I think I am beginning to understand why the NEC was at one time considering requiring GFCI protection on 120V, 30-amp RV park pedestals (grounds can be hazardous). My RV does trip a GFCI instantly. Mike has explained why this occurs with some RV’s. I do think it occurs with mine, because when my inverter is operating, it grounds the neutral and ground legs together. And when plugging into a GFCI receptacle, it immediately trips, as the inverter is testing for safe power before switching to shore power and opening that internal neutral ground connection. I think the ground and neutral connection made by the inverter is causing the GFCI to trip. When using a cheater plug to eliminate the ground connection to the GFCI, it no longer trips and is happy measuring equal currents through the line to neutral legs as that neutral ground connection is just another path for current to flow though the ground connection. And theoretically, with GFCI protection, a ground connection should not be needed, well, unless maybe to drain away static electrical charges. With GFCI protection, are grounds just more trouble than they are worth? Especially when needing to use a different kind of cheater plug with a floating neutral inverter generator to satisfy an EMS ground and allow power to pass?
If outlet testers test between neural and ground that would be different than a standard meter test of an outlet that tests hot to neutral and then hot to ground looking for a very similar result. I would say it's time to break out the meter on that questionable outlet.
To really know for sure, you need a digital meter and a reasonable load that can be switched between line/neutral and line/ground. I use a 600/1,200-watt electric space heater for diagnosing ground/bon impedance and such. But that's way beyond of scope of this newsletter since there's a lot of potential shock hazards created by this type of test.
Mike Sokol I know you test electrical properties but based on recent experience I'd like to suggest some environmental tests. We had our first campout this weekend and had trouble with our Progressive PT30X. When we arrived Friday and plugged in the PT30X showed 133+ volts and would not allow power. I have an outlet voltage display that I use in the camper and it showed 120V and so did my AstroAI meter. I tried again Saturday and it showed 120V but error P10, which is a blown surge circuit. I'm pretty sure we've not been in a thunderstorm with it yet as it and the camper are less that 2 yrs old.
What's strange is when I brought it in the house after the weekend I can hear a SLOSHING NOISE like there's water in the unit. That can't be good right? I've got to get with Progressive yet but thought I'd suggest testing for water tightness as these can be exposed to rain.
I was not happy and had to do without it this weekend.
I had the exact same issue with the same 50amp SurgeGuard I use for our Airstream. I also have a new high end Progressive and a 5 year old Surge Guard. The new SG, open ground, the other two no issues. The campground GM came right over and tested our pedestal which on his meter showed a random open ground if we moved the probes. Upon our return I contacted Southwire with all the above. The engineer I communicated with via voice and email said he was not surprised as the new versions SG are the “most sensitive” in the industry. He also sent me some information via email which looks interesting, however, I’ve not had time to review. We changed sites and the new SG also showed open ground and then clicked on as all was ok. The engineer said again he was not surprised.
Seems to me that if there were two problems, the testers could interpret them in different ways. I’d want to take my own voltage readings at the campground pedestals and try to make sense out of it although I too would tend to trust my surge protector, it could also have a fault so double checking with a voltmeter seems to me a must.
I think I am beginning to understand why the NEC was at one time considering requiring GFCI protection on 120V, 30-amp RV park pedestals (grounds can be hazardous). My RV does trip a GFCI instantly. Mike has explained why this occurs with some RV’s. I do think it occurs with mine, because when my inverter is operating, it grounds the neutral and ground legs together. And when plugging into a GFCI receptacle, it immediately trips, as the inverter is testing for safe power before switching to shore power and opening that internal neutral ground connection. I think the ground and neutral connection made by the inverter is causing the GFCI to trip. When using a cheater plug to eliminate the ground connection to the GFCI, it no longer trips and is happy measuring equal currents through the line to neutral legs as that neutral ground connection is just another path for current to flow though the ground connection. And theoretically, with GFCI protection, a ground connection should not be needed, well, unless maybe to drain away static electrical charges. With GFCI protection, are grounds just more trouble than they are worth? Especially when needing to use a different kind of cheater plug with a floating neutral inverter generator to satisfy an EMS ground and allow power to pass?
The only way to know for sure is to do a proper ground leakage test. It’s not too complicated, but it does need a few special test tools and gadgets.
If outlet testers test between neural and ground that would be different than a standard meter test of an outlet that tests hot to neutral and then hot to ground looking for a very similar result. I would say it's time to break out the meter on that questionable outlet.
To really know for sure, you need a digital meter and a reasonable load that can be switched between line/neutral and line/ground. I use a 600/1,200-watt electric space heater for diagnosing ground/bon impedance and such. But that's way beyond of scope of this newsletter since there's a lot of potential shock hazards created by this type of test.
Mike Sokol I know you test electrical properties but based on recent experience I'd like to suggest some environmental tests. We had our first campout this weekend and had trouble with our Progressive PT30X. When we arrived Friday and plugged in the PT30X showed 133+ volts and would not allow power. I have an outlet voltage display that I use in the camper and it showed 120V and so did my AstroAI meter. I tried again Saturday and it showed 120V but error P10, which is a blown surge circuit. I'm pretty sure we've not been in a thunderstorm with it yet as it and the camper are less that 2 yrs old.
What's strange is when I brought it in the house after the weekend I can hear a SLOSHING NOISE like there's water in the unit. That can't be good right? I've got to get with Progressive yet but thought I'd suggest testing for water tightness as these can be exposed to rain.
I was not happy and had to do without it this weekend.
I had the exact same issue with the same 50amp SurgeGuard I use for our Airstream. I also have a new high end Progressive and a 5 year old Surge Guard. The new SG, open ground, the other two no issues. The campground GM came right over and tested our pedestal which on his meter showed a random open ground if we moved the probes. Upon our return I contacted Southwire with all the above. The engineer I communicated with via voice and email said he was not surprised as the new versions SG are the “most sensitive” in the industry. He also sent me some information via email which looks interesting, however, I’ve not had time to review. We changed sites and the new SG also showed open ground and then clicked on as all was ok. The engineer said again he was not surprised.
Seems to me that if there were two problems, the testers could interpret them in different ways. I’d want to take my own voltage readings at the campground pedestals and try to make sense out of it although I too would tend to trust my surge protector, it could also have a fault so double checking with a voltmeter seems to me a must.