Electrical problem

[nrhareiner]

Good morning all, I have also posted this problem in the "Houston I think we have a problem forum"


Good morning all. I do not know whether to post this in "Sparky's corner" or here so I will post in both places.

Since last night a serious problem has started. I am plugged into same post as I have been for past month (at summer place on lake). Normal readings voltage around 117 each leg, amp draw usually around 27/leg. I have 2 trace 4000 inverters. Starting last night one leg voltage would go down to around 107 where bus would not allow power through. Interesting thing is that which leg would drop down would periodically change.

I run a progressive surge protector. Took that out of the equation, but the results stayed the same.

On generator while the voltage will fluctuate with amp draw, it always stays within expectable limits.

Yesterday before the problem started the circuit breaker popped for no reason. I have the inverters set to pull no more than 35 amps a side from the pedestal and that limit was never breached. The problem only started after that incident.

I have two pedestals on the site, and the problem happens no matter which pedestal I am plugged into at the moment.

Now for the question. Does this conversion (02 Vantare which was built in OK not FL) have some switch or other electrical device that is supposed to balance loads or draw that could have gone "crazy"? Could this be a 50 amp plug problem. I have inspected the outside of the plug that looks fine, but could it be a wiring problem on the inside of the plug?

Please, any suggestions appreciated.

[jimblu]

Try monitoring the voltage at the unused post with a handheld meter. If it drags down too, the park has a problem, which may just be too many other vehicles.

[nrhareiner]

Yes, the other pedestal on our site does drop down as well as the post we are plugged into. This I checked with a hand meter. However, the circuit runs from one pedestal to the other. The second pedestal is just a sub-pedestal to the main. I usually plug into the sub-pedestal by location. The main pedestal actually has breaker that feeds sub. They are not two separate lines coming in from the transformer.

I asked permission to plug into neighbors lot who is not here. So far except for one episode of blowing the circuit breaker (which may be older and weaker than marked) no other problem.

Any other suggestions and thank you

Hope this helps.

[truk4u]

Kim,

If you check voltage at the pedestal with a meter, you probably won't see low voltage because there is no amp load on the circuit. Here are a few ideas...

What kind of power is your neighbor getting?
The pedestal breaker could be going bad
Check to see if your power cord is getting hot at the plug
Your inverters should be set at 50 amps
Which circuit breaker tripped, the bus or pedestal?

If your experiencing the same heat as we are in the south, the park power may not be able to keep up with the severe usage.

[jimblu]

Did you try another pedestal in the park with the meter? With the heat it could be a brownout from all the AC, low voltage will make a breaker pop as the amperage goes up.

[nrhareiner]

The neighbors power is much better than mine. However, even moderate draw of amps causes significant lower voltage (20 amps changes voltage from 120 to 113). The legs are even though.

The power cord is warm but not hot at the pedestal.

My inverters are set to accept 45 amps, not 50 since here with 50 amp pull a side the breakers will always pop.

The circuit breaker that pops is always the pedestal, not the bus

The pedestal, including mine are fine with no load. Usually between 119 through 121.

The other information that I find curious is that as one leg voltage goes down, the other goes up. When one leg is at 106-107 the other is at 129-130. The legs do switch.

One idea is that my main pedestal breaker is going bad, with some arcing between legs. The other is that both of my receptacles one at each pedestal has a problem.

Any thoughts greatly appreciated.

[truk4u]

Sounds like you have two problems Kim. Your pedestal breakers may be weak and the park has a juice problem. If your neighbor drops to 113v with a 20 amp load, the park power is poor.

It's hard to get the park people to do anything unless they have someone who understands electrical. The usual response is they put a meter on the pedestal and see 120v and tell you it must be your bus, when in fact, under a load the power will be in the brownout range.

Keep us posted..

PS - If your at Table Rock, is Chris and Debbie there?

[garyde]

Hi Kim. I would ask the owners of the Park to have the Utility company come out and check the voltage at the source meter. Sometimes it is a Utility problem.
With older parks , with too many Coaches plugged in and using A/C at the same time the voltage can fluctuate as well.
Pedestals with their own utility meters should have the proper voltage, if this is what you have, the utility company is responsible.

[nrhareiner]

thanks to everyone

Debbie and Chris have sold their lot at ORA

I am having the utility people come out today and check. However as stated all they do is test a line with no draw against and say it is fine.

I know the breaker from next door is weak, it is a 50 amp and pops at 40 amps.

[JIM CHALOUPKA]

Kim, you could ask the power company for a "graphing/chart" recording test over a time period for volts and amps.

JIM

[Jon Wehrenberg]

Kim,

I'm late to this, but can add a few comments.

I would urge that you check the power at the pedestal breaker under load. If you are uncomfortable playing with open electrical circuits enlist the aid of the campground utility company or a maintenance man. I suggest this to get the bus out of the equation. My feel is the problem lies with the service to the pedestal or at the pedestal. Be especially mindful of any connection that might be loose. If you have an infrared thermometer aim it at the wires and connections from the CB to the 50 amp receptacle.

Breakers do get old and do begin to trip prematurely. However, a 50 amp breaker can handle a load of 40 amps all day long, but once you exceed 80% of a breaker's rating it can trip any time. This is from the various breaker suppliers that Jamestown Advance has. Relatively speaking the breakers are cheap so if you suspect the breaker it does not hurt to change it.

If I were to guess the voltage issue is probably related to the campground distribution and most likely is related to loose connections.

[BenC]

There are two MAJOR problems that plague most campgrounds and their maintenance team these days:

The first being that the power pedestal is most times (for the "bus sites") sitting in the direct sun. This causes the box the breaker is mounted in to get hot...or in some cases EXTREMELY hot. The household style breakers are made for mounting inside your house where temperatures are moderate. This style derates from the nameplate trip value for every degree above 70F. So, on an extremely hot southern summer day, the rating may actually be as low as 40 amps continuous before tripping. The other drawback to this style of breaker is that for every trip, the mechanics of the breaker suffer degradation and are no longer truly rated at what they were when new. This is a relatively small effect, except when you factor how many times coaches trip the breaker in just a short period of time. Even at 70F the breaker may only be "worth" a continuous current flow of 30-to-40 amps. When electricians design/wire each branch circuit within a home, the continuous loads and circuits of installed equipment are required to be 80% or less of the circuit protection trip rating, NEVER 100% like is expected of the shore power breaker on the post. So, if you are able to set your shore cord size (Trace SW4024 inverters) or at least monitor total current consumed, try to make sure you don't exceed 45 amps per AC leg.

The second issue that really plagues the campground maintenance guys is that these power pedestals are also exposed to the cold winter weather as well. Now, consider that different metals expand and contract at different rates with temperature swings, causing terminals and connections during the year to become loose and result in HIGH RESISTANCE connections, which cause excessive voltage drop (as the connections points act just like putting a resistor in the power path) for a small increase in current flow. If you complain, the send Billy Joe Bob out with a voltmeter, which he sticks in the recepticle; however, without the bus being plugged in, there is no current flow. Voltage looks fine to him and he blames the problem you the coach. Plug the coach in and obtain a good current flow for the guy so he can see that it is his problem, not yours.

Hope these considerations help.

Ben @ Coach Worx

[Jon Wehrenberg]

I am pleased to see Ben echo my comments because his electrical expertise is unmatched.

One comment from a manufacturer's perspective may help you understand why neither of us is looking at a coach problem. The tightening specs for the electrical comments are part of the standards for certification for UL 231 which these boxes are to comply. A brand new box will have the electrical connections loosen by the time the product reaches the customer. Part of the reason is not temperature related, but the fact that some of the materials used "cold flow". They are tight when produced, but that pressure applied to them is reduced as the copper and aluminum components flow as that pressure is maintained relaxing the tightness.

Also as Ben points out the circuit breakers as designed are not to be used as disconnects, they are not designed to function that way, and as they are switched, sometimes daily, the arcing across the contacts creates resistance and that affects current flow. I have had to change circuit breakers that have failed within weeks of being put in use in a campground. But until the UL standards change to require a separate switch that can handle frequent on-off cycles the competitive nature of the business will assure manufacturers will not be addressing this issue.

[nrhareiner]

Thanks to all that have replied.

Jon, I friend who was an electrician is due back here today and is going to check the breaker/box under load. I did not want to start to tear the box apart, and not comfortable testing the circuit under load.

Ben, thank you for the comments, I agree with all of them.

Jim, if we do not find the problem today, then I will call the local electrical company and get that graph/chart.

I do not feel it is a bus problem since it works fine on my neighbors pedestal. The tripping of his breakers is due to age, condition. The problem at my site is the amp/voltage problem.

If I missed anyone in the thanks, sorry but again thanks to everyone.

[Jon Wehrenberg]

Kim,

I don't know if the campground did home runs to a distribution box or loop fed the pedestals, but have your electrician measure power at the power outlet bus bar and at the receptacle connections. If the voltages are low and the same the problem lies with the campground distribution (or the lugs at the feed to the pedestal). If the voltages are high at the bus bar, but low at the receptacle look for poor connections at the stabs off the bus bar from corrosion, poor terminal connections, or even corrosion on your plug at the receptacle.

If the problem is in the distibution box of the campground you will know easily enough. A breaker with resistance across the contacts either at the box or the campground distribution panel is going to get hot. That's where an infrared temperature gun will help.

[flloyd]

Funny, but I'm having nearly the same problem here in a small MN campground. We're in Detroit Lakes, a smallish community and are staying at Country Campground. Their electrical system is fairly new with each pedestal having the customary 50/30/20 setup.

When I first arrived, I pulled into a nice spot, shut down and plugged in. Turned all 4 AC's on (it was over 80 and humid), and within minutes the 50A pedestal breaker blew. I tried again with just 2 AC's and again, the breaker blew. Then, I went to one AC unit, and yes, the breaker blew.

Upon examining the pedestal, the 50A breaker was quite warm to the touch. This suggests a lot of things, including loose connections inside the box. I requested another campsite and although the owner balked saying "we've had lots of big (non-bus) coaches in there and one just left yesterday...".

I moved to an adjacent site, 2 down, and the breakers held all night. I ran just 2 AC/s just be sure that we had _some_ cooling.

A few days later I returned to the same campsite and got their prime, end lot where a 38 ft Monaco had been sitting before. Oddly, this pedestal had a watt-hour meter on it, making it unique. Again, this one started blowing breakers. When I went down to the office to request another space, the management was livid. I had paid 4 days in advance and so, grumbling, they gave me another spot, this one closer to the main feed. It worked. No blown breaker. They also reported to me that my coach used an amazing 16 "kilowatts" (KWH) of power during the couple of hours use that I got from the metered spot. I tried to explain that at 50 amps, up to 12 KWH PER HOUR is possible. That flew past him like a speeding freight train.

The management is certain that there is something wrong with my coach because none of the other "big rigs" have a problem. I've been on the road for nearly a month and in about a half a dozen other campgrounds with no problems whatsoever. That's the last they will discuss it. Case closed, the big Prevost has a problem (in their mind).

Funny thing: This morning I saw the park manager walking down the path from the other end carrying a large screwdriver and a 50A breaker in hand. I decided that discretion being the better part of valor, I will not discuss it with him.

Now I do have a problem. My left side panel ammeter is hosed. It reads about 2.5x the actual load (as best as I can tell) and fluctuates a lot. I really feel I need this ammeter and I'm unsure as to what to do. John suggested that it could be accessed by unscrewing the front panel plate. If that's the case then I'm willing to do it.

[dale farley]

We stayed in a campground just North of Nashville Sunday night, and my surge protector would not let power through because of an open ground. The next one I moved to was marginal at 111 volts on each leg.

[nrhareiner]

Still no answer. Had friend who is an electrician look at pedestal. He did not find problem on campground side, but is suspicious of the electrical company side (from transformer to pedestal). I am waiting for the electric company to pay a visit.

[nrhareiner]

OK, we have an answer. The electrical company finally showed up late yesterday. One of the wires from the transformer to the pedestal was loose. They tightened the wire and the problem is gone.

Thanks to everyone for the help, as always it shows how valuable our POG membership is to all of themembers.