Low voltage campground.

Cavie

Senior Member
Location
SW Florida
Is the 1.4V N-G with the transformer unloaded and then it goes to 17.5V with loading applied? Is so that would be due to voltage drop on the neutral conductor from carrying the load current.
Or are you comparing the N-G voltage before the transformer and after the transformer when it's loaded in both of those measurements?
If it's the second case you're probably boosting on the neutral side instead of the line side. Measure from the line input of the autotransformer to its line output. You should see the amount of voltage boost. If the voltage measured across the line in and line out is very small then you may be boosting the neutral side instead.

It is 1.4 at the ped. in front of the transformer. 17.5 after the transformer. Very light load. Just the RV converter and a TV. Transformer is spliced into the RV shore power cord. I can not plug in without it. I need to now the safety ramifications of this 30 volt difference between L1 and L2. Also is there an KWH cost involved this as I am paying the electric bill? Not much transformer knowledge. 50 years residential experience. not much use for transformers.
 

Cavie

Senior Member
Location
SW Florida
Is the 1.4V N-G with the transformer unloaded and then it goes to 17.5V with loading applied? Is so that would be due to voltage drop on the neutral conductor from carrying the load current.
Or are you comparing the N-G voltage before the transformer and after the transformer when it's loaded in both of those measurements?
If it's the second case you're probably boosting on the neutral side instead of the line side. Measure from the line input of the autotransformer to its line output. You should see the amount of voltage boost. If the voltage measured across the line in and line out is very small then you may be boosting the neutral side instead.
Line side L1 is boosting from 122 to 138 with about a 5 amp load.
 

synchro

Senior Member
Location
Chicago, IL
Occupation
EE
Do you have an extension cord you can plug into the 20A GFCI at the pedestal and then bring it inside to make voltage comparisons with the RV outlets?
If so, measure the voltage between the neutral of an RV outlet to the neutral of the extension cord.
Also measure the voltage from the hot side of an RV outlet to the neutral of the extension cord, and then compare it with the voltage from the hot to neutral on the RV outlet itself.
The reason for doing this is to help understand why you are seeing different N-G voltages on the pedestal and inside the RV. If you can do these two measurements with and without a load that would be even better.
These measurements shouldn't trip the GFCI if you use a high impedance digital voltmeter.
 

Eddie702

Licensed Electrician
Location
Western Massachusetts
Occupation
Electrician
Is this camp ground in Otis by chance? My Cousin is in a campground up there they had lighting hit a tree and burn off the ground to his trailer, lost his microwave, ac burned out some circuit boards. His wiring in the campground is all overhead though. He has told me some strange tails
 

Cavie

Senior Member
Location
SW Florida
Do you have an extension cord you can plug into the 20A GFCI at the pedestal and then bring it inside to make voltage comparisons with the RV outlets?
If so, measure the voltage between the neutral of an RV outlet to the neutral of the extension cord.
Also measure the voltage from the hot side of an RV outlet to the neutral of the extension cord, and then compare it with the voltage from the hot to neutral on the RV outlet itself.
The reason for doing this is to help understand why you are seeing different N-G voltages on the pedestal and inside the RV. If you can do these two measurements with and without a load that would be even better.
These measurements shouldn't trip the GFCI if you use a high impedance digital voltmeter.
Yes I could do that except my transformer is spliced into my shore power cord. It is boosting L1 15 volts. It is also boosting the N/G 4.5 to 17.5.

The camper is on L1 30A and the ped GFI is on L2 GFI 20a in all these comparisons. So far I have found 6 sites with the same problem. One site is using a Hughes Autoformer which boost the voltage 10 %. His voltage with the A/C on and going through the autoformer is only 109 volts.

At all sites. when you add load L1 goes down. L2 goes up. One site goes from L1 98 to L2 132. I have got a lot of camper attention. what does all this have to do with the cost of electricity.
 

Cavie

Senior Member
Location
SW Florida
Well,
the owner got wind of what I was doing through his son that I spoke with. Said I have no business touching his meters. Told him I have not opened anything. Just using wall plug in $10.00 meters. L2 in the ped, L1 and in the trailer' He said I was not a Master Electrician and had no business going around scaring people with this information that I know nothing about. He has been told in the past that I am Licensed Master Electrician. He does not hear that part. Seams to him that 98 volts on a roof top A/C is good to go.

The Mother to the family affair gave me the same riot act. Her BIL stays here also. He had no Idea and was thankful for my information. She said "He has 50 amps, you have 30. You don't know what you are talking about". BIL has a 50/30/20 PED. He is plugged into the 30 and she does not even know it. Been here for years. One camper with the autoformer got a $76.00 electric bill on a 30 foot 30 amp trailer with only 20 min runtime using the A/C.

Looks like I will be moving next year. Thanks for the info.
 

kwired

Electron manager
Location
NE Nebraska
excessively long neutral can trick you into thinking you have bad neutral.

more current neutral is carrying the more voltage drop it will have across it and this will impact what you see for line to neutral readings.

less loaded line will have less drop but the neutral already is at a different potential than it is when not loaded at all.

Worst case I run into was at a golf course. They had utility service to a location that had their irrigation well. At some time they ran a line underground from there to a maintenance shed. To make things worse they didn't take the straight path from A to B but rather followed trail that golf carts use - total run was about 1900'. They ran triplex aluminum URD cable 2-#2 and 1-#4.

I learned hard way on that one, I knew volt drop was an issue, but though there was a bad neutral, but there wasn't. Shop didn't have much for load, but even a 5 amp load caused differences in output of lights (everything was typically incandescent back when I witnessed this maybe about 20 years ago).

They didn't want to entertain any options I gave them at that time, probably still like that I am guessing.
 

hillbilly1

Senior Member
Location
Atlanta,Ga
excessively long neutral can trick you into thinking you have bad neutral.

more current neutral is carrying the more voltage drop it will have across it and this will impact what you see for line to neutral readings.

less loaded line will have less drop but the neutral already is at a different potential than it is when not loaded at all.

Worst case I run into was at a golf course. They had utility service to a location that had their irrigation well. At some time they ran a line underground from there to a maintenance shed. To make things worse they didn't take the straight path from A to B but rather followed trail that golf carts use - total run was about 1900'. They ran triplex aluminum URD cable 2-#2 and 1-#4.

I learned hard way on that one, I knew volt drop was an issue, but though there was a bad neutral, but there wasn't. Shop didn't have much for load, but even a 5 amp load caused differences in output of lights (everything was typically incandescent back when I witnessed this maybe about 20 years ago).

They didn't want to entertain any options I gave them at that time, probably still like that I am guessing.
I lost a bid due to that, they were putting fans at the holes, 1500’ average, Bid it with 3/0 triplex. 1 hp fans if I remember correctly. I think the other contractor bid it 10-2 uf. Never see the fans running............
 
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