Ductape wrote:
OK, I will bite.
IF the ground was open, as reported- then how was the allegedly reversed "polarity" determined?
Think about it.
Good catch! If this was about a 3-light tester, the answer would be an easy it's impossible for the tester to determine both conditions. Since 2 of the 3 lights are wired to the ground terminal, only 1 light could possibly light with both conditions present, and it takes 2 to indicate reverse polarity. Note however that the original post said "bad ground", which a 3-light tester could possibly show if there was some voltage on the ground wire. Similarly, I'd think the EMS could possibly detect a "poor" ground with reversed polarity but the algorithm would not be 100% accurate. No matter anyway, the PI EMS book I looked at says the only ground fault it detects is "open ground", which of course can't be detected simultaneously with polarity detection, since ground is the reference for the polarity detection. If I were placing odds what's behind this, they'd be on a software bug in the EMS.
