Whats the worst can happen..shower question again

[bungarm]

Okay, I have read everything I can find on this site about installing an electric shower, but have found some of the advice a bit confusing.

We have just finished renovating a two bed terrace which is now being let out to 3 students, and one of the improvements we have made is putting in an electric shower. The shower is 9.5kw, wired in 6mm (I can hear the groans already..!) via a DP pull cord switch and is less than 10metres from the CU. All the wire is tacked to the joists (none of it in trunking) and well away from other house wiring, central heating pipes etc. It is protected by a RCD and a 50amp MCB. The manufacturer recommended 6mm (yeah, I know!) so this is what we used.

So, my question is, what is the worst thing that could happen, given all the above? Is the wiring likely to melt? Is the MCB rating too high? Will the shower just pack in altogether/the RCD/MCB keep tripping? Should I take up knitting??

Any advice will be most welcome...except.....anything including the words 'ten' and 'mill'...

 

[securespark]

If you're not willing to accept advice, even that which you don't want to hear, then there's no point posting, is there?

 

[bungarm]

okay...thanks a lot...

Bye

 

[AdamW]

Well, according to the TLC cable calculator 6mm should be ok up to about 30m clipped direct (as you describe). However, if it is running in a ceiling void or loft space it will get pretty warm so 10mm would be a better bet.

As the cable is so easily accessible (lucky you have it all clipped to joists!) and 10 metres of 10mm will only cost you £16 or so, I would definitely consider upgrading it. It's a shame you only thought about this after installing it, but it has happened to us all with DIY projects: you finish a room then think "Now, what if I had done this or that differently?".

I believe that renting out a house you need an electrical inspection certificate, so ask the assessor for their opinion on it. They should be able to give more certain advice on it.

 

[plugwash]

yes under floorboards is method 1 as is burried direct in plaster

so 6mm should be ok as long as you keep loft insulation etc well away from it!

 

[dingbat]

Worst case? It's not the cable that will melt but the insulation if the cable runs too hot. If your cable is bent round a tight radius it's possible that in time the conductors can migrate through the softened (by heat) thermoplastic insulation. In the extreme this could eventually cause a short circuit and trip the MCB or RCD, depending on which conductors end up touching.

But as plug says, as long as there isn't a run through insulation, you're within the upper limit for that cable. Get a 45A MCB if you can.

 

[murraysnudge]

From my experience of letting bed-sits to young people I would advise fitting a 45A DP switch outside the bathroom instead of the pull switch.
I had one pull switch that required dismantling to fix a new cord; I never got it back together.

 

[pipme]

If you're not willing to accept advice, even that which you don't want to hear, then there's no point posting, is there?

Guess whose cage got rattled !!

 

[AdamW]

Guess whose cage got rattled !!

He's just upset about the new methane tax

 

[bungarm]

Thanks guys! I guess I should have used the 10mil in the first place...then I wouldn't have a worry. It's the fact that the place is rented that changes things; duty of care toward tenants etc and quite rightly too...I'll see what the assessor thinks, but I have this feeling that I will be changing it regardless <sigh> it's just the thought of lifting all those b***y floor boards again.....

Thanks again

Liz

 

[securespark]

If you're not willing to accept advice, even that which you don't want to hear, then there's no point posting, is there?

Guess whose cage got rattled !!

I was just a bit peturbed that bung did not want to consider cable replacement when this may have been necessary. "Tell me only what I want to hear" is not usually a good omen.... no offence, bung.

BTW, I am not in the least bit upset about the CH4 tax. In fact, GB himself is paying me handsomely to produce as much as I can. I f@rt into Jiffy bags and send them to No. 11.........

 

[AdamW]

I f@rt into Jiffy bags and send them to No. 11.........

I would do that, but I don't know the address

 

[securespark]

Just address it to Anthony at No 10 and it'll get there...

 

[2scoops0406]

Personally, I think it is to be applauded that concern has been shown as to whether or not the installation is safe.

 

[pipme]

I am beginning to think .. new house ... duct from near incomer to roof space for cables, suspended downstairs ceilings with overhead cabling fed from duct, lighting and ring ..... What lunacy to bury all cables in the wall and under carpeted / covered floorboards ... Such disruption to keep abreast of regs and desires etc ...
Might as well f@rt in a bag.

P