electric shower not working

[alb200]

I have had an electric shower for several years which has suddenly stopped working. I am getting power to the shower as the red light comes on, but when I turn the shower on the red light goes out and there is power travelling down the neutral line. It is a 8.5kw shower run with 6mm cable - there seems to be some burning on the neutral wire at the 45amp switch - do I need to replace the wiring as I have replaced the switch with no effect.

 

[pjcomp]

The "burning on the neutral" is where the wire has previously been loose in the terminal, leading to arcing which, over time, has degraded the copper and brass and caused your problem. The wiring needs to be cut back to a point where it is undamaged (you can tell when you reach this point as the copper will be malleable instead of rock hard), then refitted to the terminals. Hopefully the original installer will have left enough slack cable for this to be achieved, otherwise extending the cable will become more interesting.

When you refit the switch make sure the terminal screws are properly tight otherwise you'll have a repeat of the problem in a year or two.

PJ

 

[alb200]

The "burning on the neutral" is where the wire has previously been loose in the terminal, leading to arcing which, over time, has degraded the copper and brass and caused your problem. The wiring needs to be cut back to a point where it is undamaged (you can tell when you reach this point as the copper will be malleable instead of rock hard), then refitted to the terminals. Hopefully the original installer will have left enough slack cable for this to be achieved, otherwise extending the cable will become more interesting.

When you refit the switch make sure the terminal screws are properly tight otherwise you'll have a repeat of the problem in a year or two.

PJ

Thanks for that - I will probably just renew the complete run again. Is it alrightto use 6mm cable for the 8.5kw shower or do I need to go to 10mm

 

[EFLImpudence]

Is it alright to use 6mm cable for the 8.5kw

Yes - but keep it away from any thermal insulation.

 

[alb200]

I have rewired the whole cable run in 10mm - still not working. However when I looked more closely at the Memera 2000 cu - I found that the neutral side had gone completely. The switch that is now burned out was a 63A pod - I have a spare rccb rated at 80A, can I use this or will I have to replace with original main switch pod?

 

[EFLImpudence]

Not quite sure which is what.

Can we have a picture please?

Or a description of all the breakers left to right.

 

[alb200]

Not quite sure which is what.

Can we have a picture please?

Or a description of all the breakers left to right.

Untitled

• alb200
• 5 Jan 2013
• 1

Untitled

• alb200
• 5 Jan 2013
• 1

the 1st picture shows the cu as it is, but I need to replace the right hand side as the neutral line is not working. The 2nd picture is what I want to replace this with - part on the left is the original (straight swap) part on the right is a 80A rccb - hope this makes sense.

 

[EFLImpudence]

Yes, it should have been an RCCB all along (unless it has been there for a long time).

Make sure the RCCB says 30mA or 0.03A.

Also that the test button works.

 

[alb200]

Yes, it should have been an RCCB all along (unless it has been there for a long time).

Make sure the RCCB says 30mA or 0.03A.

Also that the test button works.

The rccb has 80A and also states 0.03A on it

 

[EFLImpudence]

Yes, that's good.

 

[alb200]

Yes, that's good.

Thanks for all your help - will try this tomorrow.

 

[alb200]

Yes, that's good.

Thanks for all your help - will try this tomorrow.

Sorted - many thanks

 

[EFLImpudence]

Very good.

Thanks for letting us know.