On 7/12/13 5:51 AM, Bill Weinel wrote:
On Thursday, July 11, 2013 07:31:59 AM Jim Lux wrote:
The bonding wire needs to be big enough to carry the maximum expected
fault current without melting. The worst case for this is not
lightning, but a local medium voltage power line shorting to your
wiring, because it could source several hundred amps for seconds, before
something trips. Lightning has really high peak currents, but the pulse
only lasts 50 milliseconds, so there's not much energy dissipated in the
grounding conductor. (AWG 10 is big enough to handle all but the largest
lightning strokes without melting)
True. That's why I prefer larger conductors for the 'just in case' scenarios.
Thanks for the corrections and observations Jim.
And I find that I made a mistake too.. the lightning pulse is typically
about 50 micro seconds long, not 50 milliseconds. 1-2 microsecond rise
time from 10% to 90% and then a fall time 50 milliseconds to 50% is a
standard test waveform.
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