EMS units are recommended for use with commercial power only

there is no MSW generator, unless it was early model/prototype of inverter generator
and installed inverter with power pass thru, should be after the EMS
hard wired or portable

the only case it would not be, is when using the shore power plugged into the inverter, with a hard wired EMS

you just need to rethink your electrical setup

These are exactly the same concerns I've been dealing with as well and as discussed in this thread. Progressive unfortunately hasn't exactly been forthcoming with clear answers to my questions so I'm now in discussion with Mike Sokol, author of the No Shock Zone to try to clarify just what all this means. Frankly, with the amount of interest in surge protection and EMS growing I'm surprised that more haven't also questioned Progressive more aggressively and seem to be willing to simply plug in under the assumption all is well, regardless of just which power source they're using. :h

Removing a portable EMS from the circuit when using a genset or inverter as source power is the easiest and most obvious solution to avoiding any damage to the EMS. However, one can likewise easily install a hard wire unit so it too is quickly and easily removed from the system by installing it with 30 amp connectors. Some prefer 30 amp twist lock, I used standard 30 amp RV connectors simply because i had a few on hand in my workshop. I can have my Progressive EMS-HW30C disconnected in seconds, just as I could a portable unit, but with the additional features offered only with the hard wire version. :B

I was told the same thing when I called Progressive Industries.

FWIW, I've been using a pure sine wave inverter and inverter generator (with bonding plug) with my hard-wired EMS-HW30C for 2 years with no issues.

I take it you had plans to use a modified sine wave inverter?

MrWizard wrote:
there is no MSW generator, unless it was early model/prototype of inverter generator and installed inverter with power pass thru, should be after the EMS
hard wired or portable

the only case it would not be, is when using the shore power plugged into the inverter, with a hard wired EMS

you just need to rethink your electrical setup

Well, not quite. Apparently some generators, the popular Yamaha EF2000iS being one, can under some circumstances produce an MSW signal that can destroy a Progressive Industries EMS unit, and is the reason the company has posted this warranty disclaimer on their website. And BTW, Honda did produce an MSW genset, the EX350 2-stroke. ;)

As for using an inverter, that's exactly what I'd like to do - feed the trailer "whole house" with my PSW inverter by plugging the trailer's main service cable into it's output, the current issue being this isn't advised by Progressive when that main service cable goes on to feed one of their EMS units which in turn feeds the trailer's 120 vac system. Yes, I can physically remove my EMS from the system when using the inverter (or my Honda EU2000i inverter genset) as source power but given a choice I'd rather not if I don't have to. I don't need to "rethink" my electrical setup, I would just like to have clarification from Progressive on exactly what is acceptable, what isn't, and most importantly why not. To date they've not been willing to provide that information. :(

otrfun wrote:
I take it you had plans to use a modified sine wave inverter?

I have a Morningstar 300w pure sine and, until I win the lottery so's to get a Magnum 2000w pure sine, I'm using a cheap Harbor Freight 1500w modified sine.

Morningstar should present no issues.
JMHO

Otherwise just connect the inverter power after the breaker panel with a transfer switch... no EMS.

SoundGuy wrote:
Apparently some generators, the popular Yamaha EF2000iS being one, can under some circumstances produce an MSW signal that can destroy a Progressive Industries EMS unit, and is the reason the company has posted this warranty disclaimer on their website. And BTW, Honda did produce an MSW genset, the EX350 2-stroke. ;)

As for using an inverter, that's exactly what I'd like to do - feed the trailer "whole house" with my PSW inverter by plugging the trailer's main service cable into it's output, the current issue being this isn't advised by Progressive when that main service cable goes on to feed one of their EMS units which in turn feeds the trailer's 120 vac system. Yes, I can physically remove my EMS from the system when using the inverter (or my Honda EU2000i inverter genset) as source power but given a choice I'd rather not if I don't have to. I don't need to "rethink" my electrical setup, I would just like to have clarification from Progressive on exactly what is acceptable, what isn't, and most importantly why not. To date they've not been willing to provide that information. :(

They're easing up on the generator ban I think. Don't know which Honda 2000 they were referring to but they're saying it's "OK" as long as it's ground/neutral bonded. They even sell a plug now to insure that so you don't have to use the EMS bypass switch.

The sharp square surge in a modified sine is what the surge board in the EMS can't handle. Maybe there are too many variables in pure sine inverters for them to KINDA say OK for use with them like they're doing with the generators.

smkettner wrote:
Morningstar should present no issues.
JMHO

Otherwise just connect the inverter power after the breaker panel with a transfer switch... no EMS.

Easier said than done now that everything's in the front passthrough.

Wow, I'm surprised about all the concern about this issue. Are there any confirmed failures caused by using a PSW inverter or inverter generator with a PI EMS?

Before I ran any non-commercial power sources thru my EMS I viewed the waveforms under no/full load first. They looked fine. Ideally I would have checked distortion with a distortion analyzer, but don't own one.

Again, no issues with my PI EMS after 2 years.

Not sure what I see. Two inverters?

How hard is it to pull romex to the breaker panel?