I came across this post because this weekend when I swapped my shore power cord from the 120vac 20A I used at home to keep chargers in service to my 240vac 50A cord so that I could turn on the air conditioner while working in there I noticed that my Powerline Energy Monitoring System was also showing that only 30A service was available. I checked incoming voltages all along the way and had 120v on both Line 1 and Line 2 (and 240 across both Lines) so I was quite puzzled. Thankfully I found that I wasn't the only person who had scratched my head over this.
I found a link to the Powerline EMS Manual online. While reviewing the manual it realized that in order for the system recognize the presence of 240vac, it must see that there is 120vac on Line 1 and 120vac on Line 2. It does this by monitoring two circuit breakers - one serviced by Line 1 and one serviced by Line 2. Then I remembered that I had shut off a few circuit breakers.
Low and behold, I had shut off one of those two breakers that is monitored by the EMS. When I flipped it back on my Powerline EMS Display showed that 50A service was available.
So, if you're having this issue, the first thing to check is to make sure you haven't shut off a circuit breaker and made the EMS "think" only 30A service is available?
