Plugging shore power into inverter

RDMueller wrote:
One other consideration (I just recently found this out myself). If you have a built in electrical management system like the Progressive EMS-HW30C or EMS-HW50C (and might apply to other brands as well) - do NOT plug your shore power cord into an inverter. There is some discussion about whether a PSW inverter is ok, but the manufacturer says commercial power only. So, if you have one, you will probably want to bypass it before plugging into an inverter.

Progressive Industries does say in the EMS-HW30C / EMS-HW50C owner's manual to "never" plug their EMS units into an inverter. However, that warning is offered out of an abundance of caution because there are "inverters" and there are "inverters", meaning with some designs there's no reason it can't be used to feed an EMS while others could spell a death knell for the EMS. The Progressive EMS is particularly vulnerable to any non-sine wave signal so one wouldn't want to use it in conjunction with any inverter that isn't guaranteed to be true (or "pure") sine wave. One also certainly wouldn't want to plug an EMS into any inverter with a 60/60 centre bonded neutral output but that's easy to determine beforehand - just put a meter between ground & neutral and if you see 60 volts it's a centre bonded neutral output. This design would also prevent using a G-N bond which the EMS would most certainly require in order to not detect what it thinks is an open ground situation and therefore not pass the signal. That said, there are a couple of very good reasons one might want to have their EMS in the system even when the source power is an inverter - 1) it's simply easier to not have to bother removing it each time you switch to inverter power, and 2) the EMS display is really handy for monitoring various parameters of the incoming source power, just as it is when using shore power. Can it safely be done regardless of the PI caution? - yes, one certainly can, as that's exactly how I'm running my own EMS-HW30C with a 1000 watt true sine wave inverter as source power. :B