Advice on Electric Shower Power Switch.

[elsmandino]

Hi there,

I have a 7.5kW shower that is being protected by a 40A fuse - it is an old consumer unit, but I am hoping to get this replaced later this year.

Anyway, I have an external isolation switch for the shower on the wall outside and it has occurred to me that it might not be up to scratch.

I did some research and I have read that external shower switches require a fuse, a neon light and be double pole.

My switch is white with a red switch mechanism (no light on it) and I had a quick look inside and there is no fuse (I assume I am looking for a larger version of a plug fuse?).

Do you think I should replace this switch and, if so, with what rated fuse?

Also, two quick questions, just for my own learing:

1. Why does this switch have to be fused, given it is protected by the fuse in the consumer unit. Is it simply a belt and braces approach?

2. What exactly is a double pole switch as compared to a single pole and why is required for shower switches?

Thanks very much.

A

 

[echoes]

Research where?

Your shower switch sounds fine as it is. They don't make 45A double pole switches with fuses. You are confusing that with an FCU, for which maximum fuse size and rating 13A.
The cable and shower are protected by the 40A fuse in the consumer unit.

1. It doesn't
2. Double pole means that the switch disconnects both Line and Neutral conductors.

 

[seco services]

1. Why does this switch have to be fused, given it is protected by the fuse in the consumer unit. Is it simply a belt and braces approach?

It don't but needs to be 45/50 amp.
Who told you that ?

2. What exactly is a double pole switch as compared to a single pole and why is required for shower switches?

DP when isolated breaks the live/neutral not just the live.

 

[seco services]

echoes your to fast.

 

[PrenticeBoyofDerry]

The switch does not need to be fused, the fuse/device at the fuse box/consumer unit is protecting the circuit.
The only additional protection needed would be a 30mA RCD, but that will come with your new CU.

 

[OwainDIYer]

It doesn't have to have a neon light.

It does have to have a mechanical on/off indicator. With a rocker switch this is provided by the position of the rocker, with a pull switch there is a little flag that rotates (because you can't tell if a cord is pulled or unpulled)

 

[echoes]

echoes your to fast.

It's eventually happened!

 

[elsmandino]

Thanks very much guys - it seems that I have become massively confused over issues that aren't there! Bit of a beginner in terms of electrics.

Bottom line - nothing wrong with the switch, leave it alone.

Thanks.

 

[elsmandino]

One other quick question if I may.

My instruction manual says that I need to really put in a 32A MCB in, in place of my existing 40A one.

I was going to swing in by Screwfix tomorrow night, but I have noted that there are quite a few.

http://www.screwfix.com/search.do;j...b2zkB8SW1vcq2L1!-1446469169?fh_search=32a+mcb

I know that I need a type B, but what brand? Is there one that is renowned as the best and does costs equal quality with these things?

 

[echoes]

Provided that the shower was correctly installed in the first place with the right sized MCB for the cable, then I would leave the 40A MCB in place. If in doubt, have an electrician check it.
The MCB protects the cable from overload and faults.