Electrical Gurus - 50 to 30 amp dog bones

[The Ice Man]

I have a 50 amp pedestal on my property and when other ASers visit I use a 50 to 30 dog bone.

If I need to remain hooked, or if I have two needy visitors at once, I'm wondering how dangerous, fatal, hair-brained (or what ever term suits your fancy) the following idea is:

The standard 50A pedestal is wired Ground, Hot "A," Common, Hot "B." If I create a "double dog bone" by wiring two 30 A females into one 50 A male, how much trouble am I looking at? I'm looking at Circuit "A" using "Hot A," shared common and shared Ground; and Circuit "B" using "Hot B," shared common and shared ground, realizing that "A" and "B" are 180 degrees out-of-phase. Similar to this:
https://www.amazon.com/Epicord-Adapt...ogbone+adapter

Why won't this work, bearing in mind I don't want to make crispy critters out of my friends?

Your views are appreciated.

[TG Twinkie]

Looks like the female ends are 20 amp.
It would be difficult to run AC's. Other than that, it should work.

[azflycaster]

This is what you want.
https://www.amazon.com/dp/B073WB5LBY...a-350338554146

We used 100+ of these at the Escanaba International Rally last year. Running AC was not a problem.

[mojoe7009]

Originally Posted by azflycaster

This is what you want.

https://www.amazon.com/dp/B073WB5LBY...a-350338554146



We used 100+ of these at the Escanaba International Rally last year. Running AC was not a problem.

Yep, use to carry one of these on my boat. I had two 30 amp inlets on the boat and used one of these to tap the 50 amp outlet at the marina. Worked like a champ for years.

[Al and Missy]

Originally Posted by The Ice Man

I have a 50 amp pedestal on my property and when other ASers visit I use a 50 to 30 dog bone.

If I need to remain hooked, or if I have two needy visitors at once, I'm wondering how dangerous, fatal, hair-brained (or what ever term suits your fancy) the following idea is:

The standard 50A pedestal is wired Ground, Hot "A," Common, Hot "B." If I create a "double dog bone" by wiring two 30 A females into one 50 A male, how much trouble am I looking at? I'm looking at Circuit "A" using "Hot A," shared common and shared Ground; and Circuit "B" using "Hot B," shared common and shared ground, realizing that "A" and "B" are 180 degrees out-of-phase. Similar to this:
https://www.amazon.com/Epicord-Adapt...ogbone+adapter

Why won't this work, bearing in mind I don't want to make crispy critters out of my friends?

Your views are appreciated.

In essence, that is what happens inside a trailer with 50A service, as long as it doesn't have 240V loads like a home stove or clothes dryer. It should work just fine, but get 30A receptacles, or buy the one suggested by Azflycaster.

Al

[The Ice Man]

Originally Posted by azflycaster

This is what you want.
https://www.amazon.com/dp/B073WB5LBY...a-350338554146

That's perfect. I thought I had searched Amazon and only found the 20 amp version. That's why I was thinking of making one up. This is ready made and costs less than the components bought individually.

Thanks!

[JohnTF]

Bad math , the 1st link gave 2 x 15amp = 30 amp outlets from 1 - 50amp .
The second link 2 x 30amp = 60amp , from 1 x 50 - overloaded by 10 amps .

[Al and Missy]

Originally Posted by JohnTF

Bad math , the 1st link gave 2 x 15amp = 30 amp outlets from 1 - 50amp .
The second link 2 x 30amp = 60amp , from 1 x 50 - overloaded by 10 amps .

Nope - Each leg of the 50 amp service is rated at 50 amps.

Al

[jimfa440]

Originally Posted by azflycaster

This is what you want.
https://www.amazon.com/dp/B073WB5LBY...a-350338554146

We used 100+ of these at the Escanaba International Rally last year. Running AC was not a problem.

Right on!

[dfbroussard]

Its done all the time, but you should be aware that you and/or your friends won't be properly protected electrically. You'll have a 50AMP breaker protecting a 30 Amp cable. Not really idea or to NEC code. If you swap out the 50Amp double pole breaker with a 30Amp double pole breaker it would be much safer (and meet code).

[AirstreamCSH]

Please read what dfbroussard said again.
The breaker exists to protect the wires. Not the equipment.
If you downsize the wires you need to downsize the breaker.

[azflycaster]

You do have 50 amps available at the pedestal, but the mainline breaker at the trailer is 30 amp.

[TG Twinkie]

There is no protection of wire between the pedestal and the panel inside the trailer.
The breaker in the trailer only protects what is downstream.

[cwf]

the power is there... why not just add the two 30 amp receptacles? only don't use the 50 if using any 30?

[rmkrum]

He may not have room in the box he has....

[AirstreamCSH]

Just for fun, check the size of the wire your pedestal was wired with. My RV panel has 50, 30 and 20 options. Could be they sized the wire for more and it’s just the panel that’s restricted.

[switz]

A RV power panel with 50-30-20 outlets has at least 80 amp wire coming in as the potential maximum load could be 80 amps on one leg and 70 amps on the other.

The 50 amp socket is in reality a 240Vac socket. However, an Airstream treats it like there are two individual 120Vac 50 amp outlets. For convenience, say one is leg A and the other is Leg B. In the typical panel, the 30 amp incoming power would be on Leg A and the 20 amp power would be on Leg B.

Thus if one has maximum load of 50 amps on both lets A and B, then adding a 30 amp load to leg A means the wiring upstream is seeing 80 amp power draw. Leg B is seeing a 70 amp power draw.

Most parks may have these panels wired with 100 amp capacity wiring coming into the box to help with voltage drop over distance.