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Topic: L2 Voltage Way High (Read 1831 times) previous topic - next topic

L2 Voltage Way High

Thanks to the forum and a supportive community, I am able to troubleshoot many problems on my own. However, my "handyman" skills are the equivalent of a dancer with two left feet, especially when it comes to electrical which is subject I simply have a hard time grasping. My ability to search throughout this (and other) forums are usually successful at yielding results if they exist, but this one I cannot seem to find. If there is previous information out there on this subject, a link would be much appreciated!

I'll try to be brief as I believe the photo tells the story. Line 1 appears to be slightly low while Line 2 is way up in the stratosphere. This is on a 2000 U320 and is a recent development that popped up within the last few months. The issue occurs when connected to 50A shore power, and the issue is consistent from park to park and hookup to hookup. I do use an in-line surge protector at the 50A electrical outlet, and the voltage appears this way both with and without the surge protector in place. The voltage also reads this way both with and without a load (ie, both A/C units running + fridge + AquaHot etc). When running the generator, the voltage is correct around 110 on both L1 and L2.

First obvious question is: what is going on and what is the possible recommended resolution?

Next question: Can I continue to run my A/C units and other accessories with this irregular voltage showing?

Re: L2 Voltage Way High

Reply #1 –
Check your connections to the transfer switch and to the surge guard and see if that fixes it. I would first put a meter on the box and see what the box is putting out.

Re: L2 Voltage Way High

Reply #2 –
Also check your neutral wire.  This may be a problem that could grow.  Check voltages at different points in the connectivity.  Not sure how you are reading this anomaly, as it could also be your metering.  Make this a priority to follow up on.

Re: L2 Voltage Way High

Reply #3 –
Quote from: Barry & Cindy –
Also check your neutral wire.  This may be a problem that could grow.  Check voltages at different points in the connectivity.  Not sure how you are reading this anomaly, as it could also be your metering.  Make this a priority to follow up on.
If you loose the nuetral coming in, the voltage will seek a path, eventily rising to​ 240 volts and fry a bunch of stuff. Had this happen at my house. Disconnect asap.

Re: L2 Voltage Way High

Reply #4 –
As everyone has said it is a neutral problem.  If the plug in not a molded on one start there and check to make sure neutral connection is tight and shows no sign of corrosion.

If not there start going down the line. Plug on other side of cord, receptacle that the plug connects to in coach, then tranfer switch. Breaker box will be the last place to check since problem can not be past that point.

My guess is receptacle that the power cord is connected to. 

Need to find problem, it will not get better.

Re: L2 Voltage Way High

Reply #5 –
Quote from: codytayloe –
When running the generator, the voltage is correct around 110 on both L1 and L2.

With this info it should narrow your problem to between the male end of your power cord to your transfer switch. Inside your shore to generator transfer switch check closely your shore power neutral lugs and wire.  This area has been known to get a loose connection causing a mountain of problems.
 
Do you have a cord reel?  Pull the cover off your brush/commutator and check to see if you have a bad brush on you neutral leg.

Pamela & Mike

Re: L2 Voltage Way High

Reply #6 –
Here is the area of trouble in your reel to look for a bad connection.

Pamela & Mike

Re: L2 Voltage Way High

Reply #7 –
The ground pin on our shore power plug split and broke inside the molded plug head.  The pin pulled right out.  Caused all sorts of strange voltage issues before I noticed the broken pin.

This has been a relatively common issue with cables as coaches with stock shore power cables age.

I replaced plug with a new one from Progressive Industries and power readings have been fine.

Chris

Re: L2 Voltage Way High

Reply #8 –
Great information and will certainly get me pointed in the right direction!  I have shut off incoming external power to the coach until I am able to isolate and repair the issue.  I certainly don't want to start replacing A/C units.

Since the issue developed, I have been plugged in to a few different parks which leads me to believe it was somewhere in the coach and not with the power supply at the shore.  Since the voltage is fine with the generator running, I assumed that it was somewhere between the male plug head and another component. 

I do have a hose reel.  Again, I have disconnected the surge protector and plugged the coach directly into 50A with the same issue, so I can eliminate the surge protector and focus on other issues.  I will start with the male end of the plug head and inspect the ground and other connections.  I know the head was replaced years ago but the cord is assumed to be the same one that came with the coach.  From there, I will check the brush at the reel, transfer switch, and breaker box.  All this electrical is outside my comfort zone, which isn't saying much!  If I'm able to make the repair myself, it will be a huge victory!

Re: L2 Voltage Way High

Reply #9 –
Foretravel had a lot of generators wire only 110V so if running on generator that would not cause the voltage imbalance.  The problem can be on the neutral anywhere from end of cord to the connection in the breaker box.

Re: L2 Voltage Way High

Reply #10 –
Yup, no question with voltage of L1 95 and L2 145, you have a lost neutral somewhere.

DO NOT PLUG INTO A 50 AMP CONNECTION AGAIN UNTIL THIS IS FIXED, OR YOU COULD "LET THE SMOKE OUT" OF ANYTHING YOU RUN.

Places to check:
Male end of shore power cord
Female end of shore power cord or reel connection
ATS, both in and out
Main breaker box

Make sure all these are clean and tight before even plugging in to check it.

Re: L2 Voltage Way High

Reply #11 –
Cody,
As others have said, you (or someone with electrical knowledge) needs to verify L1 and L2 voltages with a multimeter or outlet tester at the shore power outlet, the ATS (Automatic Transfer Switch), the coach breaker panel on the foot of the bed and then downstream outlets. You may well find the 120 Vac power reasonable and correct at all of those places.
 
Abnormal on 50A shore power, normal on 30A shore power and generator, however, points to another problem.

The Foretravel Power Line Monitor itself is a high probability suspect with these indications.  Removing the (4) mounting screws and the power monitor reveals two male "extension cord style" plugs, simply plugged into a "split" duplex outlet behind the panel.  The duplex outlet is wired to L1 and L2 at the breaker panel.  If both sides of that duplex outlet are at reasonable, proper Vac, then you have identified the problem.  95Vac + 145Vac = 240Vac, divided by 2 = 120Vac, so the power panel has lost reference. One of the Power Monitor printed circuit board's very common failures (similar to the "polarity"neon bulb failures) is to lose neutral continuity on the board.  When the neutral fails on the board, one gets your indication.

If that is your case, talk with ForeForum Commercial Member, Jim Frerichs.  He can repair your polarity indicators and the circuit board failure.  The coach power will operate fine (without the monitor in place) while it is being repaired.

HTH,
Neal
 

Re: L2 Voltage Way High

Reply #12 –
I do actually own a voltage meter... which by no means suggests that I actually know how to use it! In fact, I have never used it nor do I know how to properly use it, but I want to broaden my experience and I am confident it is something I can figure out with the help of YouTube and a little reading. I have replaced a few electrical outlets and light fixtures around the house over the years with the help of YouTube (nothing major at all), and so far I haven't burned the place down!  I check my smoke detectors and sleep with one eye open for at least a night.

I do appreciate the responses and I want to isolate and repair the issue if it is within my capabilities.  As Neal pointed out, I have also questioned the accuracy of the Power Line Monitor itself.  Here's why... we were early/midway into a 28-day trip when the problem first occurred and likely didn't notice it immediately (as we were in one place for several nights) when it did occur.  Since we experienced no failure (or smoke) at the time, we rolled the dice and let it ride.  It was a gamble and likely not my finest judgement call, but we continued and completed the trip without incident.

I completely understand that this does not indicate everything is working normally or will continue to function normally.  I want the issue resolved so I can feel confident everything is functioning as designed.  The reason I use a surge protector today is because the coach took an unprotected surge years ago immediately upon plugging it in.  The appliances and A/C units did not go out immediately or even overnight, but nearly all (fridge, A/C units) have been replaced one at a time over the years and I blame their abbreviated life-span on that incident.  History may repeat itself due to my choice to press on with our trip, but hopefully not.

I had actually forgotten about it until yesterday.  The coach has been on 20A more recently just to maintain a battery charge (it reads L1=95 & L2=95 on 20A).  I put 50A to it yesterday and was reminded of the issue.  The best I can do is follow the advice of members here who are much more familiar with the subject than I.  Hopefully I'll be able to chase this down, get it resolved, and gain experience in the process (and hopefully before we leave again at the end of the month).

Re: L2 Voltage Way High

Reply #13 –
When you have a bad neutral and coach is connected to 50 amp service it is getting 240 volts,  120 volts on each leg, where when you are connected to 20 amp or 30 amp the coach is only getting 120 volts.  As long as you are connected to 30 or 20 amps you should not be able to burn anything up.

Where the problem come in is when you are connected to the 50 amp service. The neutral wire carries the imballce between the two phases. Say on L1 you are using 10 amps  and L2 you are using 5 amps then the neutral wire will have a 5 amp load on it.  If both L1 & L2 have a 10 amp load then you will have a 0 amp load on the neutral.  The problem come when there is a problem with the neutral  the voltage on each phase is determined by the loads on each phase.  To keep it simple if L1 has the AC running and L2 has very little running then the voltage on L1 is going to be less then what is on L2.  I have seen where a home looses the neutral the voltage on one leg around 195 volts & the other 45 volts.  As you can guess all of the electronics and bulbs on the 190 volts do not last very long.

I would go to Home Depot or Lowes and go buy a volt ohm meter or an amp probe.  If you have an amp probe it can do every thing the VOM can do and also measure amps .  Problem is if you plug back into the 50 amp power you are taking a chance of burning up items in your coach if there is a real problem  and the gauges were correct.

If you PM me I will give you my phone # and  I will try and walk you thru the trouble shooting process.

Re: L2 Voltage Way High

Reply #14 –
Quote from: turbojack –
....................I would go to Home Depot or Lowes and go buy a volt ohm meter or an amp probe................................. Problem is if you plug back into the 50 amp power you are taking a chance of burning up items in your coach if there is a real problem  and the gauges were correct. ...........................
Turbojack,

Cody already has a voltmeter.  He is just not confident in how to use it.

I agree with some of what you say regarding L1, L2 imbalance with an open neutral, but why overcomplicate the issue?  I don't believe that anything drastic will happen when he is on shore power.  And, he needs the shore power to establish the condition's presence and absence.

As I understand it,  Cody has had these symptoms for a while without any recent APPLIANCE failures (or any other electric distribution system anomalies) which points to L1 and L2 power probably being OK.  It's just that the Power Line Monitor has partially failed (as a possibility).  L1 and L2 being wrong on shore power, but L1 and L2 being correct with the Gen set also points to a Power Line Monitor partial fault.  With 20 or 30 amp connectors in use, both legs reading 95Vac (the loaded condition and open neutral voltage reference condition on the card), also reinforces the Power Line Monitor possibility.

It is less than a 5 minute operation to remove 4 screws, unplug the two Line Power Monitor plugs and read the voltage in the two outlets with a voltmeter.  If the two female outlets are both at or about (the expected) 120 Vac, then the problem has been established.  Repair or replace the Power Line Monitor.  And it is fine to run without the Power Line Monitor, short term, in the meantime.
HTH to less confusion,

Neal

Re: L2 Voltage Way High

Reply #15 –
Neal,

Certainly, if this is a monitor issue, no problem.

But, if voltage really is 95/145, he could do a LOT of damage.

That is why he needs to put a voltmeter in it to VERIFY voltage. Simply sticking the probes of the voltmeter into any "house-type" outlet will give him accurate voltage on one leg.

Re: L2 Voltage Way High

Reply #16 –
How about starting with a continuity check?  No voltage involved, and relatively simple.

Chris

Re: L2 Voltage Way High

Reply #17 –
The monitor showed L1=95 and L2=145 while testing L1=116 and L2=119 on the incoming wires behind the panel. turbojack was a tremendous help with the troubleshooting process and educating me on proper use of the voltage meter! I am relieved that I don't have to replace anything substantial. Thank you all for your valuable input!

Re: L2 Voltage Way High

Reply #18 –
Quote from: codytayloe –
.........The monitor showed L1=95 and L2=145 while testing L1=116 and L2=119 on the incoming wires behind the panel..............................
Hi Cody,

Great!  Glad that it worked out for you and we helped you find your culprit!  And again, I think that Jim Frerich, ForeForum commercial member and Foretravel Owner, might be able to help you out, unless you have a better plan.  I'm confident it would be less expensive than going to FOT for a new one (if they are even still available).

As I said at reply #12, once you know that you have proper voltage at the power pole and at the outlets, on both legs of the breaker box, it can be rather intimidating imagining that the Power Line Monitor itself is the problem: "everywhere else I have looked at AC voltage, the voltage has been OK, but the Power Line Monitor is only 1/2 OK?" (OK on Generator but not OK on Shore Power). 

But, it is really easy to check the monitor, once you understand how it is powered.  Many owners haven't ever looked behind that Power Line Monitor Panel to understand it.

I didn't see anyone else pointing you at the Power Line Monitor as a possibility, but it is a fairly common failure (yours is the third partial failure that I've seen like this in just the past 6 months).

Glad you're OK now,
Neal

Re: L2 Voltage Way High

Reply #19 –
Quote from: Neal Pillsbury –
I didn't see anyone else pointing you at the Power Line Monitor as a possibility, but it is a fairly common failure (yours is the third partial failure that I've seen like this in just the past 6 months).

I appreciate your suggestion and turns out you were spot on! Thanks again. I have reached out to Jim Frerich through PM regarding the repair process of the existing unit. I'd rather repair the one I have than shell out the bucks for a new one, if a new one is even available. Last time I couldn't source something (and before I was aware of the forum here) and had to source a part from FOT, I left with a pair of $237 wiper blades after my Motorcade discount.

turbojack spent well over an hour on the phone with me walking me through the troubleshooting. In reality, it didn't take us a great deal of time to find the culprit and he was very patient with me as I asked some pretty basic questions that I'm sure is common knowledge to most veterans. I only hope I am able to return the favor one day!