L1 and Line 2 voltage reading different

[sun47me1208]

This started to happen today. Prior to today both Line 1 and line 2 have voltage reading on my Power Control System Central Monitor Panel approx the same L1-118V; L-2 118V. Today I noticed that the readout was L1- 136 V : L2 - 100 V. This is when I am plugged in to the Shore. I measured the shore power from my Surge protector/Transfer Switch and the in line coming from the CG power post was 119V and after the Surge/transfer sw was also 119V. I unplugged the shore power and started the generator. Both lines L1 and L2 reads 118V. L1 is also the line coming from the inverter charger ( I mean it is the only line that have power when I turn the inverter on L2 does not have power when inverter is turned on).


I am loss as to where to look next. I believe that it is not a wiring or circuit breaker because generator voltage on both lines are same reading. What I don't understand is the transfer Sw would have different reading (In vs out) if it is the transfer sw.

Does anyone have a similar or exact experience on this? Can the wizards in this group point me the the right direction?

By the way, the Monitor panel also display " Brown out" This is when L2 reads 97V

[corvetteSS]

I would bet that it is just a matter of how the campground is wired. If all the 30A sites are using one leg, and just a few 50A sites are using the other leg.
This is why you try to balance loads in your main panel (of your house) to try to have similar loading across both legs of power. If you take a voltmeter across the legs on the power connection of the campground, I suspect that it will measure the same as your control center. I dont think there is anything you can do about it.

[Jim_HiTek]

136 Vac is ABOVE the max electronic and most electrical devices are rated for. I'm having trouble understanding your post though.

The voltage at the CG post, both lines are 119? Or just one line?

"Today I noticed that the readout was L1- 136 V : L2 - 100 V. " But what does it read at the CG's receptacle for each leg?

I'm thinking it's the device doing the reading of 136 V that is the problem. It's above max and very few campgrounds just suddenly jump that high. If it's that high at the CG post, why isn't your surge/voltage protector shutting it down? After all, 136 is over the trip voltage by a bunch.

I could be reading your post wrong.

[shootist]

You have a bad neutral , most likely at the post. You’re going to burn stuff up if you continue to use it that way. It can go as high as 240 through your appliances.

[sun47me1208]

Thanks to all who replied. It is getting dark. I turn off my shore power for tonight. We are moving tomorrow to a different CG. I did measure shoreline at the post and both are 119V ref to ground. Another observation I had is I unplug my 50A Progressive Surge protector and plug RV directly to the CG power post. The Lower voltage is now L1 (85V) L2 (145V). I will find out tomorrow at the different CG if this issue follows, and post ..

My Surge/ ATS is TRC model 41260.
Thank you

[TacomaJoe]

I 2nd the bad neutral. Since you are good on your generator, I'd say the neutral issue between the transfer switch and post. You'll know more at a new spot because then you'll know if its you or the post. Neutral issues don't show up when there is no load so measuring the post before you plug in might not give the full story.

[wolfe10]

Originally Posted by TacomaJoe

I 2nd the bad neutral. Since you are good on your generator, I'd say the neutral issue between the transfer switch and post.

MAYBE.


Could also be on the park side. No amp draw on either L1 or L2 and voltage may check good. Load is more likely to turn up a voltage imbalance.


Certainly check that connection in your ATS and either shore power cord reel or connections to the coach inlet are clean and tight. This is just a basic annual maintenance item.

[Mudfrog]

Originally Posted by shootist

You have a bad neutral , most likely at the post. You’re going to burn stuff up if you continue to use it that way. It can go as high as 240 through your appliances.

Originally Posted by sun47me1208

Thanks to all who replied. It is getting dark. I turn off my shore power for tonight. We are moving tomorrow to a different CG. I did measure shoreline at the post and both are 119V ref to ground. Another observation I had is I unplug my 50A Progressive Surge protector and plug RV directly to the CG power post. The Lower voltage is now L1 (85V) L2 (145V). I will find out tomorrow at the different CG if this issue follows, and post ..

My Surge/ ATS is TRC model 41260.
Thank you

I agree, seems to point to a bad neutral on the campground's side. The OP may have gotten the bad numbers if he had taken the reading between hots and neutral.

[Persistent]

L1- 136 V : L2 - 100 V. This is when I am plugged in to the Shore. I measured the shore power from my Surge protector/Transfer Switch and the in line coming from the CG power post was 119V and after the Surge/transfer sw was also 119V. I unplugged the shore power and started the generator. Both lines L1 and L2 reads 118V.

Does anyone have a similar or exact experience on this? Can the wizards in this group point me the the right direction?

This a clear and classic case of a faulty neutral connection. If it gets worse, it can destroy 120 volt appliances including your inverter.

Voltages fluctuate when various combinations of 120 volt appliances turn "on" and "off". Voltage on one leg can theoretically go to 240 volt while the other goes to zero volts.

The surge protector should detect the problem and disconnect. If it does not, then loose or corroded connection between surge protector and main breaker box.

Or, the surge protector does not have the programming to detect the lost neutral.

Get it fixed quick or only use generator.

Possible Neutral Failures:
Pedestal neutral socket too loose or corroded.
Shore power cord plug neutral pin is loose or corroded.
Cord reel connections are loose or corroded.
Shore power shore power input connections loose or corroded.
Main neutral buss has loose or corroded connection.

[Persistent]

Originally Posted by sun47me1208

Thanks to all who replied. It is getting dark. I turn off my shore power for tonight. We are moving tomorrow to a different CG. I did measure shoreline at the post and both are 119V ref to ground. Another observation I had is I unplug my 50A Progressive Surge protector and plug RV directly to the CG power post. The Lower voltage is now L1 (85V) L2 (145V). I will find out tomorrow at the different CG if this issue follows, and post ..

My Surge/ ATS is TRC model 41260.
Thank you

The issue is not L1 or L2 to ground, it is L1 or L2 to neutral.

If the surge protector is plugged into the pedestal and it says one leg is low and the other is high, then it is the the pedestal connection.

[Gary RVRoamer]

That much voltage difference between L1 & L2 is almost surely a bad neutral, allowing the L1/L2 voltage to float as the load changes. That is a serious problem because the voltage can and will go very high or very low at times, enough to cause real damage.


A common cause is a damaged shore power cord, typically where the wires join the plug (outer end) or perhaps where the shore neutral connects to the auto transfer switch.

[96 Wideglide]

Originally Posted by sun47me1208

Another observation I had is I unplug my 50A Progressive Surge protector and plug RV directly to the CG power post.

Yeah, probably the last thing I would do if faced with that problem!

[sun47me1208]

Ok we have arrive to our new CG (San Francisco RV Resort) and have been plug in for at least 3 hours and I am happy to report that both L1 and L2 read the same 121V at 7A and 8A draw on each leg. I dont know what is the real culprit on this phenomenon but IDo not trust reading of voltage when not loaded. Anyway Thank you to all who answered.



If anyone is interested where we we camped when I have the issue it was at San Benito RV Campgrounds in Paicines, Ca. site 334.

[Alan_Hepburn]

Originally Posted by sun47me1208

If anyone is interested where we we camped when I have the issue it was at San Benito RV Campgrounds in Paicines, Ca. site 334.

Thanks for the heads-up - we camp there a lot! Did you mention it to the staff?