Electricity supply

[Brooklynodog]

I want to run an electric cable to my polytunnel to power a heater. I was told to run a 13 amp cable in an old hose for protection. I have tried to push the cable up the hose (need about 30ft) can only get it up so far, then it jams. Any suggestions please forum?

[Belinda]

A small screw tied to a very long piece of thin string and a second floor window might do the trick.

Or alternatively cut the hose lengthwise, put the cable inside, then use gaffa tape to seal.

[Geoff]

Are you trying to use cable like you attach to a plug or grey twin and earth? The grey stuff usually goes through OK with a bit of the silicone you use for plastic pipe joints.

[Vegman]

May I suggest that you be careful here please. Ideally you should use an amoured cable which can be buried directly in the soil and will resist a blow with a spade. Or buy some plastic conduit from B&Q which is about 2.5m long plus sleeve joints and about 20mm dia. insert in that.

If your runing the cable directly from your consummer unit make sure it has a cicuit breaker fitted [detects a short] so you dont get electricuted if there is damge to the cable.

If your taking it from a socket then fit one there. Fit an isolator also so that it can be disconnected say when washing etc.

I would ask someone who you may know, the best way to tackle this before you start.

There is usually a sparky on call at a B&Q warehouse if you have one near.

[John]

Hello Brooklynog
Another way of doing this would be to use the rigid plastic pipe that's used for overflow pipes (can't remember the diameter - about 3/4 in?). You would need several lengths but the push fit connectors are simple to use and it will be easier to work in the 3-4m lengths that I think this stuff comes in.

Personally from a safety point of view I would consider getting the armoured cable that's sold specially for this sort of work.

John

[Chantal]

It's worth having a look at a previous thread

viewtopic.php?t=797&highlight=electrician

as there a lot of regulations out there which apply to what you're doing.

[Brooklynodog]

Thank you Chantal, have read and inwardly digested. However, what I want to do is no more than an extension lead as one would use with a lawn mower. Then i can put my frost guard heater on only when likely to be cold. Presumably this is a temporary measure under the regs?

[Chantal]

I'm the wrong person to ask, Piglet is the authority on this, you could send him a PM. I just recalled his posting and I know it's important.

When I had power from my garage to my greenhouse, this was just, in effect, an extension but I had to have circuit breakers and all sorts and this was BEFORE the Part P regs came in. It's worth checking out

[chenkittie]

You can do the trick by putting the wire inside the hose or by using an armored cable. This would prevent unnecessary things that might happen. You can also use a circuit breaker for safer electrical system.

[Tony Hague]

This is one of the problems with Part P. Make it too difficult and expensive to do it properly, and people will do a (perfectly legal but not as safe) bodge instead.

The hose will not offer much protection, but if you are going to do it, get the hose straight, an assistant at the other end to hold it. Take a thin, stiff wire, e.g. plastic coated steel garden wire, fold the first inch back on itself to prevent the cut end of the wire snagging on the walls of the hose, thread that through first and use that to pull the actual cable through. Jiggling the hose may help. There are proper tools to replace the thin, stiff wire if you do it often !

Whatever you do, make sure you use an ELCB for any outdoor electrics.

[JohnN]

Fishing tackle shops sell reels of very fine monofilament line that slides through anything, and you can get a small streamlined weight there, too.
John N

[Stephen]

In my opinion:
if you are going to pack it away each time (or at least regularly) as you suggest by comparing it to the extension for the mower, then just get the right length of flex (ask for "arctic blue" which stays more flexible in the cold) and make up a line with an RCD (Residual Current Device) integrated into the plug. ...And pack it away regularly.
If you are going to run it out in the autumn, leave it for 3 or four moths, then pack it away, you really should make sure that it has more physical protection than a bit of hosepipe (as well as an RCD).
Do ensure that there is absolutely no chance that it is left in place for someone else to damage...

The regs are there for your (and everyone elses) protection, and I don't want to undermine anyone else (they probably know more than me!) but you should think about why they are written in the way that they are (even if they make little allowance for semi-temporary conditions such as this).