fuse. A sparky would soon diagnose that.

That switch is still dangerous regardless.
 
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For anyone working on electrical installations on a DIY basis there is the obvious thing of wiring things correctly but the one thing that a pro electrician will usually do better is he will tighten the termination screws tighter than an amateur. Terminations that are insufficiently tightened will tend to loosen over time due to repeated heat cool cycles. Termination screws need to be tight, not so tight as to strip the threads but tight. A good tip is when you offer up a switch or socket to fit flush in it's box it will stress the cables so check again the the termination screws are tight again before finally fixing.
 
For anyone working on electrical installations on a DIY basis there is the obvious thing of wiring things correctly but the one thing that a pro electrician will usually do better is he will tighten the termination screws tighter than an amateur. Terminations that are insufficiently tightened will tend to loosen over time due to repeated heat cool cycles. Termination screws need to be tight, not so tight as to strip the threads but tight. A good tip is when you offer up a switch or socket to fit flush in it's box it will stress the cables so check again the the termination screws are tight again before finally fixing.

I wouldn't agree, it is too easy to tighten solid drawn wire so as to weaken and / or snap it.
Reasonable is to tighten and then pull the wire with a little force to ensure it's caught properly.
A 'professional' would be sure that the wires are of adequate length so as not to cause strain when fitted to the back box. Pre bending / routing the wires to reduce crushing risks is a skill developed. Watching for interference by the lugs.
My way is to cut wires as long as the most distant point of the back box, or more. To many DIY'ers will think cutting the wires short is an advantage, it 'aint.
 
Torque screwdriver is an ideal tool
 

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