Wiring in a Workshop

[Stuartgb101]

Hi, looking for help in linking the start of a 2nd machine to the starting of a 1st machine.
All machines are single phase, 240v.
I want to link a table saw to a dust extraction unit, such that the extractor comes on/off when the saw turns on/off.
Would this work and be safe please ?
1. Connect a brown/live 4mm2 cable to the 'on' terminal for the table saw. This is the terminal feeding the saw motor.
2. Connect the other end of the 4mm2 live to the 'on' terminal on the dust extractor. This is the terminal feeding the extractor motor.

Many thanks.

 

[ericmark]

The way it was done where I worked there was a flap, so the extractor had to be running before the main machine could be switched on.

The main consideration is the start current, having them switch on together not really a good idea unless you have a very good supply, better with a staggered start.

 

[Stuartgb101]

Thanks for the reply.
The workshop has it's own supply with a dis board.
I have run 3nr 4mm2 radial supplies, each with a 16a breaker.
The saw and extractor are on different radials.
Occasionally the saw would 'blow' a 13a fuse, so II fitted a 16a fuse & now it's fine.
Does any of that help me ?

If not, then I'll fit a separate switch onto the saw and run that back to the extracter.
If I do that, will I need to run live, neutral & earth to the extracter, or just a live to it and splice into a nearby radial to pick up the neutral & earth ?
Thanks.

 

[Taylortwocities]

The workshop has it's own supply with a dis board.

A start up current will be an issue, can you describe how the feed arrives at workshop. Is it an MCB in the house CU (what value) or a switch fuse direct from the supply, again, what size fuse. Thank you.

 

[Stuartgb101]

Thanks for the reply.
I live in France, and the installation complies and passes current regulations.
I have 12kva coming into the house.
I have added a steel/armoured underground supply to the workshop (15 metres away).
Overkill !
The electrician who made the connections said the cable would power half the local hospital !
The house CU is modern, and the workshop supply from it has a 32A breaker.
The CU in the workshop is a 5yr old UK unit.
In the workshop, I have one circuit dedicated to general lighting and 3 radial power circuits (each with 16A breakers).
Ring mains and twin and earth are not permitted here, so I have run radial circuits (nr 1, 2 and 3) using individual live, neutral and earth cables (4mm2) in conduit.
Radial 1 will power the saw and extractor - nothing else.
Does this help ?
Thanks.

 

[Taylortwocities]

The house CU is modern, and the workshop supply from it has a 32A breaker.

If it is a B32 that may trip on start up if you already have a reasonable load running.
You may need to swop that for a C32,or even D32 - subject to EFLI measurements.

Essayer pour voir

 

[Stuartgb101]

Ok., many thanks.
Am I ok to run just a live from the table saw to the extractor (as mentioned earlier) ?
Thanks.

 

[blup]

You can daisy chain the two like adding a light on a circuit but as said the surge current should be checked. Different rules might apply In France

 

[SUNRAY]

Ok., many thanks.
Am I ok to run just a live from the table saw to the extractor (as mentioned earlier) ?
Thanks.

No no no.

Youhave 2 circuits with individual overcurrent protection devices, by the sound of it you will be trying to run both machines on the same device and introducing a borrowed neutral situation with all the potential shock risks during maintenance etc. Chances are the existing 16A device will not cope with that. Also starting the extractor will also start the saw - very dangerous!!
What control gear do you have in both machines?

 

[pete01]

If the extraction is a small load you could add another fuse and contactor switched by the saw switch and put the extraction through that, any emergency stops etc would stop both saw and extraction.

Then it would all be on the same feed.

 

[SUNRAY]

If the extraction is a small load you could add another fuse and contactor switched by the saw switch and put the extraction through that, any emergency stops etc would stop both saw and extraction.

Then it would all be on the same feed.

That's what I'm aiming at but trying to find out what is there first and also to establish if the extractor is used for anything else?