h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I have a shed in the garden with an electronically speed-controlled wood lathe, which sometimes knocks out the RCD in the main distribution box in the house.

The shed is supplied from its own VB16 fuse-switch via about 10 - 12 M of 2.5sq mm oval cable to the garage...
From the garage, 20ish M of 2.5sq mm armoured cable to a mini distribution box in the shed.
Within the shed (supplied from the B16 fuse-switch) is a ring main with quite a few double wall-sockets.

I laid the cables and the ring main, then called in a professional to check it over and connect up.

When the lathe causes the problem, the spike(?) bypasses the whole shed circuit and the main fuse-switch, knocking off the RCD.
It happens with the lathe alone or when the dust collector is already running.

I'm reasonably sure, but not certain, that it happens when it's cold - probably not above 8 or 9 degC. It happens when I switch on at the wall though I think it has happened a couple of times when switching on the control box - can't be sure.

I'd be most grateful for any help - I imagine I'll need to buy a gizmo to stop interference getting _out_ of the equipment.

What should I get? Where from (RSC/Maplin)? will it be self contained - or need knowledge?

Thanks in advance...

That was meant to be the title!

Get an amp meter and check each appliance running seperately then add up the total of amps drawn by your workshop.
If the amps exeed the amps controlled by the fuses in your present single phase 250 volts fuse board you may have to have your work shop rewired to a three phase power board.

Don't fool around with your wiring if you are not an electcian because it would seem you are at risk already.

Before you try anything else, first get a qualified electrician to check your power supply because you don't get two chances if there is a fault.

Another thing is to make sure your work area is bone dry under foot and not open to outside damp, also a heavy rubber mat to stand on when operating your lathe. All the best. T

Get an amp meter and check each appliance running seperately then add up the total of amps drawn by your workshop.
If the amps exeed the amps controlled by the fuses in your present single phase 250 volts fuse board you may have to have your work shop rewired to a three phase power board.

Don't fool around with your wiring if you are not an electriccian because it would seem you are at risk already.

Before you try anything else, first get a qualified electrician to check your power supply because you don't get two chances if there is a fault.

Another thing is to make sure your work area is bone dry under foot and not open to outside damp, also a heavy rubber mat to stand on when operating your lathe. All the best. T

Get an amp meter and check each appliance running seperately then add up the total of amps drawn by your workshop.
If the amps exceed the amps controlled by the fuses in your present single phase 250 volts fuse board you may have to have your work shop rewired to a three phase power board.

Don't fool around with your wiring if you are not an electrician because it would seem you are at risk already.

Before you try anything else, first get a qualified electrician to check your power supply because you don't get two chances if there is a fault.

Another thing is to make sure your work area is bone dry under foot and not open to outside damp, also a heavy rubber mat to stand on when operating your lathe. All the best. T

By the way I am going back to school to learn how to spell so please do not call on me. :0)T

One last thing me owd flower, some fuses are called "Lazy Fuses"
Because they open circuit when a lot of amps are drawn since the fuse wire gets hot and one end parts contact where it is anchored.
when the wire cools it makes contact again and all seems to be o.k.
until the next time it is used.
The quickest remedy here is to get a new fuse and fit it and see if you now have the same problem.
If it is an old type fuse you can renew the wire but with a modern fuse you cannot, since the wire is embedded in the pot body of the fuse. Slainte. T

RCD ?? is that what i would call a GFCI ??
Ground Fault Circuit Interruptor ?
Cuts off the power if it detects an imbalance between Line and Neutral currents greater than 10mA...ie: if the current starts going through YOU instead of back down the Neutral wire.

I have found that when an already GFCI protected appliance is plugged into a GFCI protected outlet, that they interfere with each other and cause the supply breaker to trip.

Check to see if anything you are connecting also has perhaps an inbuilt GFCI trip that is interfering with the protective circuit back at the house.

If so, you may need to disable the GFCI on the appliance.

alec.

Danke Alec, beschtimt!
Thanks Alec,correct!

Oh deary me. I must have thrown this one out before an answer appeared, and have just refound it.

Thanks folks.

I don't think it's a loading problem - Nominal load of the troublesome wood-lathe is less than the bandsaw which switches happily with my dust extractor - as does my Router (which is electronically speed controlled).

I'm no expert but do have some experience, but very little with 'backward' RFI - which I strongly suspect is my problem.

It's got me convinced that it *is* temperature dependant.

If anyone is still watching, what do I buy to prevent/reduce internally induced noise from getting back into the mains?

I'm considering breaking the 'local' ring main & trying that...?

Alec's post (8) :

Your GFCI sounds very like it. I've just read your post again and I'd be very reluctant to get into disabling anything of that nature too soon.

Lazy fuse (TtP, post 7) Hmm, I'll try that.

RtB