3 phase cable question

If it's enclosed in conduit, trunking a wall etc. 6mm^2. If it's open, clipped to the outside of the wall or on a tray, 4mm^2.

That's based on the worst case 70°C PVC.

Have got reasonable spec on their cables.

An isolator or Commando plug & socket on the wall should be enough.

Regards

Thanks Mark It will be SWA clipped on the wall.

Don't recall seeing a neutral in the consumer unit, but there is a neutral coming from the machine, don't know why. I'll get cable with it in just in case unless advised other.

Also, the machine has some sort of very large transformer box on the floor, vendor said it was something to do with power spikes. I think its something to match the voltage I have to the machine, no capacitors, so guess its not something to smooth the power. By now its obvious I'm not an electrician !!

Regards Bob

Can I ask for a recommendation for a usage meter between consumer unit and machine please.I will us TLC, they are around the corner to me. bob

I dunno how it is in the UK as far as wiring machines go, but here in the US the neutral would be for a low voltage single phase load. For example, the machine might run off of 230 VAC but have a single phase,

120 volt work light. Code in the US says the work light can be powered from the neutral and one of the legs supplying 230 VAC three phase. It could also be run from a transformer but that would be more expensive. My power is supplied at a voltage that is right at the highest allowed by code and I do get times where the voltage goes even higher for short periods. I cannot get the power company the lower the voltage unless I want to pay for a new transformer on the pole and the installation. I only have one machine which cannot tolerate this higher voltage, all my other machines can tolerate it by just changing transformer taps in the machine control cabinet. So for the machine which has a problem with the higher voltage I have it connected to a pair of "Buck-Boost" transformers wired in buck configuration to lower the voltage about 20 volts. I wonder if that's what your transformer is. If you google buck-boost you can see what I'm talking about. Eric

Buy a recon 3 phase electricity meter from ebay.

Bob,

Not wishing to put a spanner in the works, you said the machine plate states

32 amps, is that Max load or across each phase, I've had many a customer miss read our drawings and under rate the supply.

Mart>>> On Sun, 7 Apr 2013 19:01:41 +0100, "Emimec"

I'll second the recon meter from EBay. I've got a GEC Meters (St Leonard's Wks, Stafford), EBay meter to check how much the shed's costing me. It's identical to the one that the electrikery board uses for my excessive electric bills.

Update, plus another couple of questions. Firstly I should explain this project is for the lad in the workshop next door to me. The machine plate only says 32A, so hopefully that's full load, and apparently the previous owner had it on a 32A supply.

He has got the 4mm cable now, and also a meter from eBay, very similar to this Item number:

350507419360 But a 3 phase version.

Question now is, its obvious that meter tails fit into this, but his tails will come from a MEM type fused distribution board which has the knockouts for the usual SWA gland fittings. But what would be used if running meter tails to this ? Same problem arises with the tails from the meter, somehow they need to join up with SWA from the machine ? Also, what powers the meter, is it the 3 phase itself ? As I doubt there is a neutral in the distribution box. Bob

You should be able to fit normal glands from the panel and maybe put the meter in a box to terminate the outgoing SWA Most meters (all?) will be happy without a neutral. The incoming power is used to power the meter. There are quite low Power specs that the meter has to meet are quite low (2va per phase from memory) so the running cost is neglible but not registered by the meter. If the power drawn is below a certain level, the meter does not register at all. - called 'anti creep' which is a hangover from dial meters and has found its way into the specs for electronic meters. If you are using no power and neither is he, then the anti creep in your meter will not register the power used to run his meter.

hth

Bob

Many thanks Did exactly as suggested, got a box big enough to house the meter. Thanks bob