30 amp to 50 amp adapter???

[GreenWave]

Originally Posted by Wolfe10

A 50/240 male to 30/120 female adapter merely connects ONE of the two hots on the male end to the hot on the female end (along with the neutral and ground).

Yep. That’s what I tried to say earlier. A major cord failure would have to occur in order to pass the full 50 amps.

[mitiempo]

Originally Posted by GreenWave

Yep. That’s what I tried to say earlier. A major cord failure would have to occur in order to pass the full 50 amps.

A 50 amp 120/240 outlet has 50 amps on each leg.

[CaptTom]

Good discussion. I want to come back to this point:

Originally Posted by redneckrob

The only edge case where this is any less safe than using a 30 amp plug in a 30 amp service is the extremely rare case where you have some kind of short between the 50 amp shore power breaker and the 30 amp breaker at the entrance to the boat AND the short is of the very unique kind that is more than 30 but less than 50 amps (since an actual short would trip the 50 amp shore breaker).

This is why standards require the internal breaker to be close to the power inlet.

Note that TWO very unlikely things need to happen. (1) a failure in that short section of wire, and (2) a failure which happens to draw just the right "Goldilocks" current to burn the wire but not trip the breaker. And it has to be sustained (no melting at the point of failure) for a long enough duration. A dead short will trip the 50A breaker pretty quickly.

[ItDepends]

It is not unheard of to have a waterproof box that contains a 30 Amp breaker with a male 50 Amp input and a female 30 amp outlet. This would be the safest way to connect a 30 Amp boat to a 50 Amp outlet. It’s rare, but should not be.