Reversed Polarity Indicator

[cthalfman]

I am currently in a slip at the Naples Motorcoach resort. We have stayed in the same slip (same power pedestal) less than a year ago.
I have a hard wired TRC HW-RV 50 surge guard in place and it shows no faults and is allowing power to flow through to the transfer switch.
I do however have a "reversed polarity" indicator light showing on my interior inverter power distribution panel.
This seems strange as my TRC documentation shows that it would shut down on reverse polarity or an open neutral.
Can anybody think of what might cause the "reversed polarity" indicator upstream from the TRC?
Everything appears to be functioning properly in the coach (both 120V TV/Fridge/etc. and 240V cook top as well as the charge side of the inverters).
I do not have my 50AMP extension cable with me to plug into the adjacent pedestal to see if it rectifies the problem.
I am reluctant to move over a slip unless somebody can think of a reason I should disconnect from this pedestal ASAP.


1350213503

[dale farley]

Chris,

Have you tried unplugging and plugging in again to see if it resets or still reads the same? Maybe it was just a glitch since your TRC isn't showing an error.

[cthalfman]

Dale, yes I have unplugged from the pedestal a few times to see if it would reset. The "Reversed Polarity" indicator light goes out as soon as I disconnect. As soon as I plug back into the pedestal the indicator lights up immediately.

[cthalfman]

I have read a post where a guy had a bad ground on a water heater (on a boat) and it caused his reverse polarity light to indicate. I am wondering if I have something similar happening with something that runs off shore power but not the inverters?

[JIM KELLER]

Does the voice annunciator give you a warning saying " Danger, Polarity is reversed. "

[DickB]

If you have a meter, disconnect the cable and measure the pedestal directly. I'd go from the frame (metal should be grounded) to the top and bottom. Both should be zero. Then left and right. Both should be 120. Then measure left to right. Should read 240. If they measure correctly the pedestal is wired right.

[JIM KELLER]

Chris, There was more to my reply this morning but for some reason it was not included in my Post. I'll try again. I had the same problem. Took months to figure it out. My voice annunciator would come on in the middle of the night and I would get up with a flashlight looking and smelling. It wasn't until it showed reversed polarity with the Generator running that I started to suspect a ground issue. My loose ground was at the ground bus bar right behind the meter panel above the door. It was actually the ground for the reversed polarity light causing the problem. There is another ground bus bar behind the TV above the drivers position.


Hope this helps.

[cthalfman]

Hi Jim, I did not pick up on your post last night and I did not have the voice messaging system turned on. I spent some time checking the ground and neutral side of all of the interior outlets on the bus as well as the chassis to be sure there was no voltage on any of them last night.

We unhooked and returned home this AM and put the bus in storage plugged into 50AMP service. The "reversed polarity" light has not indicated upon return.

I have to believe there was something going on with that pedestal in Naples. It seems strange to me the the TPC surge guard would not have picked it up but it would have appeared to have resolved itself by disconnecting from that one pedestal. I have never had it indicate before and now it does not after.

Thanks for the replies.

[cthalfman]

Jim, I think you nailed it here for us. We now have the "Reverse Polarity" indicator light on all of the time whether connected to shore power or running the generator. I am sure I have a loose ground, now I have to find it.


Chris, There was more to my reply this morning but for some reason it was not included in my Post. I'll try again. I had the same problem. Took months to figure it out. My voice annunciator would come on in the middle of the night and I would get up with a flashlight looking and smelling. It wasn't until it showed reversed polarity with the Generator running that I started to suspect a ground issue. My loose ground was at the ground bus bar right behind the meter panel above the door. It was actually the ground for the reversed polarity light causing the problem. There is another ground bus bar behind the TV above the drivers position.


Hope this helps.

[JIM KELLER]

Good Luck on this. Start with the Velcro attached gage panel above the entry door. Easy to remove and inspect. Let us know the outcome.

[BenC]

Another consideration is an item that is downstream of your Surge Guard...your power transfer switch. If you carefully check out this area both visually and with a multimeter to ensure you do not have a voltage reading on your neutral wiring, and that the contactor for neutral wiring looks unburnt, that the wiring does not show evidence of excess heating from bad connections, then you and I will both feel better about your coach's condition. Just an area I would suggest checking out...

[JIM KELLER]

Very Good suggestion Ben !

[John L]

Curious what happened here. My coach has that same verbal warning as well, as soon as I push the domestic battery connection main. I will check the ground bars behind door meter area and inside TV box asap. I don't know too much about the transfer yet but will check there too.

96 Country Coach XL40

[Gil_J]

A true reverse polarity on a 50A/240V circuit that was once good is nearly impossible. The problem is likely a poor nuetral or ground connection.

Are both voltmeters close to the same voltage. Monitor the voltage reading and turn on a high current 120V appliance, like one of your two hot water heater. You should see a slight decrese in voltage on one leg of power and no change with voltage on the other leg. The voltage on the other leg definately should not increase. This is an easy test for a poor nuetral.

Yes check the transfer switch, if you're comfortable doing so.