Connecting 50a to30a rv shore power cord

    I'm looking for a connector with 50a female and 30a male. The problem is I can't seem to find one where the 30a male end has a blade style locking ground prong, only round. This is to connect 2 shore power cords together. It would save me the cost of installing a 50a outlet.

Is this it?

https://www.rvupgradestore.com/RV-Generator-Adapters-p/55-3766.htm

You won't find the adapter you're looking for. A straight or L-shape ground pin indicates a NEMA 10-30R 120/240 volt socket.

The only available adapters convert the 50 amp socket to the 120 volt only NEMA TT-30 outlet, which is identical to the 10-30R except it's 120 volt only.

Don't try to mix and match the two.  Although they're physically identical except for the shape of the ground pin, the 10-30R has two hot leads and a combined ground and neutral.  The TT-30 has a single hot 120 volt line, a neutral and a ground.

Many people have inadvertantly applied 240 volts to their 120 volt 30 amp RV plug by ignoring the differences between the plugs.

50 amp RVs do use 120/240 volts, but it's with a separate full size neutral and ground.  Before you make your own adapter, be sure the 10-30R socket has a full neutral, not just a ground connection.

50A female to 30A twist lock, 3-prong male:

https://www.etrailer.com/RV-Wiring/Mighty-Cord/A10-G30350VP.html

But make sure you know what that 30A outlet produces, for the reasons Lou outlined.

A question from a clueless potential owner if you don't mind...

If your RV is equipped with 50a service does that mean you can't utilize external power from a site that only has 30a service?

Lou Schneider said:

You won't find the adapter you're looking for. A straight or L-shape ground pin indicates a NEMA 10-30R 120/240 volt socket.

The only available adapters convert the 50 amp socket to the 120 volt only NEMA TT-30 outlet, which is identical to the 10-30R except it's 120 volt only.

Don't try to mix and match the two.  Although they're physically identical except for the shape of the ground pin, the 10-30R has two hot leads and a combined ground and neutral.  The TT-30 has a single hot 120 volt line, a neutral and a ground.

Many people have inadvertantly applied 240 volts to their 120 volt 30 amp RV plug by ignoring the differences between the plugs.

50 amp RVs do use 120/240 volts, but it's with a separate full size neutral and ground.  Before you make your own adapter, be sure the 10-30R socket has a full neutral, not just a ground connection.

Click to expand...

jymbee said:

If your RV is equipped with 50a service does that mean you can't utilize external power from a site that only has 30a service?

Click to expand...

No, doesn?t mean that. Use a 50 to 30 ?dogbone? adapter

jymbee said:

A question from a clueless potential owner if you don't mind...

If your RV is equipped with 50a service does that mean you can't utilize external power from a site that only has 30a service?

Click to expand...

You can, 30 amp RV sockets are the 120 volt TT-30 with the ROUND ground pin.  Adapters are plentiful because these sockets are 120 volts only so there's no danger of sending excessive voltage into the RV.

If you're trying to adapt to another socket, like the similar looking NEMA 10-30R with an L shaped or straight ground pin you can wind up with conflicting voltages and there's a real possibility of sending 240 volts into the 120 volt RV circuits. 

Please consult an electrician if you have any doubts about the socket you're trying to adapt to.

I once started to make adapter to plug my RV into a NEMA 10-30R socket, fortunately I decided to open the socket and see how it was wired before I made the adapter.

The two diagonal pins were connected to 240 volts as I suspected, and each pin measured 120 volts to neutral or ground.  So far so good.  But when I opened the outlet box I found only two wires running to the socket.  The third "ground" pin I was considering using as the neutral to split the 240 volts into two 120 volt circuits didn't have an actual wire connected to it.  It was merely a safety ground and relied on the conduit and all the intermediate couplings to supply the return to the breaker box.

It's intended use was to feed an electric dryer, which used 240 volts for it's heating element, not 120 volt circuits.

It would NOT have been safe to try to adapt that outlet into the pair of 120 volt circuits required by an RV.  If there was a fault or loose connection anywhere along the line the exposed conduit would have shocked anyone who touched it.  And without a solid neutral connection the 120 volt circuits in the RV could have had up to 240 volts applied to them.

A 50A camper will accept  240V  50A power, which is split into two 120V  50A feeds to the power center.  4 wires, L1, L2, N, G.

A 30A camper accepts 120V  30A power  3 wires, L1, N, G.

A 50A camper can use 30A power.  The adapter splits the single 120V line to feed both sides of the 50V line.  You are limited to only 30Amps.

Likewise, you can feed either 50A or 30A from a 15A source with the adapter, with the similar amp limit.

My 50A camper is plugged into 20A circuit as we type.

The cord I'm linking to is only 1 foot long. IS a longer version of this what you want????

TT 30 plug 50 amp marinco outlet

If it is. then you can get a standard 30 amp cord. with wire ends on the RV end, and a 50 amp Marinco Outlet and cover and locking ring at most RV stores.

If I got it wrong the connector on the RV is a Marinco, most likely.. And well the rest you can get at Lowes et-al. .  Rv Stores will have both Plug and Socket or Marinas.