Ring circuit in garage with high amp compressor

[JamesHughes]

Hello all,

sorry to bombard forum with questions - got some unexpected free time, so doing all the jobs that have been waiting in the wings.

I am going to put a ring circuit round my garage. I'm using metal clad sockets, and PVC conduit. All well and good. But can I connect a compressor directly to the ring circuit - the motor rating is 13.7A, so would need to be wired in rather than via a 13A plug. At my old house I had it running off its own circuit via a small CU in the shed it was in.

Also, with regard to lights, I have three batten fittings I will be putting in. What is the best way to wire these in to the single light switch, keeping wiring to a minimum? A long time ago in a garage far far away I effectively had the usual lighting wiring to the first batten, then the other two run off as parallel 'spurs' from the first light so they all switch at the same time, but I am not sure that was the correct way to do it.

James

 

[JohnD]

a ring circuit must not have loads fused above 13A.

You might find you can run it off a 13A FCU.

If not, it needs its own radial circuit, fused at 16A, 20A or something.
Try it on a plug and see if the plug fuse blows.

 

[JamesHughes]

I have actually been using it off a plug recently, and no fuses have blown, so I may be OK. I think it may be Clarke overegging the pudding on power requirements. Its a big 'ole thing though...

So I guess I could either wire it in via a 13A FCU, or even just put in a socket and run it off that?

James

 

[sm1thson]

I think it may be Clarke overegging the pudding on power requirements.

13 amp fuses dont blow at 13 amp (or 13.1), basically 13amp is the most they can sustain, after that time comes into it but I seam to remember reading they could take 20 amp for 30 mins or something equally as unexpected which puts it into prospective. if it was me I'd use a 13amp fused plug without much worry, but whilst you are putting wiring in why not just give it its own radial.

 

[streetlighter]

Id wire it on its own radial circuit from a 16A MCB and connect it via a DP switch and 16A commando plug and socket.

 

[SeanT]

I seam to remember reading they could take 20 amp for 30 mins or something equally as unexpected which puts it into prospective.

The fuse can, it'll melt the plug though and blow the trip if there is one, seen it done when my old boss couldn't do the maths bless him...

 

[333rocky333]

For the lights go from first to second, then second to third,

this avoids having three wires in the first fitting,

Inside the fittings avoid having the wires going across the choke unit as this gets hot.

 

[JamesHughes]

Thanks for all the advice people.

I will try to wire in another radial I think, although even the first is going to be a Pita I think.

Is is permissable/advisable to do the following?

Because of the roof joist (flat roof) arrangement to get front to back I have to either drill through aload of joists for a bare cable, or run a conduit slung underneath the joists (which I think makes it vulnerable). Its more difficult running the conduit along the wall itself because of the occasional brick work piles jutting in to the garage. I will of course be using conduit for any low level work, and getting radial from socket level back up high, but can I just have bare T&E once up in the joists?

Same applies to the lighting circuit - much easier to drill through joists for wiring that to try and run conduit around slung under the joists.

Do people have any advice in this area?

James