Hi,i`ve got aproblem with my electric shower.The old one bit the dust and I got a compatible replacement.Worked fine at first but after a couple of days I noticed a smell.Which turned out to be the Isolator switch getting hot.Thinking it was a faulty switch I replaced it.when I switched on, it blew the fuse and burnt out the isolator switch.I replaced the switch again,carefully.The switch jammed up and I noticed the fuse(yes fuse)was getting warm.With my multimeter I found there is continuity between neg and earth.I`m starting to get a bit bothered.I would really appriciate any help/advice.
My new shower/headache
- Thread starter p0rkypie
- Start date
The burnt isolator was probably a loose connection. However you will now have to cut away the ends of the wires until you get to bright copper, otherwise the same problem will happen with every new switch you fit.
Fuse - what size of fuse, and what is the rating of the shower?
Fuse - what size of fuse, and what is the rating of the shower?
How and where did you test the continuity between earth and neutral?
If you were testing towards the fuseboard, was the main switch off - I do hope so.
If not, that's a very dangerous thing to do. Also neutral and earth will appear to be connected.
some Qs
What is the rating of the "compatable" shower,
what was the rating of the old one
and what is the size of the fuse in the shower circuit
what is the csa of the cable
If you were testing towards the fuseboard, was the main switch off - I do hope so.
If not, that's a very dangerous thing to do. Also neutral and earth will appear to be connected.
some Qs
What is the rating of the "compatable" shower,
what was the rating of the old one
and what is the size of the fuse in the shower circuit
what is the csa of the cable
Did you get the L and N and in and out connections right.
Sounds like you did not and created a dead short across the switch when you turned it on.
I had the fuse out while testing the continuity at the supply wires for the isolator switch.The new shower is the same rating as the old one.The switch is 50 amp,surely it would not get hot unless something else was wrong?
ever seen a welder in action? that's a high resistance connection between the wire and the thing being welded..
same thing happens on a smaller scale in a loose connection in a switch..
same thing happens on a smaller scale in a loose connection in a switch..
No No No!!!
The fuse only disconnects the LIVE conductor.
If you still had the main switch on then the neutral is still connected to the supply and you will measure continuity between earth and neutral because they are connected together at the electricity company's supply transformer.
Don't do continuity tests with the supply connected, that means disconnecting live AND neutral. On most domestic installations that means turning off the MAIN SWITCH.
A bad connection = electrical resistance in the connection. Resistance causes heat to be generated when current flows. That's why thin wires can take less current than thick ones, a thinner wire has a higher resistance and therefore heats up more for a given current than a thick one.
Nevertheless, your description of what happened is entirely consistent with having wired the switch 90° out.
That switch, BTW
is probably knackered now.
Let's put it this way - each bar in an old fashioned electric fire draws just over 4A.
Light bulbs where the filament gets white hot and would vaporise were it not for the inert atmosphere draw fractions of an amp.
Why have you got a 30A fuse for a 35A load?
No a welder in action is a short - circuit !
Right, I attacked the shower tonight.Cut back a couple of inches of the cable,stripped it,reconnected it and it is all ok (sort of).The new shower is approx 1000w more than the old one(only found this out Tonight).I ran the shower for bout 10 mins.The cable started to get "warm".I presume 4m cable is used when it should be 6.Yes the fuse is 30amp when it should be 35.I did`nt see 35amp fuse wire .I shall have to get something more contemporary.Guess I`m going to have to rewire it.Does¬nt look to bad a job.
Please get an electrician to do it for you.
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