Talk:Arc flash

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I made some changes to make shorter/cleaner and remove some of the concrete statements that are not always true. ~Bajarider

Took out the paragraph that states breakers don't reduce the hazard - Thousands of calcs on 100's of different devices - They make a difference and so does almost any fuse. Fuses are generally quicker on higher fault currents and breakers are generally quicker on lower faults. ~Bajarider

Changed the note that said 480v is not usually a hazard to 240v according to the appendix in 70E and the IEEE1584 notes. ~Bajarider

I don't like the last paragraph;What OC is going to let 20KA through for 10 cycles? Very unusual. ~Bajarider

Could happen - 20 kA could easily be the current let-through by a 1000 kVA 5% 480 V 3 phase transformer, and though we'd like to believe breakers always open in 5 cycles, 10 cycles is not inconceivable. Sometimes it's the backup breaker that clears the fault. --Wtshymanski (talk) 13:54, 17 April 2008 (UTC)

[edit] Voltage

There is a problem with this: "...systems operating at less than 240 volts phase to phase (120V to ground) when fed by...".
Either the phase to phase voltage is 240V and the phase to ground is 138V, or the phase to ground is 120V and phase to phase is 208V.
V_{line-line} = \sqrt{3}\cdot V_{line-neutral}

Consider a three wire single phase circuit, 120/240 V. True, I don't like calling the energized conductors of a single-phase circuit "phases", but not everyone is as fussy as I. --Wtshymanski (talk) 13:54, 17 April 2008 (UTC)