Low Voltage on One 50A Leg

[TechWriter]

In several campgrounds I've noticed that my 50A legs were "unbalanced". For example, unloaded, L1 at 105V and L2 at 117V.

What's causing this?

[time2roll]

TechWriter wrote:

time2roll wrote:
Poor connection or unbalanced load. If this is at the pedestal you will need the park to fix it or move or use your voltage booster.

Yep, it's at the pedestal. One leg goes low about 1 pm daily when all the ACs are on. Yep, I use a voltage booster.

Good to go, no worries.

[wa8yxm]

DrewE wrote:

Gdetrailer wrote:


Hence the reason OP is seeing the voltage mismatch..

Given that the pedestals would presumably all be wired identically, it would be very odd for a campground not to wire up half the pedestals in the loop with the two legs swapped from the other half of the pedestals, such that the 30A sockets would tend to balance each other out. There's nothing other than an arbitrarily chosen convention that makes one particular leg L1 rather than L0, after all.

Sense that makes however......

Have observed a park re-wiring several sites. Even lent a hand (Steading the posts while the park paid employee, a friend, shoveled dirt around it and tamped it down)

They ran a bunch of BLACK wires.. Now they kept track of N and G but the two hots were both black. all black. no way to tell 1 from 2 at the box. So it is likely some 30's are L1 and others l2
But it's possible all one or the other.

And in another park (two others actually) have observed electricians working on them. again both L's were black. And Black is Black (I want my baby bac... Opps that's a song)

[TechWriter]

time2roll wrote:
Poor connection or unbalanced load. If this is at the pedestal you will need the park to fix it or move or use your voltage booster.

Yep, it's at the pedestal. One leg goes low about 1 pm daily when all the ACs are on. Yep, I use a voltage booster.

[Acampingwewillg]

Bumpyroad wrote:

Acampingwewillgo wrote:
. A quick trip to pick up a new female and all was well with the world.

sounds about right.
bumpy

If only that was so easy!!!
I had to chuckle after reading it again:-)

[joelc]

Are you reading this at the post or do you have a built in voltage EMS inside your coach? As noted above you need the raw voltage without load. A few volts difference will not matter.

[Bumpyroad]

Acampingwewillgo wrote:
. A quick trip to pick up a new female and all was well with the world.

sounds about right.
bumpy

[Acampingwewillg]

Since I've had erratic measurements a time of two, check both ends of your cord set ....mine had a loose neutral connection on my female Marinco 50 amp plug. A loose connection which soon turned into a burnt connection resulting in no power to RV. A quick trip to pick up a new female and all was well with the world.

[beemerphile1]

Test your unit. Use an adapter to connect to a 30a service. Voltage on L1 and L2 should be identical, is it? If not, your unit might be adjustable.

[Roger10378]

OP states "in several campgrounds" so that makes it most likely the problem is in his unit. The fact that the higher number is close to nominal says there is something wrong on the side with the low number. I would be looking for a loose connection somewhere in the positive side.

[DrewE]

Gdetrailer wrote:

I suspect what the OP is seeing is an issue in the campgrounds electrical system coming from MORE 30A 120V usage..

Most pedestals will by default have the 30A 120V outlet on the SAME "Line" and most likely that default IS L1, and more folks will be hooked up to the 30A outlets..

Hence the reason OP is seeing the voltage mismatch..

Given that the pedestals would presumably all be wired identically, it would be very odd for a campground not to wire up half the pedestals in the loop with the two legs swapped from the other half of the pedestals, such that the 30A sockets would tend to balance each other out. There's nothing other than an arbitrarily chosen convention that makes one particular leg L1 rather than L0, after all.

[CA_Traveler]

camperdave wrote:
so as a 30a RVer, sounds like it may be worth carrying two 50a - 30a adapters, one for each line. Pick the one with the higher voltage. Anyone do that instead of plugging into the 30a receptacle?

It's common practice to use a 50/30 adapter for 30A RVs for better voltage.

However voltage continues to vary and a autoformer would be a better option.

[wa8yxm]

Generally this idicates a weak Neutral but it can happen that almost all the park is on one leg (the low one) YOu need multiple voltage meausurements
The Park outlet (Sadly it's hard to measure when plugged in but if the box has 20-3--50 measure the 20 and 30 (use a puck style adapter on the 30 and a plug in meter) as these are usually on different legs (not always)

The park distribution box is also a test point but .... for the park not you.

[pianotuna]

Camperdave,

You would have to "roll your own". If going that far--why not build a "break out box" so you could have twin 30 amp outlets, one for each "leg". I added breakers to my "box" as well.

[Bumpyroad]

camperdave wrote:
so as a 30a RVer, sounds like it may be worth carrying two 50a - 30a adapters, one for each line. Pick the one with the higher voltage. Anyone do that instead of plugging into the 30a receptacle?

at one time I was going to take my continuity tester to the RV stores and test the 30/50 amp pigtails to see if I could find two that were different but thought better of it. 🙂
you could of course make your own adapter.
bumpy