Follow-up to 15 + 30-amp Y-Adapters
Is there a 30 + 30-Amp to 50-amp Y-adapter?
Everyone
I had a number of questions about my article on why 15 + 30-amp Y adapters don’t work on pedestals with a GFCI 20-amp outlet. They instantly trip the 20-amp breaker as soon as any load is applied. The GFCI receptacle is not tripping from excessive current overload. This is due to a current imbalance over 5mA (that’s only 0.005 amperes), which is exactly what a GFCI is supposed to do.
Reread my 15 + 30-amp article below
Can a 15-amp + 30-amp to 50-amp adapter work?
Mike, I hope you are well. We met you at the Hershey RV show this year and I had a question as we are getting ready to pick up our new RV next week. Was looking to get this adapter and was wondering if I would cause problems with my 50 AMP RV if I used this? And if it is ok, would this give you 45 amps of power? Also, if the park only had 30 amp hooks up…
How about a 30 + 30-amp Y-Adapter?
Yes, that can possibly work. But both of the pedestal outlets must be wired with correct polarity. If one of them has a neutral/hot polarity reversal then there will be a HUGE short circuit with hundreds of amperes of fault current that will trip the 30-amp circuit breaker, and possibly vaporize part of your plug contacts.
Reread my 30 + 30-amp Y-Adapter article HERE
What does it all mean?
If you plan to use a Y-adapter to power your 50-amp RV, there’s no guarantee it will work. And it could possibly create dangerous short circuit currents if both pedestal outlets aren’t wired with correct polarity. So measure the pedestals carefully and proceed at your own risk.
Let’s play safe out there… Mike
Mike, it might help if you included one of your nice wiring diagrams to show the current paths that result in the neutral current imbalance with the 15 A + 30 A configuration you describe. It is not surprising but a bit hard to visualize how this happens. Will it happen every time or does it depend on how the pedestal is wired? With a 50A pedestal, I assume they need to use both phases but do we know with a 30A pedestal if the 30A and 20A (or 15A) outlets are wired from the same or different phases? My trailer only has a 30A electrical system so I have no experience working with a 50 A connections. Thinking about all of the possibilities makes my brain hurt!
Hi Mike and happy New Year. This is a great article series. Could you by chance continue it with a more detailed explanation of the polarity issue ( I would assume this is improper wiring at the panel) and also how to test for proper/improper polarity in this instance?