11kw shower cable size?

[Chris14]

For 11kw shower what cable size is required for 15m run?

 

[Tim]

What reference method?

 

[telectrix]

6mm clipped direct just on the limit, but you'd need a OCPD of 50A, so 6mm is out of the equation. 10mm on a 50AMCB is your only choice.

 

[Outspoken]

11kW @ 230V = 47.8A
11kW @ 240V = 45.8A

Whichever way you look at it 6mm² will not be sufficient because the CPD will need to be a 50A MCB as Tel has already stated.

You need to state how the cable is run however, because the environment the cable is installed in dictates how much it is de-rated by, and you could end up with 16mm² if your running it in fully insulated spaces or in an environment subjected to external heating.

 

[Guest55]

good job its not 9.5kw , thats just asking for heaps of trouble.

 

[oldtimer]

GROUNDHOG DAY ? or is it just me ?

 

[Guest55]

i say 6mm.........
you say 10mm.........
i say potatoe.........
you say potaytow.........
lets call the whole job off , lol.

 

[telectrix]

more like apocolypse now. wait for the 10kW cooker cable questions.

 

[pennywise]

2, 4mm in parallel

 

[Outspoken]

Guys, what about this kiddy...

Redwing 12kW Shower

Personally I say 16mm² will be sufficient on a 286m run, but the Regs work it out to be a 120mm²...anyone any thoughts...Muhahahahahaha

 

[monkeyelectric]

Who in their right mind would want an 11kw shower?

 

[monkeyelectric]

Guys, what about this kiddy...

Redwing 12kW Shower

Personally I say 16mm² will be sufficient on a 286m run, but the Regs work it out to be a 120mm²...anyone any thoughts...Muhahahahahaha

I got asked to install one of those once and his "mate" who was an electrician but out of the country at the time said it could be spurred off the ring i couldn't see a problem and i only had 1.5 with me at the time so i used that, do you think it'll be ok? I did change the mcb to a 50A too cos it kept tripping that poxy 32A

 

[Guest55]

anything above 10.5kw is a complete waste of time......
why ?
cos its unlikely that you'll have water pressure high enough in an upstairs bathroom to match the flow rate available from the heating element.

thats todays technical insight out the way , its downhill from here on.
;-)

 

[Geordie Spark]

GROUNDHOG DAY ? or is it just me ?

Everyday is Groundhog day.

 

[chopper76]

Some of these showers are turning mental, it's got to get to a point when you can't really heat the water much quicker under standard water pressure?

 

[telectrix]

anyone living next door to the jones's who have a 10kW shower. just plain snobbery.

 

[oldtimer]

Christmas day mum has the cooker going full pelt and dad decides to make her a cup of tea and a slice of toast and at the same time daughter steps into the 11kw shower thats when you find out if your 60A DNO fuse will be ok lol

 

[telectrix]

you forgot the porridge in the 3kW microwave.

 

[Guest55]

you forgot the porridge in the 3kW microwave.

porridge on xmas day ?
are you in prison ?
lol ;-)

 

[oldtimer]

porridge on xmas day ?
are you in prison ?
lol ;-)

Na in prison they get the full christmas lunch but the Warders have to make do with the sannies they bring in as told to me by a warden friend

 

[Geordie Spark]

porridge on xmas day ?
are you in prison ?
lol ;-)

Judging by some of his posts on this board he damn' well should be !!!

 

[Darkwood]

The OP occupation is stated as Gas so at a guess he's either got bad wind or he's a plumber and with all due respect to the kind nature of this forum he really needs to get a competent electrician on site as oppose to taking a few tips off here and doing it himself, any missed info could be vital to the safety of this install and he clearly hasn't any electrical experience with the basic form of his question...... do the OP a favour boys and recommend a sparkie to weigh it up you haven't spent years training and learning all this to do all the calcs for a DIYer /plumber working outside his trade.

 

[MDJ]

For 11kw shower what cable size is required for 15m run?

depends on the cable type, not very big if MICC is run in :rolleyes2:

 

[Geordie Spark]

Na in prison they get the full christmas lunch but the Warders have to make do with the sannies they bring in as told to me by a warden friend

He'll probably find his sarnies are better than the "full Christmas lunch".

 

[Octopus]

Dare I venture to suggest getting a sparky in?

Or has the OP gone away?????????

 

[Thefailsafe2012]

Dare I venture to suggest getting a sparky in?

Or has the OP gone away?????????

Praps he's potting some Micc as we speak!

 

[Outspoken]

anyone living next door to the jones's who have a 10kW shower. just plain snobbery.

I have a 43.9kW shower...well actually it's a 150,000 BTU Potterton Boiler...That is only wired on a 1.5mm² flex from a 13A spur, works fine!! (I think the gas connection helps though!)

 

[Outspoken]

Dare I venture to suggest getting a sparky in?

Or has the OP gone away?????????

I think I found him..

 

[Geordie Spark]

I have a 43.9kW shower...well actually it's a 150,000 BTU Potterton Boiler...That is only wired on a 1.5mm² flex from a 13A spur, works fine!! (I think the gas connection helps though!)

It will do more than work fine ... It'll knock the spots off any domestic electric shower any day of the week, any time of the year.

 

[Engineer54]

2, 4mm in parallel

What, ....and then have people telling you, that you need to apply a grouping factor!! lol!!

 

[telectrix]

Group showers. Like it. AND THE GROPING FACTOR.

 

[GLENNSPARK]

Who in their right mind would want an 11kw shower?

greasy monkeys perhaps:joker:

 

[Mr Mark Sparks]

Who in their right mind would want an 11kw shower?

The same loony who surprises you with an 11 kw range oven with induction hob, warming draw twin oven and grill after saying its a double oven and gas hob......

 

[Stroppy]

At least then you can fry bacon on the cable as a bonus.

 

[Rockingit]

The same loony who surprises you with an 11 kw range oven with induction hob, warming draw twin oven and grill after saying its a double oven and gas hob......

Bit of 6mm and a 32 it is, then.

 

[Mr Mark Sparks]

Bit of 6mm and a 32 it is, then.

Indeed it still is fingers crossed Xmas day.

 

[monkeyelectric]

greasy monkeys perhaps:joker:

A 9kw is just as good at getting the grease out of a monkeys fur and i would know

 

[kingeri]

My 8kw serves me well, usually use it on half power setting as well. Still miss the power shower from the old house though. And my 8kw is on 10mm and a 32a breaker for info

 

[Knobhead]

I think I found him..

View attachment 18892

Oi!
Who said you could use my photograph!

It was a bad hair day.

 

[flyinghigher201]

lol one of the things ive been doing at college is cable calcs. very interesting

 

[alanl]

6mm clipped direct just on the limit, but you'd need a OCPD of 50A, so 6mm is out of the equation.

Why?
433.3.1 (ii)
A shower is a fixed resitive load, so very unlikely to be subject to overload current apart from a fault.
It has fault protection via the RCD (and the 50A CB), any fault will be cleared in less than 0.3 seconds that the RCD takes, so a 50, or even 100A CB will be compliant.
(of course so long as cable length, Zs, grouping/reference all comply too)

 

[telectrix]

the shower is 47A so the OCPD needs to be >47A but less than the Iz of the cable. so a 50A MCB. this means that the cable Iz must be > 50A so it's got to be 10mm.


what's the RCD got to do with overload protection?

 

[alanl]

No, sorry, you are wrong.
It is a fixed resistive load, so does not need overload protection, it must have fault protection, which the RCD will provide.

 

[telectrix]

nothing to do with the type of load. it's the cable that needs overload protection. what's the RCD going to do in the case of a short circuit L-N?

 

[alanl]

433.3.1
There is no need for circuit protection if the load is unlikely to carry overload currents. A shower will not overload unless it has a fault. No-one is likely to fix the circuit directly to the outgoing RCD terminals, so fixing it to a CB rated higher than the current carrying capacity of the cable is quite acceptable in such circumstances, so long as the cable can carry the current of the appliance.
A L-N fault will cause many hundreds of amps to flow (in most installations), meaning any CB fitted, whether 50 or 100A will trip virtually instantly. It is only in fault conditions that a L-N short will occur.
Hence it is compliant to run a cable with a 47A capacity, feeding a 45A fixed load appliance, fed via a 50A CB, as there will be fault protection, both via any CB fitted, and via the RCD which will have to be fotted in any domestic premises. There will be no overload protection, but that isnt required, as stated in 433.3.1.

 

[Toonlad]

Raises eyebrow........mmmmmmmmmmmm........:thinking2:

 

[44ALLAN]

Raises eyebrow........mmmmmmmmmmmm........:thinking2:

Lol.

Wheres me books....................................

 

[Toonlad]

mines in front of me. Im thinking BS1361 60/80 amp fuse now

 

[telectrix]

i'll accept that if , and only if, the circuit Zs is sufficiently low enough to cause the OCPD to trip within the required time. e.g. < 0.37ohms for a 100A type B MCB. say the Ze was 0.2, then your R1+R2 for the 6mm cable would need to be < 0.17, i.e a circuit length of not more than 15m. if the Ze was > 0.3ohms, then you're stuffed.

 

[44ALLAN]

mines in front of me. Im thinking BS1361 60/80 amp fuse now

I'm thinking gravity fed shower off the boiler sod all this palava :shocked3: