An amazing (to me) thing happened at our house yesterday. About mid morning, we started to notice several of our lights were out. Also, the stove had no power, but the fridge did. 3 of my GFCI circuits could not 'test' or reset at all indicative of no power.

Several circuits were fine others were out. It was really weird. We called the Edison and they said it sounded as if a phase was out.

I thought residential was single phase? Sure enough, they came out and hooked up a temporary voltage box of some sort and we were then able to get the heat back on. Today they are coming over to dig up my power line.

They asked if I had been digging recently in the yard. They noticed that I had installed a fence and asked me when it was installed. (Its been 18 mos).

Are there 3 phases to the house to give us the 240V for the stove, AC and other and then single phase from the panel to the services?

What might have caused this phase to drop out if not my digging? I did have utilities protection come out 18 months ago when I dug post holes for my fence. Could the damage have been done that long ago and just now showed up? Could anything else cause this short of someone damaging the underground line or a faulty wire? A tree root for example?

Any help would be appreciated. I feel like the Edison is setting me up for liability and I would like to be armed with some information. My understanding is they are responsible for the connection to the house no matter what unless they can prove I hit the line while digging, or didn't call utilities protection service.

Thanks