Dodgy immersion switch

[Dan12]

Hi

I've been having a problem with a water heater switch for years. But now finally as the kitchen is getting done up and the switch is already hanging out of the wall I feel like now would be a good time to fix it!

Basically the switch always sparks when turning off, I know they do this but it seems like quite a substantial spark and a pop every time its turned off.

Also the neon light on the switch always has a faint glow on it and it never comes on fully or goes off when the switch is in either position. Despite this dodgy switch the actual water heater works no problem.

I've looked at the back of the switch and all the wires seem to be in the correct places. The last time we changed the switch we unscrewed it to find burn marks and parts of melted plastic but this isnt happening with this switch.

Any ideas how it could be fixed? I know the switch doesnt affect the operation of the immersion heater but I just feel its not wired correctly or something.

 

[ban-all-sheds]

Get a new switch.

 

[plugwash]

If the light is dim/flikering that usually just means that the neon bulb is failing, the small neon bulbs used have a habbit of doing that (what I think happens is as they get older their striking voltage increases and so they only operate on the peak of the mains waveform leading to the fliker).

Some level of sparking is normal with a heavilly loaded switch but if it seems unsually high the switch should probablly be replaced.

As for the light not turning off when you switch the immersion off that almost certainly means the installer has got the feed and load connections the wrong way round.

 

[Dan12]

Thanks for the help

Just swapped the feed and load connections round and now the light comes on with the switch and goes off with it too! But yes, a new switch is needed as the light is very dim, obviously from being on all the time when it was wired the wrong way round.

 

[bernardgreen]

When you get the new switch make sure it has the correct current rating for the immersion heater.

If the spark is visible through the switch then it suggests the switch is not breaking the circuit fast enough to prevent the arc ( the spark ) forming and persisting.

Or the switch contacts are not large enough for the current it is switching. This could be because they are worn or they were never large enough because a switch with inadequate current rating was fitted.

 

[bernardgreen]

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