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Arc Flash Labeling for single phase 240 volt panels

Question asked by roger.witt.cpn6 on Dec 19, 2016
Latest reply on Jan 5, 2017 by david.austin

What is industry standard to label Service Entrance panelboards and branch circuit panel boards in a commercial application rated at 240 volt, single phase, fed from 100KVA utility transformer?

IEEE 5.1 indicates the empirically derived formulas are for 3 phase systems only

               indicates theoretical formula (Ralph Lee) that single phase circuits can be used in this formula, but LEE's                formula is for above 15000v and for open air circuits not for circuits enclosed in a box.

IEEE 1.2 specifically states the formulas are not for single phase circuits


NFPA 70-116.16 seems to state that all panels are to be labeled to warn against potential electrical Arc Flash hazard

NFPA 70E 130.5  seems to require an arc flash assessment be performed however the formulas in Appendix D                                      and  IEEE 1584 are for 3 phase circuits only

NFPA 130.5(D)  provides the information required on an arc flash label


If the Tables are used  assuming the fault current and clear time will match the requirements,

is that the value to be used, the PPE Category, and if so since the PPE Category is 1, is the minimum arc rating for the PPE to be shown on the label to be 4 calories/cm sq?

Between IEEE 1584, and NFPA 70E and Appendix D, and if it is accepted a single phase circuit will not sustain an arc to reach 5 joules, it is difficult to understand what OSHA will enforce.


Just curious as to how this issue is being handled in the industry by others.