Static or what?

[Bob Abell 2Participant @bobabell2]

Got a bit of a tricky problem here, chaps

Have a Record bandsaw and Vax vacuum cleaner

Both are plugged in the wall sockets and both have sealed plugs

I`ve noticed on several occasions, when cleaning up, that sometimes my hand touches the bandsaw…….I get a tingling mild electric shock!

On repeated touches, there is no tingling…..But I don`t push my luck!

Is this static or what?

How can I be sure the equipment is safe?

Can I use my voltmeter somehow?

Sparkling Bob

[Bob Abell 2Participant @bobabell2]

[Dave MilbournParticipant @davemilbourn48782]

If the shock doesn't happen when touching for a second time then it's safe to assume it's static. Probable cause is the bristles on the bottom of the cleaner nozzle rubbing the carpet or floor. You need one of those anti-static straps that you sometimes see on cars; staple it to the turn-up in your trousers and all will be well…….

or pay a cleaner.

[Paul TParticipant @pault84577]

Bob

Serious matter

Yes it could be static but it could also blow your head off so don't try and solve it with your voltmeter.

The household wiring should be urgently tested by a qualified domestic electrician.

At the very least if you don't have RCD's fitted at your main fusebox you should fit RCDs to all of your workshop equipment.

Paul

[shipwrightParticipant @shipwright]

Bob,

Firstly and importantly you need to rule out possibility of mains supply faults. Is your band saw earthed properly ? Use multimeter to check continuity of earth lead and that the stand of the band saw is connected to earth (via the mains lead). If you have a Martindale mains tester you can easily check that your domestic mains socket is correctly wired up.

Assuming that all is well with the mains supply then the mild shocks that you receive could be due to static build up when you saw – the particles of dust that are a byproduct of sawing can become electrostatically charged. On another website there was some discussion of this effect – apparently the dust extraction system tubing is usually fitted with a wire to provide a "ground". As I don't possess a bandsaw I have no direct experience.

Ian

[Bob Abell 2Participant @bobabell2]

Thanks chaps

I think I will get it checked out by the Electricity board, for peace of mind

I think it is static from what you say, but it is best to be safe than sorry

Many thanks to all……Will keep you informed

Bob

[TelstarParticipant @telstar]

Bob

The shock is most certainly static. As you suck the sawdust up the plastic hose on the Vax it creates a dc voltage, this charges you to the same voltage, when you touch an earthed object (in this case the saw) you discharge to earth giving you a shock. The floor covering and the shoes you wear contribute to this. A hotel I was called to to check where guests were getting shocks from the light switches and lift buttons was traced to the 'new' carpet that had been laid. Walking over this 'Nylon' carpet was causing static to generate in the Guest then as they touched an earthed object and discharged they felt a shock. Normal voltmeters don't measure static voltages you would need a specialist "electrostatic voltmeter" to do this.

Ironically if the sockets were not earthed properly (which yours obviously are wired correctly) you probably would not get a shock In hospital treatment areas staff wear "clogs" that have conductive inserts in the sole of the clog and a small brass 'drawing pin' in the bottom to stop static build up as they walk over the floors in these areas, similar "Anti static" foot ware is used in the electronics industry.

This doesn't help with your shocks, but gives you some reasons as to why.

Tom

[Bob Abell 2Participant @bobabell2]

Hello Tom

Many thanks for your explanation

You are quite right, it was static

I called a Sparkie round and he checked the Earth connection of the Bandsaw, by inserting a meter cable in the wall socket earth conn and touching the Bandsaw with the other cable, the earth signal conn was there

It was obvious really, the the Vac is made of plastic, so I don't think there was any danger

But we can't be too careful!

Bob

[Dave MilbournParticipant @davemilbourn48782]

I'm pleased that Tom agrees with me; I still think you'd look kinda cute with an earthing strap stapled to your trousers, though. Maybe you could paint fiery teeth on it, too.
DM

[TelstarParticipant @telstar]

Hi Dave

The car type strap is a bit OTT . In the modern era you could use a wrist strap, **LINK** these are fitted with a current limiting resistor which allows the static to bleed to earth, with no shock.

Tom

[Dave MilbournParticipant @davemilbourn48782]

Tom
"A bit"? I'd hoped it was so totally OTT that Bob might take it seriously! I was eagerly anticipating a picture of his trousers, suitably earthed. As the much-lamented Robin Williams said, we're all born with a little bit of madness – don't lose it!
I have and use a wrist-strap and bench-top mat for antistatic work e.g. handling PIC chips, MOSFETs and the like. Haven't lost a chip or had a jolt in XYZ years. Mine's a bit more sophisticated than most would really need **LINK**

Dave M

[CookieOldParticipant @cookieold]

Hi Bob , I bought a Record Power BS250 bandsaw about 6 months ago and touch wood never had a issue , but i wondered why my wife keeps saying my hair is frizzy when i come in from the work shop HA HA .COOKIE

[Dave_PParticipant @dave_p]

Another tip is not to wear nylon knickers or stockings/tights.

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