Faultu isolation switch readings

[Ducksy]

Hey peps.

As on many occasions doing my electric shower repair rounds, I came across a faulty DP 40a pull cord shower isolation switch.

Why it is I always get a reading of about 70v between L-N load side when these switches fail.

It's always puzzled me why not 120v or 180v......nope always the 70v mark.

And the reading between N-CPC is 200v ? Why is that.

Could someone please explain the reason for this and what is actually happening inside the isolator switch for me to get readings like this.

Thanks.

 

[oldtimer]

Well first of all you will be testing with a multimeter fine but these will also pick up induced or ghost voltages that just confuses things now for me I change a lot of 40A DP pullswitches and a lot of it is due to the contacts breaking down or welding on in some cases or the main culprit is slack connections. What people do not realise is copper cable gives so when you connect them into the switch you should leave it for 5 minutes after and then check the connections again.

This also happens on cooker circuits

 

[Ducksy]

ghost voltages

I'll look into that sounds scary

leave it for 5 minutes after and then check the connections again.

I didn't know that I just really tighten them down never had to go back to one I've fitted, but will bear it in mind thanks.

 

[somersetsparks]

Use an analogue volt meter, I bet those voltages wouldn't show