SWA size recommendation

[JonoPashley]

Try www.discount-electrical.com for cable if your spark cant get it cheaper, if you go here http://www.gadsolutions.biz/regulations/swa-as-the-cpc?start=1 you can learn a bit about using the armor as a earth.

 

[Escos]

Thanks JP

That is quite a bit cheaper.!
Until i can get a sparky out, what would you recommend regarding cable size 16mm or 25mm.? Im now thinking of going for 25mm just to be sure it will handle the load.

 

[JonoPashley]

XLPE 2 core SWA in 16mm will hold 110A clipped direct, 99A or so buried in the ground.

 

[bernardgreen]

You need to considered the start up currents of the compressor when calculating the voltage drop along the cable.

The current taken before the accelerating motor reaches normal operating speed can be several times the normal running current. So the voltage drop along the cable can be several times the voltage drop when running at normal speed.

If the voltage to the motor is reduced during start up then the time before reaching normal speed is lengthened. This prolonged period with higher than normal current can result in the motor overheating.

Check with the manufacturers about minimum voltages during start up.

 

[ban-all-sheds]

To Ban all Sheds; I never said i "new it all".

I know - I was just giving my opinion that you didn't know enough to be taking this job on.

I proposed to terminate the swa into a galvanised adaptable box.

So you were going to have the galvanised box at the potential of the incoming supply earth, but not export that to the garage installation, which would have the local ground as it's earth.

Do you see any problems with that?

I will be getting an electrician to do the work, iwas just thinking of laying the cable myself and getting it inside both buildings.

There should be no problem with that - there aren't many electricians who wish they could spend more time digging trenches.

BUT - you must let the electrician be in charge, and make all the decisions on cable route and depth, trench bed preparation etc. You must leave him to do the terminations. You must leave him to do the design, including cable size and the earth export issues.

He is the one who will have to sign documents to say that he did all the work, so he must be completely in charge of all decisions, and completely in charge of any grunt work that you do.

I have worked with a friend who is a sparky, unfortunately he has now emigrated.

So you won't be using him, then...

He did a lot of factory electrics

He may not have been registered then, even had he stayed here.

Would it be ok to export the earth using the armour.? Or would it be better to get three core and use the third core as earth.?

Ask your electrician. It doesn't matter what anybody here says - it's his name on the EIC - he is the only one who can decide about the armour.

 

[ban-all-sheds]

XLPE 2 core SWA in 16mm will hold 110A clipped direct, 99A or so buried in the ground.

Not much use if he's terminating it in accessories rated at, or joining it to cables rated at, only 70°..........