Electrical Connection

[Tikvah]

I'm new to RV, but awhile back I picked up an electrical connector for the wall of the coach. But, now I'm at my first real RV park and I see the 30A plug is much different. 
Help me understand.

This is the connector I bought:



This is the plug in the park:

[belfert]

What you have is a 50 amp inlet for your coach.  That inlet will work just fine.  You simply need to buy a power cable that goes from the 50 amp inlet to an RV plug.  See http://www.marinco.com/product/50a-locking-powercord-plus%E2%84%A2-rv-cordset-25 for an example of the cord you need.  The Marinco brand cord is really nice, but very expensive and there are others who sell a compatible cord for quite a bit less.  I included a picture of a Marinco cord.

The receptacle you pictured is a 30 amp RV outlet.  You would need buy an adapter from 50 amp to 30 amp for around $20 to use a 30 amp plug with your 50 amp setup.

[Tikvah]

I think i always assumed that the 50A is always 220V.  I only use and need 120V.

Is the 50A 220V ?

[bevans6]

As noted, that looks to be a 50 amp 240 VAC Marinco inlet.  What you might do depends on if you have wired your coach for 240 VAC 50A service or for 120 VAC 30A service.  The plug on the post is going to always be either the standard 30mp RV plug as you have pictured, or a standard 50 amp 240 volt plug which is the same as a stove plug.  If you plan to use 30 amp 120 VAC for the coach I would buy a standard 10 gauge three wire RV power cord, cut the coach end off and install a female plug that matches your Marinco inlet, and wire black to black, white to white and green to green, and just ignore the red/purple looking terminal on the inlet and plug.   If you plan to wire the coach to use 240 VAC 50 amp service, I would buy a standard RV cord for 240 VAC 50 amp and wire it to the same Marinco plug, colour to colour as above, and buy a 50 amp to 30 amp converter dog-bone (because they look like a big bone) for adaption at the power post.

I see you just had another question.  In speaking of RV power standards, a 50 amp service is always a 240 volt based service, but it gets that way from having two 120 volt services.  You can look at it as two 120 volt 50 amp feeds.  So you can just use one of the feeds for 120 volt, and since 30 amp is lower than 50 amp anything you have that can support 50 amps is fine.  If you truly want to only use 120 VAC 30 amp service, just get a cord and wire it as I suggest above.  No harm in retaining and installing the 50 amp Marinco inlet as it will work fine, is no larger than their 30 amp unit and will keep future options for upgrades open.

Brian

[Tikvah]

I think I understand. I could use my existing female RV outlet, but only wire one side.  That would allow 50A of 120V.  My question then is, when I plug into the 50A 220V post, I assume I'll always know that I'm getting one side, and always getting the right contacts.  Seems easy, if the posts are always wired correctly and wired the same.
If only 30A is available on a post, I would use an adapter.

Picture below of the post I'm on now.  I assume this is standard.

[HighTechRedneck]

You are going to be here at the shop this week some time.  I can explain it and demonstrate it for you in person.

[Jerry32]

It is not always true that 50 amp is 340 volt as some parks are wired to 120 volt only as I was surprised to find in Yuma when I had a bad breaker I watched the repair connect the two legs in parallel to 125 volts Jerry

[Tikvah]

You are going to be here at the shop this week some time.  I can explain it and demonstrate it for you in person.

Are you local to Chattanooga?

[HighTechRedneck]

I am home based at the Choo Choo Garage

[chessie4905]

   That looks like a twistlock receptacle to me. I've never seen them in rv parks.

[luvrbus]

It is a twist lock at the bus connection Chessie when not hard wired sorta of a standard on RV's nowdays makes it a lot easier to roll up the heavy @$# 50 amp cord he should bite the bullet and buy a metal housing Marinco plug the plastic Galco are junk IMO

 He should have the standard rv male plug on one end of the cord to plug into the service box    

[Oonrahnjay]

  ... makes it a lot easier to roll up the heavy @$# 50 amp cord ...

    What's your experience with the cord reels for the shore cord, Clifford?

[bevans6]

Cord reels are very tough for the heavy 6 gauge or 8 gauge 4 wire cable for a 50 amp service, it's very hard to get the cord to wind back on smoothly.  Less of a problem for 3 wire 10 gauge.  One issue for both - if you put some current through a coiled cable you can get inductive heating and actually cause a melt-down.  I've seen it almost happen with a cheap extension cord that was being used coiled for 15 amp service.  If you read the fine print on many coiled cables they say not to use them unless fully extended.  I like the Marinco connector on the bus - but on the one hand you can lock your cable in a bay so no one can pull it out and cut it off in a rest stop or truck stop overnight, but on the other hand people can steal it easier when you are plugged in in a RV park...

Brian

[bansil]

what would scare me at first would be the 120V sticker slapped over the 240v sticker...probably hooked up wrong at first (like a drier in the house)...hope first users years ago checked it with a multi-meter