Power Cable to summer house

[dhutch]

I am vary torn, on one level I fully support the view that if you don't know what you are doing you shouldn't be messing with electrics, that's its hard to get enough information from scratch from a forum over the internet, and that its hard to get a picture for someones ability going the other way.

However on the flip side, the only things you need to terminate SWA are the terminations which you can get all over the shot, a stanley knife, baby hacksaw, and an adjustable spanner. I am a 'DIYer' if also a mechanical engineer, and have no issues at all with it.

Fixing SWA along a stout fence, or garden wall, is also fine.


Daniel

 

[EFLImpudence]

That's fair enough as far as you go but I maintain that to safely install power to an outbuilding you need to know 'everything' we do, therefore not a DIY job - no disrespect, I don't expect a DIYer to know that - so you should be asking a local electrician and do what he says rather than ask on a forum.

If others want to help and spell it all out then that is up to them.

 

[ericmark]

Since you should inspect and test and for the latter you will need low Ω meters, insulation testers, RCD testers, loop impedance testers and prospective short circuit current testers which will likely cost £75 even to hire and do need skill to use. Then is could be said there is no electrical job which can really be called a DIY job.

However we all know that most people can change a smashed socket for a new one without a problem. So we have to accept that people will DIY and try to instruct as to safe methods. The EZ150 plug in tester does not test like a full test set but in the main it is good enough to highlight most faults.

Using ohms law it is reasonably easy to calculate volt drop the hard part is working out what the resistance of the cable is. Our books however do give use the volt drop per meter per amp of cables and with a little maths one can work out the limits.

But even I would not want to dust off the slide rule and work out all the parameters from scratch. I sat down with java script and made myself a calculator so all I now need to do is feed in the data to get my answer and some of the members of this forum tested it and pointed out errors so reasonable sure it's giving correct results.

Using this I stated:-

At 30 meters 6mm sq will easy do 20 amp in fact still within limits at 32 amp using 4 mm sq then you drop to 20 amp and with 2.5 mm sq you drop to 13 amp so looking at 30 meters it is a question 13, 20 or 32 amp which in turn means 2.5, 4, or 6 mm cable.

If the poster is unable to select his cable from that I will agree it is reaching the point where you maybe need to question his ability but simply converting amps to watts is only possible if you know the relationship again I made a calculator fed up of starting up excel so 13A = 2.99kW, 20A = 4.6kW and 32A = 7.36kW so it is a simple addition problem. Just add all the items likely to be used together. Also it may help to realise that Watts and VA is in the main the same. Watts = VA x Power Factor Correction but in the main power factor is near to unity so can be ignored.

Giving advice as to using RCD protection and pointing out that there are laws which vary according to where you live which may require you to register the work and to point out going down the direct to LABC can cost more than getting a scheme member electrician to do the work is a valid comment. However I am sure most of my countrymen do not pay the council the £100 plus vat required to fit an outside socket. The fact the minimum charge is so high means most people ignore it.

To my mind not to help the DIY guy means he is more likely to make errors. So we should give them all the help we can in the hope we reduce accidents.