Strange electrical anomaly.

[jestal]

We recently stayed in a camp ground with full 50 amp service.

Plugged in the Surge Guard to the pedestal, it timed out and every thing seemed fine......for awhile. Refridgerator started acting funny. Every 1 to 3 minutes the ice-in-door trap door would open and snap shut. noted that the entire fridge was shutting off momentarily.

I have the little three light electrical testers plugged into several sockets inside and noticed the yellow power indicators flickering on two of them concurrent with the reefer resetting. An analog volt meter plugged in beside them would swing towards zero when this happened.



Plugged the reefer into an extension cord and plugged it into another receptacle under the kichen cabinet soffet where the tester showed no power loss.


Basically one leg of the 220 was dropping voltage to zero for a nano-second occasionally. Random and rare in occurance it would stay away for 1/2 hour and them flicker 2 or 3 times inside of 10 seconds.

Camp ground handy man and I pulled the pedestal apart, checked for corrosion, tightness of all connections and replaced the 220 50 amp breaker and the 50 amp receptacle. No joy, the problem persisted. Ran my extension cord to another pedestal and had the same problem.

Ended up with the handyman's truck, an electrician's truck, a second electrician's truck and a bucket truck from the local utility all onsite at the same time. The power dropout was so fast you would not see it on a digital VOM!! But it was there. Never did find the root cause of the problem.

I got by by plugging everything needed into a receptacle on the good leg of the shore power to avoid the power drop out.

I am convinced it was emanating from the city's transformer which was immediately adjacent to the power distribution station of the camp ground. The Surge Guard did not pick up the problem. I ended up on temporary feed from another transformer by using two 50 amp cords and the house cord.
the power company guys started dropping by and checking and re-checking the same things for 4 days and explaining it was not their problem.....duhhh

The problem was finally resolved by us checking out...LOL. The Campground insisted nothing was wrong and that it was our coach!


Just one more thing to worry about and file away for future reference when something acts up....it may be your shore power.

[Old-Biscuit]

"Ran my extension cord to another pedestal and had the same problem."

Did you even test your power cord......?
L1 or L2 blade, wire etc.....continuity test while wiggling/twisting

Did you open up your MAIN AC panel and check wiring, connections?

[MoHoGo]

Al, not sure where you are, but with the heat down in Arkansas during the day we would trip shore power breaker. At night, when it was cooler, everything would be fine. Once the pedestal breaker was replaced the problem went away. However, it was not so much the breaker but the connections from the bus connectors to the breaker that had fatigued.

For sure you will know once you get on 50 Amps at a new campground.

[VanDiemen23]

You are seeing a form of brownout, although low voltage is the usual form.

Surge protectors don't fix brownout.

A lot of electronic equipment is protected internally against reasonable amounts of surge (at least once!), but brownout can produce "sneak circuits" and cause all kinds of havoc.

To see the stuff you describe you need an analog meter or a scope, or a digital meter that has a plotting graphic display.

[ECRyder]

We just went through tracking down a varying voltage on one leg of our shore power. The voltage finally dropped below the 107 volts limit of the Progressive Industries protection and would not connect. The voltage shown on the PI meter was all over the place. I ended up tracing the voltage drop to the cord reel. Replacing the cord reel corrected the problem. Tearing apart the old reel showed the slip ring contactors almost completely burnt/corroded away and heavy pitting on the ring for the one leg. Just another idea.

[jestal]

uh...duh....yes I did. Over and over as it turns out. As each "expert" showed up to prove to me how stupid I was we went thru the procedure many times. They got well schooled and a piece of my mind for free. You should have been there...

As mentioned the problem was so fast that a DVM would not show it so the test light was the real proof power was being lost.

I also took the coach breaker box apart and checked all the breaker terminals and screws for tightness. Checked the cord reel as mentioned.

I took one of my 50 amp extension cords and shoved wire ends into each of the slots and hooked them up to a spare 110 receptacle that showed up from another camper. One plug was fed off one lug and the other off the other lug. This way I could plug the 220 connector into the pedestal and plug in the elcheapo voltage tester with the two yellow and one red light into either leg of the 220. Don't try this at home...... The tester lights would stay solid on the one terminal and occasionally blink off on the other....with both my spare cords and connected directly to the pedestal receptacle. There was little question as to where the problem lay and which leg of the 220 was dropping out randomly.




I ran my two extension cords to another 50 service that was powered by a different transformer and campground distribution panel. The power on that was clean so it was definitely on the one transformer and system we were parked at. This campground had been added onto and extended several times so the electrical was a bit of a puzzle.

We've had the coach plugged into another 50 service and everything in the coachwas fine for 24 hours. I realize I could have a problem still somewhere but the persistent voltage drop we experienced was not from the coach.

Originally Posted by Old-Biscuit

"Ran my extension cord to another pedestal and had the same problem."

Did you even test your power cord......?
L1 or L2 blade, wire etc.....continuity test while wiggling/twisting

Did you open up your MAIN AC panel and check wiring, connections?