More Garden Stuff

[beebolbod]

Hello,

I'm currently re-training to become an electrician (in a pretty roundabout way) and have done a part p course, so i have a fairly ok understanding of that, but i currently lack experience.

A friend has asked me to 'do' his garden and as i'm trying to learn i thought it would be good to use this and a couple of other projects i have on the go, to get the relevant experience (or start to at least), with a view to getting into NAPIT or NIC eventually so i can self cert.

I'm a consultant engineer at the moment (in telecomms) so i do have fundamental knowledge of electrics etc but like i said, i'm working on the actual experience which is currently lacking (you'll see how much in a minute).

I'm awaiting a Megger 1552 to start my testing (i'll test anything and everything i can to get good at that before any work is done) but in the meantime i could use a bit of help with a few things....

Here's the brief....

He has a requirement for sockets in the greenhouse, a socket by a decking platform in the middle of the garden and a socket in the shed.
He also wants 2 fountains, some pillar lights and wall lights and some small uplighters around the edge.
The post and wall lights need to be dimmable, the rest not, and these all need to be controlled by switches inside the house. Everything must be buried (connections to fountains/lights etc) so no simple 'plugging in to outside sockets'.

Here's my thinking....

6A MCB to 1.5mm SWA to run the lights with the same cable going back to the switches. I'll have to split the circuit somewhere to provide individual control of the 2 sets (perimeter uplighters and pillar/walls) - question to follow about this.

32A RCD to 6mm SWA to the GH, a spur to the first fountain, a spur for the other larger fountain and then into the shed.
50m of cable *should* do it (i'm still only thinking about all this so far - nothing measured or drawn yet).

Here's my questions....

1. Can i terminate the SWA into relevant IP rated JBs and then connect up the lights/foutnains etc from them? How is this done? I can terminate the SWA but i mean how to connect each light as the SWA needs to go to a box i thought?

2. Do i use the cable sheath for the earth and take that from the CU inside?

3. Can i do the spurs? Is that do-able/allowed/sensible/easiest?

4. Am i close?

Many thanks and apologies for length.

 

[Chivers7]

http://www.tlc-direct.co.uk/Products/LB9065.html Resin filled should do the trick

 

[comms]

He has a requirement for sockets in the greenhouse

If the green house is metal framed or internal staging is metal you'll need bonding.

6A MCB to 1.5mm SWA to run the lights with the same cable going back to the switches. I'll have to split the circuit somewhere to provide individual control of the 2 sets (perimeter uplighters and pillar/walls) - question to follow about this.

Take a look at this it migt save some time for you.
http://www.tlc-direct.co.uk/Technical/DataSheets/EasySwitch/LMESR4.pdf

32A RCD to 6mm SWA to the GH

Why not goto the shed with the 6mm or 10mm install a small cu, then run smaller csa swa to other circuits ?

1. Can i terminate the SWA into relevant IP rated JBs and then connect up the lights/foutnains etc from them? How is this done? I can terminate the SWA but i mean how to connect each light as the SWA needs to go to a box i thought?

Use http://www.tlc-direct.co.uk/Products/LB9045.html
with http://www.tlc-direct.co.uk/Products/PRPEN20.html to keep the IP integrity of the enclosure when terminating swa (saves using he banjo with nut/bolt)
not forgetting http://www.tlc-direct.co.uk/Products/EK252B.html for the load flex.

2. Do i use the cable sheath for the earth and take that from the CU inside?

You can do if you know what csa the armour is (I've got a handy link for this somewhere), or just run 3 core & use one core as earth + the armour.
You could come off the house cu or split the meter tails with henleys, tails into switch fuse then swa out to shed, where you'll install a nice shiney cu on a TT system with mainswitch/rcd or use rcbo's for circuits.

3. Can i do the spurs? Is that do-able/allowed/sensible/easiest?

I'd run a dedicated circuit for the fountains, Plus you can then isolate them at winter or if there is a problem with them in the future without having to isolate the green house circuit.

4. Am i close?

Depends on how others would undertake the work

 

[Cremeegg]

Generally agree with Comms good advice - the piranahs are wonderful.

As a general comment on cable sizes I presume you have checked the required loads - greenhouse heaters can take a lot - and the voltage drops. Always oversize to allow for expansion - saves much digging later on.

I'd always use 3 core and dont forget to earth the armour as well via the piranah; and plenty of "cable below" tape to keep the NAPIT man happy.

 

[beebolbod]

Thanks for the advice. Seems i wasn't a million miles away in my thinking. I dont have the exact load yet and i haven't checked for what drop to expect either - yet. I dont think heaters are going in the GH but i did think of 10mm for future proofing just in case.

From what you say, it looks as though i'll have to go to a mini CU in the shed as those boxes dont take 6 or 10mm swa (by the looks of the specs).
Can you get boxes that do?

I want to avoid the extra CU at all costs really. It's extra work i could do without as we're trying to do this cheaply and with serious time pressures (i'm currently doing a complete rewire on my own house too).

 

[breezer]

Terminate the swa in a metal adaptable box, its easier and unlike plastic doesnt warp / twist