Danny D'Amico writes:
Here is a picture of the incoming wires to my main circuit breaker:
http://farm3.staticflickr.com/2886/1...21cf1404_o.gif

If we follow those three wires *back* to the nearest transformer, what
do they look like (in terms of phase relationship to each other)?

Typical US residential distribution (many details omitted for simplification).


+------+
| |---------------- L1 (Line 1)
L1 ----| Pole | 120VAC
14KVAC | Pig |--------| 240VAC
L2 ----| | 120V |
N ----| |---------------- L2 (Line 2)
+------+ |
| |------- N (Ground_ED_ conductor)
|
gnd


Anywhere from 11,000 to 30,000 VAC, single-phase + transmission neutral,
enters the transformer which
has a primary winding and a secondary winding used to drop the
distribution voltage to the service voltage. The secondary winding
is 'center-tapped' and connected to GND. L1 and L2 are connected to the main breaker
in your service entrance panel. The N conductor from the pole pig is
connected to the grounded (neutral) bus-bar in the service entrance. The
grounding bus-bar in your service entrance is connected to a service ground
associated with the premises and that bus-bar is bonded to the grounded
bus-bar in your service entrance (and _only_ in your service entrance,
not downstream subpanels).

Note that the primary side of the pole pig is single phase for most
residential applications. The secondary side splits that single phase.