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How to test an electrical switch?

Community Veteran
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Registered: 24-09-2008

How to test an electrical switch?

Our shower has 'gone cold', by a process of elimination, one (or possibly two) of 3 identical switches have blown.
I've spares and a meter. Rather than do it by trial and error, Can somebody give me guidance on how to test if a switch is now broken.
The switch is similar the one photographed. (there is a 'black toggle' on the reverse side, its normally open, close to activate)
9 REPLIES
Community Veteran
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Registered: 06-11-2007

Re: How to test an electrical switch?

assuming it is a "straightforward" open/closed switch,  with no internal electronics, then put your meter on a OHMS Resistance measurement 2,000 ohms... then put the prods on each terminal...
if the meter moves across the scale to Zero, then the switch is ON... if there is no movement then the switch is Open Circuit, or OFF... ( check the meter movement by putting the prods together before you do the switch)
If you have a means to "activate the switch" externally then it should be obvious when using it, whether the switch is working or not....
pierre_pierre
Grafter
Posts: 19,757
Registered: 30-07-2007

Re: How to test an electrical switch?

and if you havnt got a meter, try someone like maplins etc, you can get one cheaper than the switch
Community Veteran
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Registered: 27-05-2011

Re: How to test an electrical switch?

I would use a neon type screwdriver where you touch live wires at 240v and if you have your finger on the end of the screwdriver and the neon lights you have 240v at that point.
Then you can check if the circuit is energised up to the heater also if you have 240v on the negative side where you shouldn't have!
To do is to be - Neitzsche
To be is to do - Kant
do be do be do - Sinatra
Community Veteran
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Registered: 24-09-2008

Re: How to test an electrical switch?

@shutter thanks, by depressing the 'black toggle' I can activate the switch (normal is off),
@pp thanks, I have a meter, every time I come to use it the battery is flat, now on charge, job lined up for the morning.
@Peter, think I understand, thanks, but it is a shower switch, to have the switch 'on' water is running, I don't feel confident playing with electricity and water.
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Re: How to test an electrical switch?

Shower electrics have to be absolutely safe due to the presence of the water so take care with any repairs. Smiley
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Community Veteran
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Re: How to test an electrical switch?

Reality check  Wink
If your shower is the same as my shower it is fitted with neons anyway. So depending on which heater is switched on that neon will glow and there you have confirmation of what that switch is doing!
Yes  Roll eyes
To do is to be - Neitzsche
To be is to do - Kant
do be do be do - Sinatra
Community Veteran
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Thanks: 44
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Registered: 24-09-2008

Re: How to test an electrical switch?

Thanks all, shower now works again..... Cool Cool
@peter, no neons, it is over 20 years old
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Re: How to test an electrical switch?

Crikey.....it doesn't owe you anything then Smiley
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Re: How to test an electrical switch?

nothing in our house is under 20 years old! except the dog (but he is 35 in dog years)  Wink
Ive just had a thought we have a HD TV and Sky box the wife insisted on  Lips are sealed
To do is to be - Neitzsche
To be is to do - Kant
do be do be do - Sinatra