Electric shower burning switches

[JustinScot]

hi,

I installed a new triton 10.5kW electric shower about a year and a half ago and it has now burnt through 3 switches. At first I thought it was the switches. but the latest one has the wires burnt out ...see pic.

This piece of burnt wire was removed and i installed a new switch but a week later it is tripping the circuit breaker. All switches i installed were 45A

The previous shower was 8.5Kw and ran fine for 3 years.

Do I need to get the wiring checked? Replace the shower? Downgrade to 8.5kW?

 

[EFLImpudence]

The heating is caused by loose connections - and possibly squashing the switch back into position.
You may think they are tight but they (or one) wasn't.
It should not trip a breaker, though. This could suggest something somewhere else is damaged.

These are considered better because the conections are made in situ and a cover goes over them - although, as you can see, they are round so they might not fit the existing hole in the ceiling.
https://www.screwfix.com/p/crabtree-50a-1-way-pull-cord-switch-white/90597

 

[Jackrae]

What make of switches are you using. 45A switch feeding a 10.5kW shower is really pushing its rating. Get a 50A quality switch and ensure you cut back all heated copper until you get to bright copper.

 

[JustinScot]

Do I need to get the wiring checked?

 

[JustinScot]

What make of switches are you using. 45A switch feeding a 10.5kW shower is really pushing its rating. Get a 50A quality switch and ensure you cut back all heated copper until you get to bright copper.

Last one was British General
https://www.screwfix.com/p/british-general-45a-1-way-pull-cord-switch-white/65167

 

[EFLImpudence]

Do I need to get the wiring checked?

You need to find out why the breaker tripped.

Was it an MCB or an RCD? RCDs have test buttons.

 

[Jackrae]

Useful information would include the rating of the "breaker" that "tripped" and at what point in time did it trip (immediately shower was used - during shower use after 'x' minutes - at some other time) Also what is the cross section of the cable running from the CU to the shower and what is its length. All this information is required to determine whether your upgrade is on sound foundations (excluding any defective switches)

 

[EFLImpudence]

All that is true but only one wire has overheated so a loose connection is still the likely cause.

 

[gman76]

Is that a black wire in the earth terminal?

Edit: And why is there only one earth wire for two cables?

 

[EFLImpudence]

I think there are two cores in it

and -

assume black sleeve (a bit of insulation of the other core/) has been used.

 

[gman76]

Fair enough - it does look like two after a second look.