"Vernon" wrote in message
...
Guys,

I am building a heavy "extension cord" intended to carry 50 amps not
more than 100' from our 200 amp power box to my van. Inside the van
will be a couple of welders and a plasma cutter.

The idea will be to move the van around the yard to where I need to do
welding or cutting so that I don't have to load and unload the
equipment constantly.

I am running AWG #4 four conductor wire. The power supply end of the
cord will plug into a 4 conductor (two hots, ground, and neutral) 50
amp plug protected by a 50 amp breaker located at the main power box.

The cord will terminates at a 100 amp weatherproof box that is screwed
to a 4' piece of 2x12. This "panel board" will be semi-permanently
affixed to the interior of the van - perhaps fastened to the back of
one of the bucket seats.

The panel box only has spaces for three 240v circuits. One of these
three will be a 50 amp plug controlled by a 50 amp breaker inside the
panel box. Another will be a 20 amp 220v circuit for my inverter
welder. It's the same plug configuration as for a 220v air
conditioning unit.

I wish to use the last of the three spaces for 2 pole circuit breaker
energizing a two gang box that will have two duplex 120v receptacles
(i.e. four 120v receptacles).

Rather than put these 120v plugs on 120v single pole breakers I would
prefer to split each leg of the double pole breaker to feed two of the
outlets.

Why? The only difference is the breakers are tied and trip together, which
is no advantage. Electrically, breakers on different stabs will balance the
same as on a double pole breaker.