Why is my belt sander electricuting me?

[Ives]

My belt and disc sander is only about a month old and today and the last time I used it, it gives me shocks when I touch the metal tables on it. What is this?? I don't notice it on the bandsaw or scroll saw, but I don't want to go trying it out. If they all shocked me I would think it might be the second hand extension lead I got off Freecycle, but I only notice it on the belt sander.

 

[adidat]

might be static or the tool is not earth properly, send it straight back!

adidat

 

[CHJ]

Get that Free Cycle extension lead checked out by someone qualified to make sure that it is wired correctly (PAT Tested), likewise the belt/disc sander needs PAT checking for safety compliance.

Safety earth failure in either may be the problem leading to starter capacitor or suppressor feed to the sander casing causing your shock but it could also be far more serious with a live wire shorting to an ungrounded component.

Static generated by the belt may also be the cause but should not happen if the sander and supply cable are correctly grounded.

I must say that for anyone not conversant with electrical safety to use electrical components picked up on freecycle or car boot sales is an accident waiting to happen.

 

[studders]

I must say that for anyone not conversant with electrical safety to use electrical components picked up on freecycle or car boot sales is an accident waiting to happen.

I'll second that, especially when you get some twit who uses an Earth core for a Live connection because they couldn't be rsed to get the proper cable, as I recently found. :roll:

 

[Ives]

I just used the sander again with a different lead and it's fine! I already emailed Axminster telling them their sander was electricuting me! Oops.

Can you get old extension leads fixed for cheap or should I just buy a new one?

 

[RogerBoyle]

I just used the sander again with a different lead and it's fine! I already emailed Axminster telling them their sander was electricuting me! Oops.

Can you get old extension leads fixed for cheap or should I just buy a new one?

Unless you know the history of it and/or are capable of competently checking one out
Just buy a new one

Roger

 

[Digit]

Ok, so a correctly connected earth lead may be preventing shocks, but that is doing nothing for the problem. There should be no current for the earth conductor to bleed away, unless it is static of course.
I would have the sander checked.

Roy.

 

[Paul Hannaby]

There should be no current for the earth conductor to bleed away, unless it is static of course.
I would have the sander checked.

Roy.

Not necessarily - there is often a small amount of leakage to earth if there are devices such as filters fitted to reduce electrical interference from motors or power supplies etc.

 

[Benchwayze]

I just used the sander again with a different lead and it's fine! I already emailed Axminster telling them their sander was electricuting me! Oops.

Can you get old extension leads fixed for cheap or should I just buy a new one?

Buy a new one Ives.

I wouldn't even consider buying a used extension lead and apart from replacing a fuse, I wouldn't have a faulty one repaired.

They are cheap as chips brand new. For twice the price of chips you can get a good quality job, with anti-surge, and separate switches on each outlet. Don't take risks with your life my friend, please?

And I am wondering why your faulty sander didn't trip your supply, via the consumer unit. If I have a faulty appliance, and I switch it on, the electrics immediately switch off.

HTH

 

[Hudson Carpentry]

I had this but with something in the house years back. I needed an extension lead and used an old one we had laying about but everytime I touched the item (forget what it was) a small shock occurred. The item was fine but the extension had a small earth leak. Threw the lead away and grabbed another (we have 100's of the things).

 

[Digit]

Granted Paul, but he would have to be sensitive to feel it, and if that is not the case he has a problem.
I checked a machine once that the operator claimed was giving a shock, he was right, less than 12volts. That is the lowest voltage I personally have come across that a person could feel. I couldn't BTW.
Also, if he is wearing normal foot wear, even with a concrete floor that leakage needs checking. I would also point out that wood dust can produce an ideal path for leakage.

Roy.

 

[Hudson Carpentry]

Granted Paul, but he would have to be sensitive to feel it, and if that is not the case he has a problem.
I checked a machine once that the operator claimed was giving a shock, he was right, less than 12volts. That is the lowest voltage I personally have come across that a person could feel. I couldn't BTW.
Also, if he is wearing normal foot wear, even with a concrete floor that leakage needs checking. I would also point out that wood dust can produce an ideal path for leakage.

Roy.

5v is the smallest (knowingly) I have ever got a shock from.
In fact I got a shock from an HDMI lead today.

 

[Digit]

Unless the regs have changed since I retired HC the min figure for insulation between conductors and earth is/was 1 Meg ohm. At 220 volts this produces a leakage current below that which will trip an RCD, so unless there is no RCD the combined voltage and current is unlikely to be felt, unless the victim is in bare feet on damp ground I would suggest.
I grant you that some people are more sensitive than others, but to me, a machine that is producing a leakage that can be felt should be tested. It is not likely to improve, unless it is damp of course, when drying out could rectify the problem.
Plus if the OP has no RCD installed I would suggest that he has one installed, pronto!

Roy.

 

[Hudson Carpentry]

Unless the regs have changed since I retired HC the min figure for insulation between conductors and earth is/was 1 Meg ohm. At 220 volts this produces a leakage current below that which will trip an RCD, so unless there is no RCD the combined voltage and current is unlikely to be felt, unless the victim is in bare feet on damp ground I would suggest.
I grant you that some people are more sensitive than others, but to me, a machine that is producing a leakage that can be felt should be tested. It is not likely to improve, unless it is damp of course, when drying out could rectify the problem.
Plus if the OP has no RCD installed I would suggest that he has one installed, pronto!
Roy.

Digit I never objected or questioned your advise and agree that the OP should have the machine tested and should be running his tooling from an RCD protected circuit. I was merely making small talk on my experience on shocks and from lower voltages.

However its very possible that the extension lead had a leak and as the earth on the case of the machine would technically be connected directly to the earth in the extension lead it was directly transferred to the user that way. The leak could be caused by some sort of semi conductor that altered the voltage or current. The semi conductor thought of in its meaning of term rather than its lateral electronic component description, would bring me to conclude that a build of dust (or alien material) inside the extension lead could do just as the OP (and I) have experienced. Dust has far to much resistance as a conductor to hold any sort of noticeable current plus the drop it would experience when the electrons hit the much lower resistance of copper earth cable could slow the current down more to a point where once the circuit via human has continuity the diverted electron flow is to little for the RCD to worry about or even notice. In the correct conditions: high humidity, sweaty hands etc, a small arc could occur giving the user a sense of being shocked.

Anyhow this would be an AC shock which feels different to a DC shock which feels more like a static shock and to someone thats never been subjected to an AC shock will not know the difference which is why the OP should have the unit checked even if the logic points to the lead.

EDIT: After reading the OP again he states he never tried anything else via the lead so really not only does the tool need testing, so does the lead and my comment of the logic pointing to the lead is invalid.

 

[Digit]

EDIT: After reading the OP again he states he never tried anything else via the lead so really not only does the tool need testing, so does the lead and my comment of the logic pointing to the lead is invalid.

In my experience HC the majority of leads become faulty eventually, especially those without a moulded on plug. Extension leads in worshops are a menace IMO. People will spend thousands on machines then skimp on the electrics, not good.

Roy.

 

[Benchwayze]

EDIT: After reading the OP again he states he never tried anything else via the lead so really not only does the tool need testing, so does the lead and my comment of the logic pointing to the lead is invalid.

In my experience HC the majority of leads become faulty eventually, especially those without a moulded on plug. Extension leads in worshops are a menace IMO. People will spend thousands on machines then skimp on the electrics, not good.

Roy.

That's why I made a picnic table at materials cost, for a qualified electrician I know! :wink:

 

[Digit]

My wife calls me Spock 'cos I'm very 'logical' John, and one of the things that puzzles me is the oft repeated statement, here and elsewhere, that 'electrics are dangerous!'. Then they disappear into the workshop with TS, BS, router etc.
I'll hazard a gues that the A & E sees more workshop accidents than cases of electrocution.

Roy.

 

[Benchwayze]

My wife calls me Spock 'cos I'm very 'logical' John, and one of the things that puzzles me is the oft repeated statement, here and elsewhere, that 'electrics are dangerous!'. Then they disappear into the workshop with TS, BS, router etc.
I'll hazard a gues that the A & E sees more workshop accidents than cases of electrocution.

Roy.

I s'pose electricity is only dangerous if you don't understand it; and even then it isn't the 'juice' itself, but the persons handling the equipment! Same goes for anything really. Guns, cars, and so on. (I don't understand electrics myself; at least not well enough to mess with installations and suchlike. So I have my pal install outlets for me.) (hammer)

 

[Digit]

Understood John, but we none of us knew anything about woodwork at one time. I was luckier than most in that I served an apprenticeship in wood, and other materials, in the aircraft industry. Electrics follow fixed rules, I wish wood did! :lol:

Roy.

 

[Benchwayze]

Understood John, but we none of us knew anything about woodwork at one time. I was luckier than most in that I served an apprenticeship in wood, and other materials, in the aircraft industry. Electrics follow fixed rules, I wish wood did! :lol:

Roy.

Yes Roy, I accept the point re woodwork, but then it isn't against the law to make and install your own cabinets and furniture; not yet at least.

Whilst I am sure I could learn how to rewire my home, I would have to suffer an inspection by a qualified person. So that being so, let that person do it! Incidentally, I agree with that law/regulation, especially in semi-detached or terraced dwellings!