One of the reasons this topic (240 volt outlets) is so confusing, is that most electricians, even tho they KNOW, tend not to mention that
just having two "hots" and a ground does NOT necessarily get you 240 volts - household services nearly always have both 120 and 240 volts available at the breaker box - the 120 volts is EASY - grab EITHER "hot" in the box and a NEUTRAL and GROUND, and you have 120 volts.
(No, I don't mean actually GRAB 'em)
HOWEVER, to get 240 volts you need to understand that
those two "hots" coming into the breaker box are NOT THE SAME - they are OPPOSITE in phase (When ONE hot is going positive, the OTHER one is going NEGATIVE) so if you were to
measure BETWEEN the two hots, you would see 240 volts. This is the ONLY way you can get 240 volts - if you were to use the SAME "hot" to both "hot" leads on a device, you would still measure 120 volts to ground or neutral; but
you would see ZERO volts between the two "hots" - because they would be the SAME WIRE...
Pretty much ANYTHING that ONLY uses 240 volts, does NOT use a neutral; only a SAFETY ground. If working correctly, the device would NOT have current in its GROUND wire; it's only there so that the chassis of the device doesn't have voltage on it.
Newer devices, like clothes dryers, now have the FOUR wire hookup - so you have TWO (out of phase with each other) hots, a SAFETY ground for any 240 volt parts of the devise, and a NEUTRAL to RETURN current from one of the hot wires. This lets delicate electronics have a 120 volt source, and higher power (like the heater in the clothes dryer) still have its (zero current) SAFETY ground.
I searched online for a useful diagram of this; looked at about a dozen diagrams, and
NOT ONE of them mentioned that those two "hots" are NOT the same - hopefully the above explanation will help clear this up... Steve