I think they call that male to male extension cord setup a "suicide cord". It would blow the inverter in a spectacular manner, also. If you were extremely lucky the breaker might pop before killing the inverter. Not likely but possible.

Grid feeding is a tricky bit of electrickery best left to the experts.

Others may explain the "how" part.

Tom

The Truth is the Truth, even if no one believes it; and a lie is a lie even if everyone believes it

Now, if you are somewhere with no power, but your building is wired for regular electricity, you can use the suicide cord to energize the existing wiring. That works great for me on a remote cabin that I have down by the river.

But, the lines from the power company have been disconnected and removed for years and there is just a meter loop and pole there with no feeder lines from the power company so I am positive there will not be a connection to the grid unless something DRASTIC happens.

Grid tie inverters are made specifically for tieing in to the grid and have some special electrickery going on that looks for the presence of and seeks to synch-lock with it. REgular inverted (non-gridtie) don't have such electrickery, but they do have a lot of that expensive electric smoke! If you let it out, though it is very hard to find end expensive to replace. . .

I never understood how they could get so much of that electric smoke inside one of those tiny parts!

Have a great day!

The sensor detects the line voltage, frequency, and phase.

 - When it's within spec for an active power line the control computer shifts the inverter's frequency slightly, swinging the phase around until it's synchronized with the line frequency, in phase with the line, and at about the same voltage.  Then the controller fires the tie-in relay.  After that the inverter can feed the line by boosting its voltage slightly.

 - If something cuts the external power feed upstream of the neighborhood, motors and the like (and the inverter) will act as generators and keep the line "hot" for a while.  But the voltage and frequency will start to shift as the mechanical and other electrical loads pull the power from the rotary equipment faster than it's replaced by the inverter.  The sensor detects the phase and frequency drift, recognizes that the inverter is now feeding an "island", and opens the tie-in relay.  (The line-current sensor may also participate in this, detecting excessive load on the line side as another reason to cut off.)

Even if you could feed the line you don't want to:  The pole-pig transformer works just fine in reverse, so a lineman working to restore it could grab onto 15 kV where he expected a dead wire.

If the inverter isn't designed for grid-tie, it just free-runs.  There's nothing to swing it into sync with the line.  So it picks its own frequency and phase, mismatches the line, and tries VERY hard to drive enough current into the wires or pull enough current from them to swing the ENTIRE POWER GRID into sync with itself.  Of course it fails - pulling or driving enough current to boil the magic smoke out of the components.  And if you DO manage to get it running attached to a dead grid line it has nothing to avoid "islanding" and electrocuted linemen.

By the way:  Some companies (i.e. xantrex/outback) have models where the extra stuff is in an extra box, with the electronics hooking up to the main inverter's computer via a small signal bus (in addition to the heavy connections to the line and the inverter's AC side.)  This lets them sell grid-tie as an add-on upgrade.

 You can think of a grid tie system as two "parallel" sources of power. One being the grid with it's massive generators and transformers and feed lines. The other being your personal generation.

 In a proper and legal grid tie system, the two act in parallel, your system with a grid tie inverter will sense the frequency of the main grid and synchronize to it. In the event of a power failure in the grid, your system senses the shift in power and shuts off also, preventing any "backfeeding" into the grid which can be unsafe for a lineman coming in for repairs, thinking the grid power is dead. In the case of you generating more power than you are using the extra power will turn your meter in reverse thereby reducing your bill by the amount that you're overproducing.In some areas, a separate meter is required to record this energy that is "sold" back. This situation depends on your location, local codes and laws.

 During a power outage your system MUST (legally) be separated from the grid to prevent any accidental electrocutions, and it also protects your system from overloads. Imagine trying to power 50 households your size off off your inverter.

 There are, however grid tie inverters that do supply backup power via a battery bank, and these must be able to switch over to an isolated system in the case of a blackout.

 Wiring a non grid tie system to "parallel" with a grid tie system is not only dangerous but WILL let out the "magic smoke". First off the synchronization of the a/c cycles will be off, since a non-grid tie inverter has no way to match the frequency of the grid tied a/c.

 If you do choose to use both grid tie, and a separate non tied inverter and power system, it must be totally isolated! This means the hots, and the neutral and the ground(s). Other wise you are likely to burn up that precious equipment you just bought!

 Neutrals and ground wires are inter tied on some systems so not having them isolated totally will most likely cause problems in those areas.

 I have generalized somewhat in this post due to the fact that there are many different  A/C systems worldwide, and even from region to region. If you don't know all the details of your own power distribution system, this is an area best left to a qualified electrician, which in a lot of regions is required by law, anyway.

BEFORE YOU START:  Your house will have neutral bonded to ground.  DON'T use a cheap inverter which doesn't isolate the DC and AC sides (or you might find your battery terminals and inverter case with high voltage AC on them, or a "magic smoke release" if the inverter has a neutral-DC bond internally or you've grounded one side of your batteries.)  Use a motor-generator or an inverter that has been checked to be OK with neutral grounded.

FIRST:  Open the MAIN breaker.  This cuts you completely off the grid (though neutral will still be bonded to the grounding system at ONE point in the house.)
 - Put something through the "lock out" hole if available, or at least put a piece of masking tape over the breaker, as a reminder to unhook the genny or inverter before switching the breaker back on - and to show the lineman that you know what you're doing when he sees your lit-up house and comes by to tell you to shut down so he doesn't die while working on the line.

(If you have a subpanel with its own main breaker, and you're SURE your backfeed circuit is fed from it, you can turn off the main breaker on THAT.  Then you can use one of the other circuits from the main panel as an indicator of power restoration.)

SECOND:  Open all the individual breakers except those to the loads you want to keep powered and to the outlet you intend to backfeed.  (If the generator is a 120V model these will all have to be on one side - red or black - of the 240V feed, and no 240V loads.  If the generator is a 240V model be sure it feeds a 240V circuit with a neutral connection so you don't apply most of the 240V across the more lightly-loaded side of your house circuits.)

THIRD:  Open the genny's output breaker (or the breaker on the backfeed circuit - and make sure there's nothing on that circuit other than the genny.)  Plug in and fire up your genny, turning on the output breaker (or backfeed circuit's breaker) last.

NOTE:  Backfeeding a GFCI breaker or outlet will DESTROY it if it tries to open with backfeed power applied.  It will become an ORDINARY breaker with no GFCI function or an ordinary outlet.  So make sure your generator isn't sitting in a puddle and don't bump the "test" button while running it.  (Voice of experience:  I fried a $70 special-order 30A GFCI breaker for my travel trailer outlet by bumping the "test" button while backfeeding through it during a power outage.)

Shutting down after power restoration:

FIRST:  Shut off the genny or inverter.

SECOND:  Unplug the genny or inverter.  (Unplug BOTH ends of that suicide cord, house end first.)

Your "neutral" wire should be grounded in multiple places so I wouldn't be so worried about that.  I assume you have a grounding rod outside of your box, and perhaps also a tie into plumbing.  However, make sure your main breaker is OFF when "experimenting" inside the house.

I have heard that if you have a basic induction AC motor, and drive it (somewhat) over the rated speed, then it will generate power and self-synchronize with the grid.  

http://www.fieldlines.com/story/2006/6/7/223936/5604
http://www.gassavers.org/archive/index.php/Grid-Tie-and-Induction-Motors/t-5456.html

And, as I understand it, it stops generating when the grid power fails.  But, peronally, I don't think I'd want to mess with the grid without having approved grid-tie hardware.

If you want...

Search the internet for the term:  "Guerrilla Solar"

Also, in the past there was an inverter called:
"Trace Microsine Inverter" which was supposed to be grid capable 110V, 100W, but without all the other expensive stuff.  Look for models MS100/MS100U/ok4u

There is currently available the Enphase Micro Inverter.  I can't say it would be preferable to other systems...  but it is a modular grid-attached system, that in some senses is quite spectacular.  Each unit has a maximum of about 200W...  so one inverter certainly wouldn't run your whole house, but it might be worth looking at for grid-tied applications.
http://www.enphaseenergy.com/products/