20amp fusebox...

[CHJ]

Tom, I have been living with the 1200 now since May (2005) as an extractor at and around my lathe and have no regrets as to performance.
I would not go so far as to say that it moves enough air to stop all the dust and small particles from distributing themselves around the shop (an impossible task with any lathe setup) but it is certainly up to my expectations. When loosely coupled to my thicknesser for a short test it coped with it's output.
I do now have the Collection Hose routed via a shavings trap (Plastic Bin on floor) so that the bag now only collects dust as I find changing the bag a bit of a bind.

 

[RogerS]

I blew the dust off my copy of the regs and there are eight stages in sizing a cable. Having said that I'd be very surprised if your average sparky did all the calculations but will probably rely on 'experience'.

For those who are dying to know what the eight stages are...then read on

1 - determine the current that you're equipment is going to draw (lots of interesting things like 'diversity' to consider here)

2 - select the current rating that will blow your fuse/trip your breaker...choice of fuse or circuit breaker is important and may have to be changed if cable sizes or loop impedance are too high

3 - apply appropriate correction factors (eg are cables run together/under loft insulation/fusing factor etc)

4 - divide 1 by 3 as appropriate to give you a 'tabulated cable current capacity'

5 - look up the tables to give you a cable size to suit 4

6 - check the voltage drop (thin cable + high current = volts drop at your machinery = they don;t operate efficiently and in extremis nasties will happen ..like your NVR switch may not hold on :twisted: ). The regs advise no more than 9.2v for 240v supply

7 - check that (under fault conditions) you'll not get a shock (because the earth wire in your cable is too thin basically)

8 - check that the cable won;t burn out under a fault condition when all that current is flowing down it and the fuse/circuit breaker is thinking about blowing/tripping

Alternatively you could run a 10mm cable

 

[devonwoody]

Funny things about cables, they seem to have similar problems to
cash; Inflation.

20 years ago I put in a 1mm cable for lighting, then 2.5mm cable was added for freezer, woodwork started up in garage so it went to 6mm, next stop appears to be 10mm, which I am reliably informed carries 63amps but down to 45A if loft insulation touches cable.

I reckon it wont be long before my cables are heavier than the incomming power supply company wire.

 

[RogerS]

But don't ignore the fact that you're not going to have everything on a the same time...so 6mm may well suffice