Electricity Monitoring, Before The Meter {dkim-fail}

[ned+xtension at mrochek.com]

> I'm on the verge of installing a grid tied solar power system with
> battery and generator backup. My goal is to have continuous, reliable
> electrical service such that in an emergency I can continue to have a
> pressurized source of water to save my home from wildfire. I don't give
> a wit about the environment, and the system I'm building will cost far
> less than the cost to replace my home. I don't expect my current
> insurance company to renew my homeowners policy next year, and since
> I'd already been turned down by more than two dozen companies before I
> found them, I'm pretty sure I'll be self insuring after I'm dropped.

> My generator hookup now is a plug box wired into the 240 V buss bars of
> a subpanel, and I make sure to kick the main breaker at the meter off
> before I hook up the generator. Not at all to code, but it takes months
> to get a permit even for something as simple as a generator, and
> there's no way I'm losing another fridge full of food because of some
> bureaucratic SNAFU. Besides, the system I'm putting in will use
> inverters to manage how power is distributed, and there won't be a
> transfer switch, so there's no point spending upwards of $600 for the
> switch and another $500 for a permit just to replace it before the end
> of the year.


> Yes, it makes no sense to turn the power off when the wind blows, the
> humidity drops, and the moisture content of the vegetation around the
> power lines is extremely low. But for years, PG&E has been diverting
> money that should have been going into maintaining their equipment and
> keeping trees and brush clear from their power lines, using the money
> instead to prop up shareholder profits. They were taken to court and at
> that time I believe the sum was something like $4M, and that's just
> what they could prove. The Camp Fire was started when an insulator
> hanger on a steel tower that was over 100 years old broke, letting the
> bare high tension lead crash to the ground. It broke because it was
> worn, and because of the high winds that day. PG&E had been planning to
> replace those towers for years, they knew they were decrepit, but
> somehow never spent the money to do so. That's just one example of how
> far down hill the robustness of the grid equipment has gone. The most
> common failure are trees that blow over in the wind and land on power
> lines. Those trees should never have been allowed to grow that close to
> the lines to begin with, but somehow there's never been enough money in
> the budget to pay the crews that used to do that sort of thing. It's a
> man made emergency, one borne of management negligence and greed.

SCE is in a little better shape, but they were scared shitless by the
judgements against PG&E and so they are cutting power willy-nilly.

San Diego is the interesting case. Not only have they been doing a better job
on clearing brush to keep it from blowing/falling into the lines, they have
developed tech that can kill the power between the time the line breaks and it
hits the ground. And they have much better monitoring of their lines.

> Now back to my question. I'm not looking to tap into any hot leads. A
> current loop on the grid side of the main breaker would sense current
> flow, but I'm not an electrical engineer and don't know what to even
> look for to hack something up that would use one. I've seen ads for a
> red box that gets installed into a breaker box that uses such devices,
> but I don't remember the name of it, I don't know if it has an HA
> interface, and I don't know if it would work on the other side of the
> main breaker. Does this sound familiar to anyone?

If I were you I'd be looking at something like the Xantrex PowerHub 1800:

  http://www.xantrex.com/power-products/backup-power/xpower-powerhub-1800.aspx

My system is built around the Xantrex SW4048, but it's obsolete and requires a
separate charge controller and GTI unit to operate, which makes it pretty
pricey. (I originally had a Xantrex PC250 charge controller, but it blew out so
I replaced with a Morningstar MPPT.)

				Ned