Originally Posted by viator36
I plugged a neutral ground plug into one of my Yamaha EF2200 generator's 15A sockets and plugged a 15A cable into the other 15A socket and then connected the cable to my trailer. My EMS showed error code E 0 and 110v appliances worked fine. I hear rule of thumb is with 15A you are supposed to run one high wattage appliance at a time but with 30A you can do two at the same time. So leaving the neutral ground plug in I pulled out the 15A cable and plugged in my 30A cable to the generator socket and hooked up to the trailer. To my surprise the EMS showed error code E 1 for reverse polarity so the neutral ground plug worked for the generator's 15A circuit but flipped polarity for the 30A side.
But I still wanted to make the 30A side work so I bought another plug and this time made a live-ground plug instead of neutral-ground and plugged it into a 15A socket. My multimeter showed the other 15A socket had reverse polarity this time but the 30A socket had the correct polarity as I wanted! So I plugged the 30A cable to the trailer and sure enough the EMS showed code E 0.
I have a couple of questions. One, if my EMS is good with me using the L-G plug this way for 30A power is this the end of the story? I just keep the two plugs and use neutral ground one for 15A and live ground for 30A? Do you have any concern about it? Two, why the polarity of my generator is reversed between 15A and 30A like this? Does this happen to portable generators of other brands and why it works like this? Please no comment going in the direction of red vs blue camp feud here I just want to understand this electrical phenomenon.
Since the EF 2200, like most inverter generators does not do a neutral bond, the manufacturer does not have to connect the same side of the 15A connector to the matching side of the 30 amp connector. Many manufacturers reverse what would be the hot & neutral between connectors (since there is no hot or neutral) to save wire or make it easier to parallel the connectors.
If it was my generator, I'd switch the connections between the receptacles rather than carrying two bonding plugs.