Shower Cable Selector

[ZetTimC]

The cable ratings panel on the selector page could do with a little modification . . .

6mm Cable is OK up to 40A
10mm Cable to 53A

If you read the page as I did - you could end up thinking that 6mm cable is OK for 52A - which it isn't

Otherwise a very useful site

 

[AnonymousImport]

sadley the shower cable rating shown does not meet IEE regs and is greatly under sized

 

[AnonymousImport]

Also as 6mm cable will be ok for 40amp at less thon say 20/25metre run of cable then 10mm must be used for 40amp on longer runs. Basically the longer the run of cable the more volt-drop so bigger cable needed

 

[AnonymousImport]

The current IEE wiring regulations allow up to 46 amps for a 6mm two core, single-phase cable. This is where it is open and clipped direct to a surface and not enclosed in conduit or trunking. If enclosed in conduit or trunking this value is reduced to 38 amps. Where the cable is enclosed in conduit and also in an insulated wall, etc. this is further reduced to 32 amps. Volt drop must also be taken into consideration but this will only be important on long runs of cable. In a normal sized house, where the shower is no more than 10 to 15 metres away from the fusebox this will not be a factor.

 

[pc]

This is my first use of this site.

The calclator suggests my 9.5KW shower would take 40 amps and suggests "6 to 10 mm" cable. As the options are 6mm or 10mm, I need more guidance as to which I should use. The cable will be routed primarily in the open over joists in the loft and will only be enclosed for a metre or 2 in the uninsulated stud partition wall in which the shower and switch are installed. I estimate the total run will be approx 15m, but what are the factors that I must consider when choosing 6mm or 10mm?

In addition, my consumer unit is an older type which has re-wireable fuses. Would a simple 45 amp fuse in a dedicated terminal be acceptable or do IEE regs require additional devices (RCD, MCB etc).

 

[breezer]

if in doubt have the bigger cable, saves you money in the long run incase you ever have a bigger shower at a later date.

as for an rcd it would be a good idea, why not get the whole consumers unit changed they don't cost that much

 

[alexnic]

Use the cable selector on the following website ...tad more accurate!

http://www.tlc-direct.co.uk/Technical/index.html

As Breezer says.... a new split load CU is relatively inexpensive these days.

£34.50 + VAT will get you this and that includes the RCD and Main Switch + the cost of the MCBs (£4.50 = VAT)

 

[Scoby_Beasley]

Please enlighten me breezer, how does a split c/u actually work ? Are some covered by the rcd and the other side not ? Love to know.

 

[alexnic]

Yes .... you can usually determine which circuits you like to be covered by the RCD eg. Ring mains, cooker, outside sockets, shower etc. and you would tend to have the lighting, possibly Central Heating, bell transformer or whatever not covered by the RCD.

Some Split Load CU's are predetermined ie 5 from RCD and 5 from main switch whereas others can be shuffled about to suit yourself

 

[Scoby_Beasley]

Thanks for the reply alexnic, I now see the logic .
It's a royal pain in the a++e in our house when a bulb blows downstairs and trips the mcb !!

 

[masona]

See below!

 

[masona]

Can you get lockable key type or padlock on a CU door cover to stop anyone accidentally switching the mains back on if I'm working on the electirc somewhere.In the old days I used to pull the fuse out and put it in my pocket!

 

[pc]

Can somebody address the original topic of shower cable selection and start a new one on sonsumer units!

 

[breezer]

my first post answered your question, which is why no one else said anything

 

[pc]

For breezer

You did not answer the questions at all. I never intend to fit a larger shower than 9.5KW. I do not want to use 10mm if 6mm will do. I do not want to totally rewire/replace the fusebox. I want to fit only what is NECESSARY to comply with regulations.