Electric shocks off of machine mart arc welder

[jn100]

Hi im a newbe and this is my first post, and im a novice to welding; yesterday i had a go on my uncles Clarke weld AT100 arc welder bought from machine mart about 11 months ago. So, i set it up as in the instructions and it was doing as it should. So after 20 minites i decide to pack up, switch off the machine ect; so i take the standard 3 prong 240v plug out the wall (my hands were touching the plug prongs (the plug was removed from the socket) and im getting a tangy shock sensation (nothing heavy but noticeable), touched it again and the same sensation, then once again and it was ok.

So what i want to ask is what may have caused this as im paranoid now about using it again. Could this be caused by a bad earth clip on the welding leads ?, build up off static ? Is this normal ? do i have to earth the machine?

Hope someone out there can put my mind at rest, another question is this; can shocks off a small welder like mine be fatal? as it is DC which is more dangerous right?

And while im here one more question, whats the best rod to use for a stainless steel (motorcycle) motad exhaust ????

Thanks for any response in advance its much appreciated ?

 

[the snooper]

probably due to capacitors in it they hold some charge for a while.
now you know dont touch the plug contacts.

there isnt a lot of voltage at the electrode end so no it wont kill you

 

[Robotstar5]

And while im here one more question, whats the best rod to use for a stainless steel (motorcycle) motad exhaust ????

You will struggle to arc weld something that thin, mig welding is a better option

...and welcome to the forum

 

[pedrobedro]

I recently found out our washing machine does this if you touch the plug contacts after it's unplugged, another reason to keep well away from it.

 

[Dogbreath23]

Make an appointment to see an osteopath. It sounds like you might have a trapped nerve in your arm...

 

[jonnyBMX]

deffinitely could be due to the capacitors, they do hold a charge and by shorting the two contacts you could be discharging the capacitors using your hand! altough capacitors dont allow DC through them (machine is powered AC) and any capacitors used in DC are just DC blocks, could still be these causing the problem espicially as you say after a while it goes (maybe after they are fully discharged. just dont touch the plug contacts and you will be fine ahha!

 

[tiger99]

There are two ways in which this can happen. Firstly, if the welder is an inverter type, the energy storage capacitors may leak back into the mains input due to leaky rectifier diodes. That is more than enough energy to kill instantly, but if it is leaking slowly, as is likely, will not do much harm. You will feel 2mA approximately, 20mA may kill.

Secondly, on any welder or other mains-powered item, there may be interference suppression capacitors directly across the mains input. However, these should be shunted by a high value resistor to ensure that they discharge fairly quickly (well under 1 second normally). I suspect that your problem is with the latter, probably because the discharge resistor has failed (fairly unlikely) or not been fitted (very likely). The stored energy is likely to be non-lethal, but possibly very unpleasant.

Your welder should be CE marked, and that requires that it complies with, amongst other things, the EMC Directive, which will have required interference suppression capacitors, and the Low Voltage Directive ("low" means up to 1000V, not low in terms of safety). I suspect that it is not actually LVD compliant, and any CE mark is probably the well-known "China Export" mark, nothing to do with EU approval, in which case the supplier or imported can be in very serious legal trouble.

You should return it to the supplier, explaining what is wrong, and ask for a refund. If you do not get anywhere, Trading Standards are the people who deal with equipment which is CE marked but not in compliance with the regulations, and threatening to take it up with them should bring instant results.

Ideally the entire batch of similar welders should be condemned.

By the way, "Safety Extra Low Voltage" as it is known extends only to 32V AC or somewhat higher for DC, and the welding voltage on anything but a MIG or spot welder is potentially lethal, in certain circumstances. People have even been killed, very rarely, below the SELV limits. It should always be treated with respect. No need for panic, just sensible precautions, such as wearing gloves, so you don't change electrodes with bare hands when the welder is switched on, not welding while sitting or kneeling in pools of water, etc. All commonsense stuff.

 

[Wozzaaah]

^ Way to go Mr Scaremonger!
It's a Clarke, do you not think they'd have designed and tested their machines to comply with all EU safety regulations?
We're not talking some far east country with spurious QC, we're talking one of the EU's biggest suppliers of tools and equipment.
I'm not saying it isn't faulty, it may well be but mountains and molehills spring to mind when reading your post.

OP, you bought it from a reputable retailer so if you're concerned, take it back.