I have a question regarding arcing gap discontinuity in CSA Z462 D.8 derived from CSA Z462 tables D.6 and D.7. For visualization purposes, check a plot displaying arc gap as a function of system voltage - all according to tables D.6 and D.7 from CSA Z462, or tables 410-1 and 410-2 from the NESC standard.

The jump at 46kV point is most

**obvious **and

**alarming**. The problem with the 10kV/in number and arc gap calculated based on it is that it is used in calculation the distance from the arc to the worker, namely CSA Z462 Table D.7 Note 2 states

*the distance from the arc to the worker is calculated using the minimum approach distance from Table 441-2 of IEEE C2 and subtracting two times the assumed arc gap*.

Any comments?

Sincerely, M. Furtak, C.E.T.

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