Are 120VAC panels required arc flash label or just shock hazard labeling.? The IEEE-1584 equations does not go beyond 208VAC. We were told that these panels has to be labeled since there is potential of phase to ground fault. In this case, can a plant use both the IEA method for 480-208VAC and the tables for 120VAC single phase panels.? I always though that phase to ground in a a120VAC system would be a ground fault but have seen in some instances where an "arc" or "Spark" would occur but not sustained. I think using both methods in a plant may confuse people. Any suggestions would be appreciated.
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The IEEE 1584 WG is only now looking at the impact of single phase. It is a new project and the research budget is very limited which influences the timeline. A system is only considered a single phase circuit if the ENTIRE panel only has a single phase (out of three) into the panel and the associated neutral and ground wires. On the other hand, if you only have all single phase breakers, but the panel bus is three phase, that system will be considered three phase and should be labeled for both shock and arc flash. Single phase does not have to be labeled with arc flash at this stage (no standard in place), but the SHOCK hazard MUST be indicated.
Zarheer , in your last comment you said "if you only have all single phase breakers, but the panel bus is three phase, that system will be considered three phase and should be labeled for both shock and arc flash'" does this still apply to equipment that has been determined to be less than 1.2 cm2?
Less than 1.2 still has a shock hazard and the less than 1.2 is calculated at 18 inches away. So there could be more than 1.2 for the hands.
The NEC and NFPA 70E would allow a generic label for shock and arc flash with a PPE level but that PPE might be ONLY gloves rubber insulating IF it is shock only and AR gloves if no shock is a risk in the operation etc but the hands need arc flash protection. This certainly depends on the equipment and the task. You may require nothing but this has to be part of the risk assessment. Shock hazard is likely always present in some condition on electrical equipment.