50amp RV on 30amp post getting PE4 errors, why?

[d2reid]

Hello electrically smart fellow campers. You know me, I still don't fully understand electricity. So I did a dumb thing tonight. I took my EMS out of line. It kept dropping service for a 2 minute reset showing a PE4, Low Voltage, error code. If I remember correctly it drops service at around 108V. I know 108V is really bad for air conditioners, but at this time we are not running A/C. Here is some more behavior information. When the power comes back on, and before the EMS enables, L1 and L2 are showing 120v and 122v. All good. But when the EMS activates the RV the L1 drops to 110 and L2 to 109. AMP draw is between 15 and 23. Well below the 30amp limit. Hmmm, watts going on here?

Ok, I know that when you put 50amp units on 30amp posts over and over again the breaker gets worn and build up resistance. Ranger here assures me they have replaced the breaker recently. It is not warm to the touch at anytime. I am not thinking I have a weak breaker.

Line drop from usage, that could be a possibility, we are strung out at the end of the line and I have no idea what else is connected. And it does tend to drop at times when other folks would be doing morning/evening chores/cooking etc.

I am pretty careful about balancing our electrical usage on a 30amp post. Water heater and Refrigerator on propane settings. A/C set so that only one would come on, if it all. But we still get the PE4 low voltage disconnect.

So I did the unthinkable tonight. I pulled the Progressive EMS out of the line.

I know, I am asking for trouble. But I have had Progressive EMS get finicky and/or go south before. We will still mind our W's and V's and be real careful with the A/C units. Tomorrow I will dig out the old analog V meter and plug it in to watch and see what happens. At this point, I am kind of thinking the Progressive EMS is acting up. Definitely out of warranty.

[Jlawles2]

Your voltage reading before the amp draw hits it may be higher. Remember as load increases voltage may decrease if wiring is not large enough.

As you stated, other items on the line increase usage or as you leg of feed (wiring not the breaker) warms up the voltage will drop (resistance increases as temperature of wiring increases).

Think of the camp ground wiring as an extension cord. Lets daisy chain 4 - 100ft cords together and at each junction there are 3 outlets. One gets used to extend the length, the other 2 are open for load. If all 4 cords are the same size (14 gauge average size for home owner) with no load, the voltage at each of the plugs will be relatively the same. Lets now start adding load at each connection. the closest to source connection should always have the highest voltage, then second will be second highest, etc. if at each branch the load applied is 4 amps (don't want to trip the breaker) connection 1 sees 16 amps connection 2 sees 12 amps, connection 3 sees 8 amps and the end (connection 4) sees 4 amps. Cord 1 will get warm or hot, cord 2 less, cord 3 less, and cord 4 may not see any temperature change.

Depending on how the sites are wired this could be the situation. If you are at connection 4 you see the most voltage swing. Likewise, to save money they probably downsized the wiring between each successive connection. So now you have a 12 gauge cord, a 14 gauge cord, and 2 16 gauge cords. The 12 is still overloaded due to length and total load., like wise with the 14, and the 3rd 16. The 4th 16 gauge is probably OK (except its under powered by the others).

Hope this is not too long winded or complicated.

[howson]

Good plan to verify w/meter. Pls update when c/w

[ncitro]

The voltage dropping that much when connected tells me there’s a problem in the park wiring. My guess would be a bad connection underground somewhere with high resistance. As you (and other on your line) increase their current draw the line is dropping voltage. This all assumes your EMS is reading properly obviously. Unfortunately not much you can do in this situation other than let the EMS do its job and disconnect you when the voltage drops.

[d2reid]

Your voltage reading before the amp draw hits it may be higher. Remember as load increases voltage may decrease if wiring is not large enough.
Hope this is not too long winded or complicated.

Excellent description and I do understand what you said.

The voltage dropping that much when connected tells me there’s a problem in the park wiring.

I mentioned the problem to the park ranger yesterday and he told me that they have had other complain about the problem. It's not something they are going to try and fix. I know that sounds shocking and irresponsible and normally would be except for the situation.

We do volunteer campground hosting. Where we are at a state park that needed a host to fill in for a month while one of the more permanent hosts recovers from surgery. As a result we ended up in the "other" camphost spot, the one that is rarely used. We move on in a week. While the managers of the state parks do there best to keep the parks in excellent condition there are times when they have to do without to stay within their annual budget. Fixing this utility line for one host is not very cost efficient for them. He will put in for special funding, a "project". It will get sent up the line to HQ, HQ will prioritize projects and either fund it or not. But a single volunteer site is pretty low priority.

In the mean time we get to enjoy a beautiful camp site. Now where did I put that darn voltmeter?

[d2reid]

Ok more data. There is a huge fluctuation in voltage and there is a correlation to what we are drawing. Something somewhere is acting as a resistor. It's tempting to do a hot wire test to see where the problem is, but that would be rude, so I will just manage our usage until we leave.


Pulling 6 amps



Pulling 16 amps



Pulling 3 amps

[TedS]

Looks like you are at the end of an undersized wire feed. A stepup transformer, autotransformer, would restore your voltage. You would then have a current limit. Can't get more power out than what is coming in.

[ncitro]

Ok more data. There is a huge fluctuation in voltage and there is a correlation to what we are drawing. Something somewhere is acting as a resistor. It's tempting to do a hot wire test to see where the problem is, but that would be rude, so I will just manage our usage until we leave.


Pulling 6 amps



Pulling 16 amps



Pulling 3 amps

Yep that sounds right. It’s a shame parks funding is where it is. Try to keep your current down, and keep your sensitive stuff off and should hopefully be okay

[d2reid]

A stepup transformer, autotransformer, would restore your voltage. You would then have a current limit. Can't get more power out than what is coming in.

I wish it so, but it's not going to happen. So as usual, we roll with the flow... get it current..flow...

Try to keep your current down,

I had an instant reaction to these words. I was trying to imagine a current suppression system... all I got was some smoke above my head from trying to think to hard. We know how to manage our electrical usage. It took years to learn. Living in an RV is not the same as living in a house. No A/C usage, no convection oven usage, no air fryer, hair dryer only when everything else is turned off. For some reason DW considers a hair dryer an essential system.

What's fun is to put the bagels in the toaster. Instead of cherry red elements they are kind of brownish, takes longer to toast a bagel...

[Jlawles2]

You may try opening the power post and checking the plug and breaker lugs for proper torque and corrosion. Depending on when the park was built it may have AL wire which will corrode in the plugs and breaker causing a multitude of problems.

[d2reid]

You may try opening the power post and checking the plug and breaker lugs for proper torque and corrosion. Depending on when the park was built it may have AL wire which will corrode in the plugs and breaker causing a multitude of problems.

I will give this a try today.

[Scott'n'Wendy]

I will give this a try today.

I would be surprised if they let you open the panel....I am also surprised they don't want/have the $$ to investigate. A significant voltage drop in wiring causes heat...heat can cause...fire..

At least you know it wasn't your EMS flaking out on you. It was doing it's job properly. Unlike the utility at the park.

[d2reid]

I would be surprised if they let you open the panel....I am also surprised they don't want/have the $$ to investigate.

I wasn't going to ask permission. I am a huge believer in personal responsibility. So if I open the panel and screw up it's on me. I believe they don't have the money. A huge part of state parks budget comes from summer revenue. Close the state parks down for most of the summer their budget gets hit hard. State managers have got bigger problems on their plate than underfunded state parks. So 2021 is going to be a skinny budget year for the state park systems, as well as many other whose life's have been impacted by the shutdown.
.

[Scott'n'Wendy]

I wasn't going to ask permission. I am a huge believer in personal responsibility.

And I have no issue with that...except you said in the first post you don't completely understand electricity. Remember, even with the breaker off, there is still power in the box. Be careful.

[Guest]

Unrelated: That paint job is amazing!

Related: I had this issue a couple years ago in a heat wave. EMS shut down and I began moving items to gas and watching the voltage like the crew of Apollo 13. Was able to salvage the trip since AC was essential. I believe the EMS saved my AC.

Jim