Community Forums

Steve43 · 08-26-2020, 08:02 AM

Problem . . Power from pole checks ok (3rd different pole in two campsites). EMS kept tripping on any load over two amps. Removed EMS from equation and wired directly to transfer switch. A surge protector attached to pole shows 3 green lights (meaning all is good) UNTIL I plug in for 50amp AND turn on something (think converter drawing 5 amps) - Surge protector then shows 1 red, 2 green - meaning neutral and l1 reversed.

So I metered all the incoming wires at the transfer switch. Both hot side and transfer side. Neutral to l1 - 122, Neutral to l2 - 123, l1 to l2 - 245, same readings to grnd. And neutral to Grnd shows about 1 volt. That is without anything plugged in. Now plug in the converter that turns the surge protector to red (l1, Neutral reversed) and I get same readings EXCEPT neutral to grind reads 13 volts!

So I am afraid to turn on anything else in the coach. I have checked all the wiring in the breaker panel and all is good. We have been on the road for three months and only two times did we have problems with power poles - went away when we changed campgrounds. But this time it hasn't gone away after changing campgrounds.

Everything appears to meter correctly until turning on something that draws amperage - I can run the two AC fans (each draws about 2 amps - and split on l1,l2) but anything more than that will have the surge protector showing l1 and neutral reversed.

I do have internal EMS with intellitec 760 shedder but never used on 30amp and all 'looks' good. No wiring changes or any other new loads added.

Help - it is hot here! <g> and there is no 20 amp outlet so I could run some fans by extension cord!

Thanks for any help . . Steve

Persistent · 08-26-2020, 08:20 AM

You have a neutral fault. The surge protector has saved your system. Do not use 50 amp 240 volts shore power until you get it fixed. This fault can cause 240 volts to be applied to 120 volt appliances.

The neutral to ground voltage rises when current flows because there is a high resistance neutral connection or the neutral connection is open altogether. I expect the problem is between the surge protector and shore power pedestal. At least it is between where you measured the voltage and pedestal.

Voltage on the neutral wire will change depending on what appliances are running and on which leg of the 240 volt source they are connected to.

I wish you good luck and happy trails ahead!

jacwjames · 08-26-2020, 08:25 AM

Easiest thing to do is get another power cord, you might borrow one, to see if that fixes the problem.

Steve43 · 08-26-2020, 03:35 PM

Well, still the same except I was able to get a 30 to 20amp cord so I can use extension cords and run some fans and a crock pot! I did check the power cord when I eliminated the EMS. Continuity check with nothing between neutral and ground. I check all the outlets (it did fry a power strip I was using in the washer/dryer cabinet).I can still run the ac fans and it does not show any voltage on the neutral/gnd but anything else just starts showing voltage between the two.

I don't know how to check where this could be happening? Do I turn off all power and start doing continuity checks throughout? I did do a continuity check at the coach side of the Transfer switch and got nothing. Everything works on generator but not allowed to run generator here in Myrtle Beach. Just don't know how to proceed. No one else (200/300 sites) appear to be having problems. How could power be bad all over Myrtle Beach?

Suggestions? Thanks, Steve

twinboat · 08-26-2020, 05:23 PM

Did you trip or have the washer/dryer breaker off ?

You may need that on for the load sheading to work properly.

Persistent · 08-27-2020, 06:39 AM

Steve,

The voltage from neutral to ground will appear to come and go. It will only appear when there is current in the neutral wire.

When connected to 240 volts AC, the neutral only carries current when leg 1 and leg 2 are not carrying the same current. The more the unbalance, the more current in the neutral and the higher the voltage will read. The voltage is only visible while current is flowing in one leg and not the other.

Where is the surge protector in your system? The defect is between the surge protector and the pedestal. Or, it could be in the pedestal itself.

The issue may or may not appear on a different plug. Does the pedestal have a 30 amp connector? You may be able to use a 30 amp 120 volt plug. The issue would show up as low voltage on a 30 amp circuit.

Low voltage would not damage your electronics. It could overheat an air conditioner motor. Check the voltage while running.

KanzKran · 08-27-2020, 07:11 AM

Quote:

Originally Posted by Steve43

Do I turn off all power and start doing continuity checks throughout? I did do a continuity check at the coach side of the Transfer switch and got nothing.

A continuity test won't show much, especially with a DMM. The 0.3 mA of current from my Fluke DMM (through another DMM reading current) will show continuity on almost anything, but says nothing about high resistance connections that make a big difference with whole number current values.