Re: L5-30 wire for 220V?
Tim, I'm not trying to start an argument here, but why would you think that an L6-30 would be wired with a neutral instead of a ground? If the venue was built by licensed electricians and inspected by a local governing authority, then it's wired with a ground. I mean, it's pretty obvious...green screw, it's tied to the metal mounting points, and AFAIK, code says green screws are for ground. Heck, if you were desperate, you could take the wall plate off and see what the wire connected to the ground screw looked like. Green or bare and you're good to go.
I'm not saying that someone couldn't make a mistake, but if I go into a venue with the assumption that all the power is wired wrong, even though it meters right, then I also better be prepared to bring a generator everywhere I go.
Also, neutral and ground would NOT meter the same unless you were metering close to the service entrance. As distance from the service entrance increases, the potential between neutral and ground will change, depending on how subpanels are arranged and what is drawing to neutral on the same circuit or circuits fed from the same subpanel as the receptacle in question.
Of course, metering hot to ground and hot to neutral could be pretty close, but I always meter neutral to ground to see what's going on there. In the case of this particular L6-30 (if I absolutely had to use it), I'd meter the ground slot to the box or another nearby ground reference to make sure it was at zero. Anything other than zero and there is something wrong.
