Electric shower in outbuilding

[shedhead]

Hi,
I have a garage at the bottom of my garden which I have put power in. I wired the supply using 6mm cable feed through plastic conduit. I took power from a 13amp socket in house, run through a fused spur. However I wish to install a 7.5 kW shower into garage for my dogs. They have long shaggy coats and need washed before they get groomed. The distance from house to garage is about 30m away.
My intention is to connect to cable that feeds my shower in my house, which has all the correct protection, i.e. 40amp trip switch. I want to catch a main supply in loft space at ceiling switch above bathroom. Then connect up with cable as it leaves house this will add further 10m of 6m cable. In theory garage supply will come straight from consumer unit.
Total length from consumer unit to shower in garage about 50m. I think I can hear the groans from all the sparks reading this. If this is too long a run for cable size, would I get away with replacing the last part, i.e. 30m run from house to garage with 10m cable.
I will feed shower with garden hose, I feel that the water pressure is fine to run shower. The shower its self will be free from frost and will be disconnected both water and electricity when not in use. I will fit a circuit breaker next to shower. I estimate shower will be used once for each dog, duration about 15 minutes each every 10 weeks as this is how often they will need washed before they get groomed. The temperature, even in winter will only need to be tepid as the dogs swim in sea all year round.

 

[streetlighter]

Think you will need to run a proper submain cable running to the garage from a spare fuseway in the main consumer unit. Considering the size of the load and the lenght of the run you really need to get a qualified Electrician to carry out the installation.

By my calculation you will need a 16mm SWA at least

 

[shedhead]

Thanks for the bad news Streetlighter.

If i were to wire straight from consumer unit to garage length would drop to about 35 - 40m would i get away with using 10mm twin & earth?
Is there nothing else i can use to heat water to tepid temp, that uses less juice like an old geyser type heater.
What does SWA mean?
The cost of 16mm cable at the length i need is well over £120 for cable alone. HELP!!

 

[breezer]

The cost of 16mm cable at the length i need is well over £120 for cable alone. HELP!!

so?

if you want to do the job you will have to do it proplerly, i doubt it will take that long to get your money back.

you could also opt for a lesser kw shower

and swa is Steel Wire Armoured (it protects the cable)

 

[pcboffinuk]

Streetlighter is right I'm afraid shedhead, you can play with the figures yourself here

I should have thought you could get away with a lower rated shower, 5kw or less should let you use 6mm SWA (much better than standard pvc cable even through a conduit).

Just thinking out of the box a little, not sure if its a viable option where you are but a solar heated shower might be worth investigating? Or perhaps an immersion heater in the shed, depending on how big it is.

Alternatively, you might try the plumbing forum to see how practical it would be to pipe hot water that distance rather than power - perhaps with a shower pump at the house end?

Afraid whichever size cable you ended up using on the electrical route Part P will mean you would have to get a registered spark in, or notify to LABC and pay their fee.

 

[JohnD]

agree, an instant shower is going to need a lot of power, I wonder if there is some kind of Camping water heater that might run off bottled gas?

A stored water heater (like a kettle or an immersion heater or an under-sink heater) is always lighter on power as it can heat the water much slower than you use it, and they usually take less than 15A. With good insulation heat loss is amazingly slow (e.g. will stay hot overnight) and any lost heat will help prevent your shed from freezing in winter.

It might even be simpler to run a pipe to the hot taps in the house

 

[shedhead]

Thanks to everyone for there replies. I think i will need to contact a spark if i am using shower. I would like to know more about using a immersion heater, to see if this would mean i could get warm water with my 6mm cable?????????. Or the camping heater.
Thanks again for giving me your advice and experience.

 

[Steve]

You say you're using a hosepipe to feed the electric shower. I have a better idea. Connect the hosepipe to the electric shower in the house! Or a mixer tap! wash the dogs in the bath! wash them in the shower! Take them to the nearest lake! Wash them with cold water!