The dryer has a 240 volt plug for the washer as well if need be.
Here is a some pics of one example. Note that they are stacked but can also be side by side:
http://www.theartofdoingstuff.com/it-aint-that-hard-any-of-it-how-to-fix-your-dryer/
11.If the ground wire shown below from N to PE is not
part of the 3-wire cord assembly you have it must be
obtained/purchased separately and it must be
installed.
12.Install the last terminal block screw (Philips) and 1
grounding screw (T20 torx) at locations N and PE.
Hook it up like the instructions say for a 3 wire and leave the 'white' on the 'neutral' bar.
You are over thinking this. The instructions tell you what to do.
Use only a 4-wire/conductor power cord when
the appliance is installed in a mobile home,
recreational vehicle, in a new branch-circuit
installations or where the local codes do not
permit grounding through the neutral.
250.140 Frames of Ranges and Clothes Dryers. Frames
of electric ranges, wall-mounted ovens, counter-mounted
cooking units, clothes dryers, and outlet or junction boxes
that are part of the circuit for these appliances shall be
connected to the equipment grounding conductor in the
manner specified by 250.134 or 250.138.
Exception: For existing branch-circuit installations only
where an equipment grounding conductor is not present in
the outlet or junction box, the frames of electric ranges,
wall-mounted ovens, counter-mounted cooking units,
clothes dryers, and outlet or junction boxes that are part of
the circuit for these appliances shall be permitted to be
connected to the grounded circuit conductor if all the following
conditions are met.
(1) The supply circuit is 120/240-volt, single-phase, 3-wire;
or 208Y/120-volt derived from a 3-phase, 4-wire, wyeconnected
system.
(2) The grounded conductor is not smaller than 10 AWG
copper or 8 AWG aluminum.
(3) The grounded conductor is insulated, or the grounded
conductor is uninsulated and part of a Type SE serviceentrance
cable and the branch circuit originates at the
service equipment.
(4) Grounding contacts of receptacles furnished as part of
the equipment are bonded to the equipment.
Service Equipment. The necessary equipment, usually consisting
of a circuit breaker(s) or switch(es) and fuse(s) and
their accessories, connected to the load end of service conductors
to a building or other structure, or an otherwise designated
area, and intended to constitute the main control and cutoff of
the supply.