Weird Wired Power Pedestal

[RedRollingRoadb]

Upon hooking up to electric I turned all breakers off, plugged in my 30 amp cord and turned on the breaker marked "30."

Went for a walk, etc. Couple of hours later wife went to turn on microwave and it had no power. I went to the power pedestal and reset 30 amp breaker with no results. Thinking I had confused the 20 amp with the 30 amp tried that. Nothing.

Unplugged cord and reinserted, again nothing.

Scratching my head I try above steps again thinking I must be overlooking the obvious. Nothing.

Then I flip the 50 amp DOUBLE pole breaker. Bingo. Why I did that I don't know, out of frustration I guess.

Whoa I think. Someone screwed up big time. Remember this is a 30 RV. I look again to see if I missed something. Did a second look in disbelieve there is NO fifty amp outlet in the pedestal.

Now I am getting a little nervous thinking I am going to see the smoke of burning electrical equipment that was only meant for 115 volts. Pulled the cord out and checked for the proper voltage, everything good except there is a 50 amp breaker instead of a 30.

Going to check a couple of empty sites in the morning to see what the have in the pedestal.

The DW just asked what I wanted for Christmas I said "Progressive Industries EMSHW30C Surge Protector, it is in the Amazon wish list." "There is also a transfer switch in there too." The explain what they are. Maybe if I am real good...

Beachside State Park, Oregon site 82. I wonder how many others have plugged into this site and never questioned its power setup? Sending a e-mail to the park system in the morning after I check a few other sites.

[RedRollingRoadb]

OK. Looked again and as I said there is a 50 amp double pole breaker and a single 15 amp and single 30 amp. One 30 amp outlet. No sign of ever being a 50 amp outlet.

As DrewE and beemerphile1 said both the 50 and 30, or 15, have to be turned on. Since the 50 is a double pole I have no idea if the 30 is wired into one and the 50 to the other. Plus I really don't care. There is 115 volts at the 30 amp outlet, and also the 15.

Took a quick look at three other pedestals and all were same setup. I had just never seen this before.

I do agree that lots of 30 amp outlets show signs of overheat and burnt contacts that is why I carry a 50 to 30 dogbone.

[D_E_Bishop]

I have never been there and I am not familiar with the pedestal but I was a licensed electrician in Oregon. They pretty much used the NEC as it is printed. Somewhere I remember the code saying as mentioned before, the pedestal must have a master breaker.

I don't think any Oregon licensed electrician would ever suggest using a cheater cable, 20 amp and 30 amp plugs to make fifty amps. The main is not required by code to be equivalent to the total of the individual circuit breakers.

[Pogoil]

I have noticed that many Oregon State parks have heat damaged 30 amp plugs in the past.

Pogoil.

[MEXICOWANDERER]

You have YOUR main breaker inside your rig.

It's a voltage question. Why not RIG UP YOUR OWN voltmeters by purchasing a repair PLUG for your type of shore power then gluing on volt meters, Glue on a strap to yank disconnect? This would be a nice Saturday Project.

[beemerphile1]

I'm guessing that the 50a is a main and feeds the 20a and the 30a. Should be fine.

[chuggs]

Power pedestal document

Page 25 of this document has a normal wiring schematic for a common 50/30/20 like the PM137 series...

...edit...oops I didn't see that you said there was no 50 amp outlet...my bad.

If you turn OFF the 50 amp breaker...and turn the 30 amp ON and the 20 amp ON...if you get no power from any outlet...

Then turn the 50 amp breaker ON...and everything works...

As a final measure...turn OFF each respective 30 amp and 20 amp breaker to see if it interrupts power to the individual outlets... Then it's wired correctly with a 50 amp limiter on the boxes bus bars...

[wa8yxm]

Sounds like it is wired as a primary service box instead of a sub panel.

What is the differnce

Here is a sub panel

Main power wire----- bus bar

Bus bar has both 20 and 30 amp breakers hooked to it

Here is a main panel

Main power wire----50 amp breaker----Bus Bar

Bus bar (As above) has 20 and 30 amp breakers hooked to it.

This is actually a good way to wire it, but it is more expensive and not needed.

[chuggs]

Btw...nothing should smoke... The results are the same as if you plugged your RV into a 50 amp outlet using a doggone adapter...which I have done many times. The RV's power center 30 amp breaker will trip if your camper draws too much power.

I'm wondering if someone uses that outlet to run a welder when there isn't a camper there...and they rigged the box for that purpose. It's not unusual to put larger breakers on smaller gauge wiring for welders due to the intermittent duty cycle. My welding outlet is labeled WELDER only! I have a 100 amp breaker to prevent nuisance trips when using the TIG welder... That's NOT to say I endorse anyone rigging an RV pedestal this way...

[chuggs]

I think somebody played with the wiring in the box.

I would have an electrician investigate...

If you know the model of the pedestals housing...Thier websites usually have the schematics for the wiring... Or it may be on a decal on the back of the access cover. If someone has mixed stuff up in there...I would make good and sure they used the proper guage wire.

My pedestal box came prewired...all I had do do was placed my service line and ground into the lugs and tighten them down.

Each outlet IS supposed to be controlled by it's respective breaker... Something is NOT right if the 50 amp breaker in the pedestal housing turns on the 30 amp outlet...

[darsben]

Some codes require a main breaker to shut of all power to a box. I suspect the pedestal has a 30 amp and a 15 0r 20 amp service which equals fifty amps and that is the main breaker for the box

[DrewE]

You're sure there's no 50A receptacle around? Maybe there was at some time.

Of course, it's not unusual when there is a 50A circuit (and a 30A circuit) to have the 50A breaker be a main and the 30A (and 20A, assuming there's one of those) fed from legs of the 50A internally. Probably either there is/was a 50A previously, or they wired the place with the place with an eye to upgrading the sites at some point in the future...but who in their right mind would go to all that much trouble and then not spend the extra $25 or whatever for a 50A socket?

At any rate, I expect you'll find you need both the 50A and the 30A breakers on to get power. No safety issues if that's the case (assuming the voltage and polarity are correct etc.); there's nothing in the electrical code that prevents having multiple breakers in series for a circuit, even when it's not particularly useful to do so.

[ed6713]

For a few bucks you can get a device that tests the circuit before you plug your cord in. It tests for a proper ground, correct wiring, etc.

Never Plug your RV in without testing the power first.

Tester

To use this to test the 30 amp plug, just plug this tester into a 20 amp to 30 amp connection.