Coach Electrical Power Questions

[Dave Porter]

I need an education about coach electrical power and what actions I could take if we find ourselves in a similar situation in the future.  Over Memorial Day weekend we were in a full campground connected to 50A service.  During the late afternoon, all power in the coach would intermittenly drop for 30-40 seconds, reappear for 5 minutes or so, then again drop.  Looking at the Aladdin system, it would report 115V on one leg, dropping to 109V while the other leg would report 109V dropping to 102V.  I tried the pedestal 30A service with no changes to the symptoms as whenever any leg reported 102V, power would drop in the entire coach, then reappear 40 seconds later.  The Aladdin would report losing a source of power.  During all this, I was only running one A/C, the TV and the refrigerator.  None of the readings from the Aladdin suggested I was ever drawing over 18A.  After the peak A/C demand time (later in the evening or early in the morning) all systems would work fine.  I talked to the campground owner and they didn’t have any other reports of similar issues.     Obviously I was experiencing a low voltage situation and “something” was dropping offline until voltage once again crossing some threshold.  This is where I need an education.  Where does the Aladdin measure the voltage?  Is it on the service entry side to the coach or on the output of the surge protector/transfer switch?  If I had taken readings at the pedastal, would I have seen the low voltage?   Any ideas what that “something” was that was dropping power in the coach?  Does the threshold where we lost power sound correct?  Were there any actions I could have taken to avoid being in this predicament?  And what potential damage may have been done to the coach and what should I be looking out for?

As always, many thanks for your thoughts.

[Wayne Tull]

You probably have power protection control device that is disconnecting power to protect your electrical system when power is to low or high. That's a good thing.

[Edward Buker]

David,

It looks to me like you were in a campground that had poor infastructure and the wiring could not handle the load. There is a small chance that the breaker, connections, and or outlet at your post could have played a role but those sources of voltage drop tend to be more intermittent in nature. I believe the dropped power was your protection circuitry cutting in to protect the coach. The air conditioning units are probably the most susceptible items in the coach of being damaged while running or starting on low voltage, with some electronics being next. Most likely nothing was damaged and you were protected by the actions that the monitoring system took. The Alladin was telling you that the current you were drawing at 18 amps was normal and that the voltage drop that you were getting was most likely dropping before it ever got to the campground post at your site. If this happens again take a meter or a plug in voltage monitor and measure the voltage at your post and I would venture to an adjacent site and measure there also to make sure that it is just not your post that has a problem. The 102V dropping of power is normal and attempting to protect the coach from brown out low voltage damage. I believe the campground owner was not being completely honest and likely knew that his infastructure was at fault. If you were near the end of the line in load sharing (last post on the wiring loop) you could have lower voltage than the rest of the folks on your leg and be more affected. The only choices you have are to cut more load at your coach by turning off the air (ug), move to another campground or site that is closer to a transformer that provides the power, or start the generator and run it during the severe load timeframe. I might opt for the last option if the voltage reached 106V or below while running air units.
Hope this helps.

Later Ed