I am attending a school where the welding tables have been welded to the metal wall of the booth. The 220 ac service is attached to the booth, so the work lead grounds to the safety ground and makes the machine case which is grounded hot,[an arc can be struck on the case of the machine or the table it sits on], there is also no place in the booth which s not hot. I have been told by welding suppliers and a major manufacturer that this is hazerdous and illegal,they stated that half the ocv is coming through the work lead and an unknown Volt/amp load will also go through the saftey ground which is much smaller than the work lead risking a meltdown and fire. OSHA also has said it is not correct, but they have no jurisdiction, this being a state school. The dept head, an AWS-CWI says there is no problem with this setup. I have measured 50 Volts and 20 amps coming off the wall. Who is right, I feel this is enough to kill, and it makes working and learning a trying experience since no where can you lay a gtaw or smaw lead down without risking a short circuit.
Thanks for you input, Paul
You are correct with your observation, your instructor is incorrect with his. There is a difference between a ground connection (which is a electrical connection for the equipment itself) and a workpiece lead connection (which is commonly referred to as the ground connection - although this is nonstandard teminology) at the equipment (secondary) output. The local building codes have jurisdiction here wether or not it is a public building, they still have to comply with local jurisdiction requirements.
I would document the time and place and possibly have others present and make the instructor or school aware of the problem in a formal fashion, that way if someone does get hurt (hopefully not), the instructor or school cannot say they were not aware of any problems.
Take Care and use caution.
You may be attending a state school but everone has the right to work and learn in a safe environment.
If the equipment was not installed by a qualified and licenced (spelling could be wrong) electrician (and it sounds like this MAY be the case)
you need to document your concerns and find a way to drive it home.
Why not simply print this and give it to the qualified department head as something you came across.
It may not be up front but then again you need to protect yourself
Dirk
Why not talk to the local Fire Chief ? I bet he has some thing to say about it.
I think you will find the welding equipment manufacturer doesn't recommend the set-up you described either. That may be another avenue you can check.
Also, the insurance underwriters for the building will have some regulations to follow.
CHGuilford
I remember being told that if you don't have a RCCB, residual current circuit breaker, fitted, and the electrician knows you using the circuit for welding, it's illegal for him to fit the circuit (In the UK). And it means if you get fried you can take him to court. When I was asking around for a price on a breaker for my house they were mentioning hundreds (Burn-out fuses aren't good enough for welding anymore over here I don't think). So I asked if he could just fit the line and I would accidentally use it to weld on now and again. He went away and came back saying that the only way he could do that was if I was in a Faraday cage. Could their grounded room be an attempt to overcome paying for breakers? I was a little worried when the electrician claimed to be taking down 'details' from the welder, when what he was actually doing was looking for the wattage. 'Can't you just bolt things togther?' Was one of his alternatives. The whole house blacks out if we use the wrong plugs now he's been at work.
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