Machine-build EGC

[IAMAMT]

I have a machine build production line that has required 2/0 Equipment Grounding Conductor at 1000 amps as per NFPA 79. It has 10 arc welders on the machine. It currently has a 2/0 Welding Cable 20' long and must be able to move with the vibration of the machine. The OSHA Inspector will not allow the welding cable because of the potential of insulation damage and physical contact by employees. Any suggestions on what to use.

 

[charlie b]

I think you meant NFPA 70, better known as the NEC. Article 250.118(1) specifically states that a bare wire is allowed to be used as an equipment grounding conductor. There is no danger of a person coming into contact with such a wire, since it is intended to also be connected to the exterior, non-current-carrying metal parts of every piece of electrical equipment in the building.

 

[hotwire1955]

ask the OSHA inspector what he suggest you use and let us know.

 

[IAMAMT]

I think you meant NFPA 70, better known as the NEC. Article 250.118(1) specifically states that a bare wire is allowed to be used as an equipment grounding conductor. There is no danger of a person coming into contact with such a wire, since it is intended to also be connected to the exterior, non-current-carrying metal parts of every piece of electrical equipment in the building.

NFPA 79 is the Electrical Standard for Industrial Machinery. It is the transition from this standard to NFPA 70 that is causing the problem. NFPA 79 other requirements are used except EGC be protected from physical damage and terminate according to NFPA 70. It is a movable production platform with robotic welders on it. I hope this helps.

 

[Chev]

Can you run the wire through floor tray, rigid metallic conduit (clamped down), or unistrut (bolted to floor)? That would protect it. I build weld tool fixtures/lines for GM which also incorporate robots for welding, and that's what we do. We also use fencing/guarding to keep people away from hazards and our bonding conductors. Usually the wire can be routed/fastened in a manner that keeps it away from foot traffic.

To Charles E. Beck, NFPA 79 is the proper publication for machine tool applications, it is used in conjunction with NFPA 70 and NFPA 70E along with 29 CFR 1910 (OSHA Regs.).