Electric Shower Help!!

[David Burgess]

Hi All. Hope someone can help here as I'm confused with all the info floating around all over the net.

Our shower blew its PRD last night and we were going to buy a nice new upgrade.

Having removed the cover the get the rating we discovered a 9.5kw HOWEVER, the shower is connected with (old red & black) 6mm T&E with a 32A MCB switch in the consumer unit. No idea what rating the pull switch is.

My understating is that a 9.5kw should be running with 10mm and a 45A MCB with a 45A pull switch??

The shower has seemingly been running like this for 6 years since the bathroom was done with no issues... but as above, it seems wrong and am surprised we havent burnt the house down.

Work was all done and tested and signed off, no bodging as far as I was aware but obvs I'm now questioning that!

If it helps, the cable runs from under the stairs, around 8-10 meters to the pull switch, through floor and standard stud walling.

Any advise here would be fantastic before I get a sparky in as I would like to understand this.

Many Thanks in advance

 

[telectrix]

9.5 kW (40A) is just about the limit for 6.0mm cable as long as the cable is not installed in insulation. a 32A MCB will stand 40A for a good while before it trips. showers tend to be on for 10 -15 minutes , such short duration is OK for bot cable and MCB. that's why you've had no problems. just be aware that if you uprate the shower, that's when you'll need 10mm cable.

 

[David Burgess]

The shower the other half wants is a bit less at 9kw.

If I asked a sparky to replace my MCB for maybe a 40A and fit the new 9kw Shower, A, do you think that's suitable and would suffice & B, would a sparky be happy doing that or would they insist on fitting the 10mm?

Id rather be as safe as I can with it, as you have said it' only on for 10-20min a time so heat build up isn' a problem I don't think, but I'd rather not have to add hundreds to my bill by having to replace the cable

 

[buzzlightyear]

the shower circuit cable is it RCD protected if not by changing the shower it needs to be done.

 

[David Burgess]

Yes, RCD is part of the consumer unit and is 80A rating.

 

[buzzlightyear]

you must remember not all showers are the same for water inlet
and cable entry .

 

[buzzlightyear]

who's make of shower is installed now ?

 

[Taylortwocities]

If I asked a sparky to replace my MCB for maybe a 40A and fit the new 9kw Shower, A, do you think that's suitable

Why do you need to do this??.
Has the MCB ever tripped with a larger load of 9.5Kw?

 

[DPG]

My shower is a 10kW and is on a 6mm cable (yes I know). It's a short run and is not in insulation and the cable barely gets warm. Not saying it's right, just thought I'd try and stop you thinking your house will catch fire.

It's more likely to catch fire from loose connections, etc. to be honest. Sorry, that's not helping now is it

 

[buzzlightyear]

9.5 kw divided 230=41 amps