Outdoor Electrics

[fairly-competent]

I know I'm being quite ambitious here but I want to install a number of outdoor circuits (I would probably need to remortgage to get this lot done by a pro):
1. 20-30 decking lights 12V with outdoor transformer, 3-4 pond lights 12V with outdoor transformer and a set of 300-400 outdoor fairy lights 240v.
Probably no more than 100W in total and I want to be able to switch these all on from a light switch inside the house.
2. A 500W 240V security light with separate indoor switch.
3. Pond pump and UV filter (100W 240V) on 24 hours a day.
4. A 240V diverter valve connected to an indoor timer which will divert the water to a waterfall during the day but directly into the pond at night.
5. Two double outdoor sockets which can also be switched off from inside the house.
6. Four 1300W 240V halogen patio heaters connected in pairs to two Horstmann E30 Electrisaver timers.
I know this lot will need to be protected by a 30mA RCD. Should each circuit have its own MCB or could a few circuits run off one MCB? What rating should each MCB have? - I have a pretty good idea but would like confirmation. I have 2 spare fuseways on the CU but the CU is not RCD protected so do I get a 2nd CU with RCD and connect it to a spare fuseway on the main CU or replace the existing CU for a split load CU?
No cable run will be more than 15 metres and no cables will be buried - they will either go through the wall from inside straight into the appliance or socket box or will be attached to the wall or the underside of the decking. What size cables do I need to use? Will 4mm be sufficient for the heaters, 2.5mm for the sockets, 1.5mm for everything else? Do I have to use SWA outside or will T&E in conduit be fine? Hope somebody can help - I just don't seem to be able to find much info on outdoor electrics.

Thanks.

 

[breezer]

1) plug them in

2) take it off upstairs ring (must you really have 500w)

3) swa cable

4) think again.

it would need to be either weather proof or protected from the elements, why not supply the waterfall from your filter / uv.

5) why

6) get gas

you dont run T & E in conduit

outside cable should be swa and buried, it will look ? (because you wont see it, conduit will look ergh

 

[Taylortwocities]

you dont run T & E in conduit

Not even steel conduit?

 

[fairly-competent]

Thanks for reply.

1) plug them in

So I could plug them all into weatherproof sockets switched from a DP switch inside the house?

2) take it off upstairs ring (must you really have 500w)

OK, maybe 500w is a little excessive.

3) swa cable... outside cable should be swa and buried, it will look ? (because you wont see it, conduit will look ergh

You wouldn't see it anyway because it would be attached to the underside of the raised decking. It will be difficult to bury because the decking sits on a solid concrete base. BTW, pond is a raised formal brick pond adjoining the decking, not a hole in the garden.

4) think again. it would need to be either weather proof or protected from the elements, why not supply the waterfall from your filter / uv.

The plan is to put the diverter in a weatherproof shelter between the output from the filter and the inflow to the waterfall/pond. I could have used two separate pumps, one for the filter and one for the waterfall but I figured this would use twice the electricity when both were in operation.

5) why

For convenience (and so no-one can nick our electric while we are away on holiday).

6) get gas

Calor gas patio heaters are smelly, take up lots of space on a small deck or table, require refills (which always run out just when you need them) and are apparently bad news for the ozone.

Also any advice you can give re cables, MCB's and procedure with CU would be much appreciated. Could I run the heaters off one 32A circuit and everything else off another 32A (with FCU spurs for the lower rated stuff)?

Thanks.

 

[breezer]

Taylortwocities i never said you cant run t&e in conduit, its just one of the things you dont do


fairly-competent

1) yes if you could find a suitble socket.

some light strings are supplied by a "wall wart" using a wall wart would not enable the socket to remain weather proof simple solution get lights with no wall wart (not easy if you buy a ready made set)

2) yes it is

3) how you going to do that then? (unless there is enough room for you to get under the decking to fix it )

4) use two pumps
less hassle, no additional wiring (not if you have a valve as the valve will want wiring) get decent pumps, they do use less electricity

a 3 way valve will be around £50 (i just googled) it only accepts 22mm copper pipe, it can be done, (i too thought about that years ago) but you will have to buy additional fittings to connect the copper pipe to your pvc pipe from the pump etc

1 extra pump will be less hassle and is either on or off, unlike a valve


5) i doubt if any one will want to pinch your electricity, not as if they can put it in a box and take it away, an extension lead going into next doors house will be a bit of a give away

6) will you be basting people with oil?

from the sounds of it 4 heaters is a bit much, but it really does depend on how big an area you will be heating.

could always wear a jumper if you are worried about the enviroment.

I think this one needs a separte post (once you have decided what to do)


I comend you on your ideas. and well done for asking first.

but do you realise how much wall you are going to take up with all these switches?

You can not use a couple of ordianiry 3 gang switches becuse of the current they will have to switch.

You are going to have to use either single gang double pole switches or your best option would be grid switches, you can even get grid fuse holders (to supply everything else, you could even have grid neons to indicate what is on, but the more "bits" you have the bigger the grid switch will be.

You will probably end up having a dedicated switch room / cupboard. its not as bad as it sounds but it will allow you to do everything you want.

Its quite common for koi keepers

 

[Steve]

FFS heating outside - FOUR heaters?!?!?! TIMER??? You mean you're going to leave them all on on a timer??? Even when there's nobody outside to heat?????

You'll have to remortgage to afford the electric bills mate. Go and buy a jumper. The next clearance sale is on now. Electric heaters are worse news for "ozone" as you put it. The losses in the distribution network make electric worse for the environment.

If you must have a heater have ONE and put it on a PIR sensor AND a thermostat (so it only comes on when the temp is below, say, 15, and when theres someone stood there to heat)

 

[breezer]

i wouldnt opt for the pir, the pir may see the heat from the heater and never turn off

but i whole heartedly agree with crafty, regarding the heaters in the first place, i did say

6) will you be basting people with oil?

from the sounds of it 4 heaters is a bit much, but it really does depend on how big an area you will be heating.

could always wear a jumper if you are worried about the enviroment.

 

[fairly-competent]

1. Light string I have in mind is 240V so no wall wart to worry about:
http://www.lights4fun.co.uk/outdoor/wedding-lights/5szz497p.asp

3. The decking is about 2 feet above the ground. It measures 3m X 14m and as most halogen patio heaters cover 3m X 3m, I will need 4 (it gets bloody cold up here in Newcastle in the evenings but maybe I'll just get one or two). Crafty, the timer I have specified is an immersion heater timer which switches off automatically when you forget (it can't switch on automatically)
http://www.horstmann.co.uk/water-heating.asp

With a little repositioning of things, I am now able to put all the outdoor connections on the house wall, so no need to run cables under decking (apart from LV lighting cable and pond pump/filter rubber flex)

 

[wiggles]

(it gets b****y cold up here in Newcastle in the evenings but maybe I'll just get one or two).

When it gets cold, I go indoors. When it gets hot, I go outdoors.

Crafty, the timer I have specified is an immersion heater timer which switches off automatically when you forget (it can't switch on automatically)

That's a good idea. You could also use switches with neon's on them to remind you that you have them switched on.

 

[fairly-competent]

OK, OK, I know everybody is laughing at me for wanting to install outdoor heaters - she who must be obeyed wants them so that, as they say, is that.

 

[CallEdsFirst]

I think it sounds like it might be a lovely garden and the guy is here for solutions, not for people to tell him he can't have what he wants, even if a little misguided!

As an aside, am I right in thinking that Part L (Hooray, a part other than Part P!) restricts single fittings outdoors to 150w or less? Is that new homes only?

 

[breezer]

new one on me

 

[CallEdsFirst]

Yep I found it, but it is for new dwellings only, where building started after October 2006. Its the same building regs that led to the introduction of low energy pendants (1 in every 3 in a house) that take PL/CFL lamps. One for all you house bashers!

 

[fairly-competent]

OK, I've managed to convince my wife that we only need one patio heater (not 4). I could still do with some advice on the best way to wire all this up. Should I just create a new ring main for the outdoor electrics on a spare fuseway on the consumer unit using a 32A 30mA RCBO with a 6A spur for the lighting? Or should I use the spare fuseway to feed a separate consumer unit with 30mA RCD, 16A and 6A MCB?

 

[breezer]

your choice

my thoughts.

mini cu good idea where to put it still need switches to turn stuff on / off where will these go