Are 50 amp to 30 amp plug converters reliable?

They are as reliable as any extension cord. I stayed at a 50A only site one time, I didn't have a 50A-30A adapter so the lady at the office loaned me one. It worked fine.

We have a 50A 5vr........

Over the past 7+ yrs we have connected to 50A, to 30A and to 15A using adapters.

Only issues is power management.......only being able to use available Watts

AT 120V
50A-----12,000 Watts (up to 6000W per leg)
30A------3,600 Watts
15A------1,800 Watts

Circuit breakers will let you know when you have exceeded available amperage.
50A CB at power pedestal or RV Main 50A breaker will trip when connected to 50A
30A CB at power pedestal will trip if 50A RV connected
30A CB in RV will trip when connected to 50A power (if 30A RV connected)
15A CB feeder breaker will trip when connected to house outlet/pedestal outlet

One way or other a circuit breaker will trip when amperage is exceeded.

So get good adapters (dog-bone type not puck type) and plug in.

based on someone here's advice I made an adapter using a 50 amp plug and two 30 amp pigtails so I could use the side that had the best current. and I have noticed a difference between the sides in certain situations.
bumpy

To the OP. Your adapter is connecting to one side of the 50A service to provide 110V to your unit. The 30A breaker in your panel is still the limiting factor, and that is OK.
Using the 50A to 30A adapter is actually a GOOD IDEA, even when 30A outlets are available as you usually get a better connection at the pedestal.
This is what I do with no problems.

These adapters are nothing but three wires from the 30A plug to a plug designed to have four wires (50A) but only three are used. About as simple as it gets.

I see no problem in using it. You are only going to get 30 amps. You are only using one 120 volt leg in the adapter.

We're new to RVing but I can tell you we have used 50 amp to 30 amp adapters on our boat in marinas all over the U.S. and Caribbean for 25 years and never any issues using an adapter. I have only used the adapter on the RV a few times, but no problems. I too would recommend getting a good quality adapter. Chuck

j-d wrote:
Not really an issue. The Cord-to-Adapter connection may get a little hotter than Cord-to-30A-Receptacle so be sure the contacts are clean.

Going the OTHER way, 50A coach to 30A pedestal, is very likely to overheat stuff, since the coach can present so much demand. I was afraid at first that was what you were working with.

As noted ^^^ your coach is plugged into 50A, but still protected inside with your 30A main breaker. No worries!

Actually, neither 50amp coach to 30amp pedestal or 50amp pedestal to 30 amp coach present any problems. There is a 30 amp breaker protecting the systems in both instances. In the example of 50amp coach to 30 amp breaker the breaker in the pedestal will protect the circuit. In the 30amp coach to 50 amp pedestal, the main breaker for the coach protects the circuits. The biggest problem with the 50amp coach to 30 amp breaker is the fact that the coach will have to manage electrical usage so as not to trip the pedestal breaker. That isn't a safety concern (unless the boogie man is waiting for you outside your rig) but it is a dang inconvenience.

Not really an issue. The Cord-to-Adapter connection may get a little hotter than Cord-to-30A-Receptacle so be sure the contacts are clean.

Going the OTHER way, 50A coach to 30A pedestal, is very likely to overheat stuff, since the coach can present so much demand. I was afraid at first that was what you were working with.

As noted ^^^ your coach is plugged into 50A, but still protected inside with your 30A main breaker. No worries!

If you have a good quality adapter you shouldn't have any problem.