Originally Posted by brookside
Actually I was talking about pulling from two different 15a circuits - since none of the appliances are 240v there should be no issue even if both 15a circuits you pull from are on the same phase. If you read the link back to the original post the OP installed a relay and a second 15a input for his trailer so he could draw on 2 x 15a circuits when available but that got me thinking in terms of simply making a Y adapter vs modifying your panel. Last two campsites I was at btw had no 30a, only 15a, but did in fact have two duplexes per post each with its own 15a breaker.
OP's original goal was to be able to run AC and microwave at the same time when presented with 2 x 15a circuit
Only safety issue would be if you only plugged one of the male 15a Edison's in - the unplugged one would be hot. Could come up with a work around for that when I have my morning coffee.
FYI - TQ electrician here as well.
You would have to turn off both breakers, plug in both plugs, and then turn the breakers on again.
You would also have to make sure that the two circuits are in phase. Also, if one (but not both) of the circuits have the hot and neutral reversed, there will be trouble. Either of those conditions will result in nasty fireworks. Before trying this, check the voltage between the hot side of each circuit.
0V In phase. OK
120V One line reversed. No good
240V Out of phase. No good
In the real world, I would be surprised if you draw more than 25 amps without tripping one or the other of the breakers. This is probably not a very good idea if you don't know exactly what you are doing.