Ask The Trades - Print Page

Ask The Trades
https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Electrical Questions >> Shower Cable/Fuse size https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1231584216 Message started by side-show-bob55 on Jan 10^th, 2009, 10:43am

Title: Shower Cable/Fuse size
Post by side-show-bob55 on Jan 10^th, 2009, 10:43am

Hi all

I have a 7Kw shower which has died, it looks like it is wired in 6mm to a 30Amp fuse. What size shower can i replace it with? I have seen a 9.5Kw on sale but iam unsure as to wether the cable and/or fuse will be up to it.

Cheers
Rob

Title: Re: Shower Cable/Fuse size
Post by cosbycarl on Jan 10^th, 2009, 12:10pm

A 9.5kw shower would need the supply cable changing to a 10mm and a 45a fuse.

Title: Re: Shower Cable/Fuse size
Post by The_Trician on Jan 10^th, 2009, 9:04pm

Replace with either one of the same rating, or with one with a max rating of 8.5KW, and you won't have to replace the cable etc.

I've seen showers rated up to 11.5KW, and beleive me, the water ain't any hotter!

But your electricity bill be will larger!

TT

Title: Re: Shower Cable/Fuse size
Post by Lectrician on Jan 10^th, 2009, 10:03pm

High wattage showers are good in conditions like this cold snap.

A larger shower will give a better temperature of water in days where the water coming out of th pipes in the ground in very cold.

During the summer months, or less harsh conditions, 8.5 is fine.

Title: Re: Shower Cable/Fuse size
Post by cosbycarl on Jan 10^th, 2009, 10:29pm

6mm, ref method 100 has a ccc of 34a, ref meth 101 has a ccc of 27a and clipped direct is 47a.

How do we know if there isnt insulation covering the 6mm in the roof and how thick the insulation is too, i doubt the cable is just clipped direct. Also, i read the osg and it states no diversity allowable for a thermostatically controlled heater, which a shower is. So 8.5kw/230v = 37a rounded up, even if 240v applied then its still 35.4a?

You know way more than me TT, but what your saying doesnt add up? Maybe ive read it wrong or took whats written down the wrong way?

Title: Re: Shower Cable/Fuse size
Post by Zambezi on Jan 10^th, 2009, 10:38pm

CC you are right TT does not know what is there i.e. insulation, nails through cable etc. I think he is going along the theory that if there was a shower there before then there is no reason why you should not be able to run a shower of a similar size without a problem. Showers don't normally run for a long time so chances of the cable heating up to a dangerous level are slim. Length of run is not normally very much either so... you get the picture.

Title: Re: Shower Cable/Fuse size
Post by LSpark on Jan 11^th, 2009, 1:32am

I don't think CC is taking into account the factor of fusing from a 3036 or 1361 fuse, compared to say a 60898 type-b circuit breaker.

Title: Re: Shower Cable/Fuse size
Post by Lectrician on Jan 11^th, 2009, 10:40am

The real answer is that a 30amp fuse will support upto a 6.9kW shower, as to if the cable is suitable, it does depend in the install method.

The install method MAY allow for a larger OCPD to be used in place of the 30amp, but this needs to be assessed.