shower switch burning out

[shiznit76]

Hi, for the second time in a year the shower power switch outside my bathroom has overheated and melted inside causing the shower to trip out, what could be causing this? Both time its seems to have happened in the morning when all 4 in the house have been going in for showers one after the other

 

[crystal ball]

Usual cause is loose connection

 

[shiznit76]

its a 20amp switch, I'm thinking I need to change to a higher one rather than a loose connection as the wires were all still in the connections fine but the plastic inside showed signs of melting and soot

 

[crystal ball]

When you say a power shower is it a pumped shower using hot water from the house system or does it heat cold water itself

 

[shiznit76]

it is a cold water fed electrical shower

 

[bernardgreen]

Do you use this switch for turning the shower ON and OFF instead of the switch on the shower itself ?

Not all isolator switches will withstand frequent switching of a load ( the current to the shower ). The contact faces wear and become resistive which results in heat being generated inside the switch

 

[crystal ball]

Instantaneous showers normally use upwards of 30 amps, I usually fit 50 amp switches, your 20 amp switch is not suitable for shower ampage

 

[shiznit76]

it turns the power on to the shower then press the on/off button on the shower to turn that on

 

[omega015]

What switch have you been using? can you link to the exact on you've bought? Did you replace or an electrician? Can you show us some photos of the melted switch?

 

[bernardgreen]

it turns the power on to the shower then press the on/off button on the shower to turn that on

Do you press the on/off button to turn the shower off before turning the switch off. It is switching OFF that the most wear occurs, When switching OFF there is an arc between the contacts and this arc does the damage to the contact faces,

 

[shiznit76]

yes turn the shower off at the shower, not the 20amp switch which is outside the bathroom

 

[shiznit76]

What switch have you been using? can you link to the exact on you've bought? Did you replace or an electrician? Can you show us some photos of the melted switch?

switch same as this
http://www.toolstation.com/shop/p64900?table=no

can't post pics just now as at work

 

[omega015]

Do you know what kw your shower is? What rating is the mcb/fuse protecting the shower circuit? Ideally the switch should be matched to the mcb (and of course both be suitable for the shower)

 

[shiznit76]

Do you know what kw your shower is? What rating is the mcb/fuse protecting the shower circuit? Ideally the switch should be matched to the mcb (and of course both be suitable for the shower)

I will get back to you when home. It's a 10.5kw shower, I know that much off hand

 

[omega015]

If its 10kw then a 20a switch is not suitable. Report back on what mcb you have anyway but you will need a 45/50a switch based on the 10kw shower. Have you always had this rating shower or have you upgraded/changed at some point?