Large voltage drop in 30 Amp Service Mobile Home

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  #1  
Old 08-18-20, 12:47 AM
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Lightbulb Large voltage drop in 30 Amp Service Mobile Home

We have a vacation residence (Mobile Home) at a lake front community in Ontario, Canada. Each lot has a meter with 30 Amp service and its own meter. All RV's or Mobile homes have a standard 30 Amp RV plug that plugs in in the receptacle under the lot's meter.

In our case, the 30 amp RV plug runs into the Mobile home and into the home's electrical panel. On the left side of the box is a single 30 amp breaker for the whole house. On the right side lug is the breakers for each of the circuits. The house is about 800 sqft and has 8 circuits.

THE PROBLEM
The problem is a significant voltage drop when each appliance is turned on. I know I only have 30 amps total to work with, but from my limited electrical understanding, the voltage should not drop significantly with load amps, correct?

We have a brand new LG portable air conditioner that is rated 115v, 1350 max watts and 11 max amps. It is one of the new ones with built-in invertor for its DC compressor.

All lights in the house are modern LED 6w bulbs. Both bathrooms and 2 wall sconce's in the living room have 6w LED Edison bulbs. (8 Edison bulbs total in house)

When everything in the house is off except the Edison bulbs, they are very bright. But as soon as you turn on the A/C, they get dimmer. If you add a second appliance (it doesn't matter what....microwave, dryer, toaster, floor fan) the bulbs get so dim they don't offer any useful light...even though they are on their own circuit that is separate from the appliances.

I have tested various circuits with my digital multi-meter and found that we are loosing significant voltage on ALL circuits as appliances are turned on. The Edison bulbs are the most sensitive, however the normal LED bulbs in the ceiling lights and lamps have a much higher tolerance, but still dim once a few appliances are on.

Important to note is that I have NEVER tripped any individual or the main breakers which is correct behaviour. While I am sure I get very close to 30 amps, we don't have that many items to put it over.

Tonight I did some testing of the voltage drops at midnight to eliminate the idea that we are not getting enough voltage from the park...most people are asleep and not using power on a weekday midnight. Here are my results (Note, voltage is the same across every circuit)

Everything off except 3 Edison bulbs in bathroom: 122 v = Lights bright
Add: Turn on A/C unit: drops to 112v = Lights slightly dim
Add: Turn on compact dryer: drops to 101v = Lights dim but still some light
Add: Turn on small single element toaster OR microwave: drops to 91v = Lights barely glow, no useable light
OR: Turn on BOTH toaster AND microwave: drops to 85v = lights completely off

ASSUMPTIONS
I've researched this a fair amount before posting. The most similar problem I have read about is a loose/open/lost neutral condition. In this scenario, one side of the panel box lugs (one with load) will dip in voltage and the other side will increase. In my case I've only got 1 side (the other has the single breaker for the whole house). I can't pull the panel cover off tonight and test lugs behind the panel as my wife is sleeping there now, but I will do so tomorrow. I wanted to go ahead and get this posted so you guys could make some recommendations of further tests by the time I get to that tomorrow.

Or is this voltage drop expected for such a small service? My neighbours don't have dimming lights when they have their A/C and toaster/dryer/mwave on so I think I have a problem.

One last note...as I said before, I did this voltage test at midnight tonight so that I could eliminate dirty/brown power from the meter since no one is using much and its a cool August Canadian night (14 C), so no other A/C's running in the park. But I will say that the lights did not dim as much when I turned just the A/C. When I tested earlier in the day, they did dim considerably more when I turned JUST the A/C on with nothing else running. So there is that....

Let me know what you gurus think and what testing steps I should take next, especially to test for a possible lost neutral.
 
  #2  
Old 08-18-20, 07:15 AM
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It could be a loose connection in the meter/plug setup. Is there another post close enough to move you cord and test again?
 
  #3  
Old 08-18-20, 08:05 AM
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Sounds like you have a loose or poor/corroded connection somewhere is the line.

It may be obvious when you look re: discoloration and/or melted insulation.

 
  #4  
Old 08-18-20, 10:10 AM
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Thanks guys. I have a 50 foot RV30 extension cable for the generator for when the power goes out. I can use it to plug into another meter next door. Thats a great idea. The corrosion could of course be inside my wiring though...
 
  #5  
Old 08-18-20, 10:35 AM
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Is this a 120/240 volt @ 30 amps service or a 120 volt only @ 30 amps service (yes they exist) ?

Most likely there is a loose connecction somewhere.

All other conditions being normal, if you overload a circuit or service you will almost always trip a breaker before you notice more than 10 percent voltage drop.

For a 120 volt only service a lost neutral does not present more problems compared with a lost hot. A 120 volt only Canadian or U.S. service has the usual ground and neutral but only one hot.

Have you measured the voltage at the panel, after taking off the front panel? With just 30 amps coming in measuring voltage at the big lugs is not more hazardous than measuring at the breaker terminals. But you still have to be careful not to not let meter probes poke between two different closely spaced terminals or other metal parts and cause a short circuit.


 
  #6  
Old 08-18-20, 10:39 AM
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Since it affects all the circuits it is probably before the actual wiring in the mobile home so in the panel or before it.
 
  #7  
Old 08-18-20, 10:51 AM
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Its a 120v 30a service as I understand is standard in RV/Mobile home communities.

We may be getting somewhere...I just pulled the plug out of the meter receptacle. The prongs are corroded and rubber around the prongs is slightly melted. Head of plug is not "hot" but pretty warm to touch.

I guess my next step is to replace the plug. The meter and receptacle was replaced just 2-3 years ago, its a newish looking Leviton receptacle. What are the chances the receptacle is corroded as well?

See pic:
 
  #8  
Old 08-18-20, 11:27 AM
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Yes that plug and probably the receptacle should be replaced. That is very likely the source of your problems.
 
  #9  
Old 08-18-20, 02:03 PM
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You don't say where you are measuring the voltage. If the measured voltage is at the input to receptacle below the meter, the RV park or poco has a problem. If it's at the input to the breaker panel, the extension cabling to the meter is the problem. If it's at the outlet in the RV, the outlet connection or the cabling to the breaker is the problem.
 
  #10  
Old 08-18-20, 07:41 PM
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Since this is a 120 volt only system it will not be an open neutral. I suspect you are on the right track with replacing that plug and receptacle.
 
 

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