Home Power Monitoring Hack

dvogt writes "You think your power bill is bad? I built a power monitoring system to monitor every circuit in my house with three second resolution for over a year. And while I had to rewire all my electrical to do it, I can now reconcile my electricity bill down to the penny... Of course when my wife figured out most of the bill was because of my computer gear I had to build her a dome, so reader beware!" From the article: "About a year ago I developed a web based power monitoring application for data centers. The application was designed to monitor thousands of individual branch circuits using current transducers at the breaker panels. Among other things, the data logging requirements were to provide one year of min/max/mean measurement data with one minute resolution per circuit. Since I had all the hardware for testing, I figured what better way to test things than to install it in my own home."

Comments

Does your home still meet safety codes?

[CyricZ]

"while I had to rewire all my electrical to do it"

Most areas have municipal safety codes when it comes to stuff such as wiring. Are you sure your wiring is compliant with such standards? Has it been approved by your local building inspector?

Re:Does your home still meet safety codes?

[CyricZ]

Just because it is working now does not mean that it will be in several weeks, months or years. Such codes are in place to prevent home hackery like this, especially in the case of electrical wiring. The potential for his modifications to fail are astronomical. And if he did such modifications without proper inspections, then the situation could get very hairy were things to go wrong.

Perhaps his insurance company would not pay him if it was found that his uninspected electrical modifications were the cause of his house burning down, for instance.

Re:Does your home still meet safety codes?

[ErikZ]

Such codes are in place to prevent home hackery like this, especially in the case of electrical wiring. The potential for his modifications to fail are astronomical.

I agree! Think of the dangers of brewing your own beer, working on your car, or even programming! Almost all viruses were programmed without any kind of government oversight.

There should be codes that are enforced by the governemnt that touch upon everything you can possibly do. To protect you, and others, from yourself.

Seriously, the codes are there to protect people from substandard wiring. But to insist that you have no right to modify the wiring in your own house is too "Big Brother" for me.

Re:Does your home still meet safety codes?

[cyb97]

getting off topic here, but what happens to your "modifications" when you sell your house?

Caveat emperor?

Re:Does your home still meet safety codes?

[kent_eh]

From TFA:

The current transducers are actually really small and they clip on to the wiring

The power monitoring system is not connected dsirectly to the wiring. It is using inductive sampling.

I serioisly doubt that having an inductive device near the conductor (outside the insulation) has any impact on the overall safety of his house's wiring.

Re:Does your home still meet safety codes?

[CyricZ]

Remind me never to move to Tennessee (not that I ever would, mind you). I'd much rather live in a city or township where inspections of homeowner (ie. non-professional) renovations, especially to potentially hazardous systems like the electrical system, are mandatory. I don't trust redneck cowboys to properly wire anything safely, let alone a house. It isn't a matter of "freedom" to get your wiring inspected; it's a matter of common sense dictating that any avoidable disaster should be avoided.

Re:Does your home still meet safety codes?

[anthony_dipierro]

A second set of eyes never hurts.

Even if that were true, something not hurting and something being legally mandated are two very different things.

Have to say

[zegebbers]

Since I had all the hardware for testing, I figured what better way to test things than to install it in my own home.

That's an awesome attitude that we don't get enough of on slashdot these days :(

Very cool, but a potentially dangerous area

[Sv-Manowar]

The screenshots of the monitoring software in use and everything make this seem extremely cool, but the potential risks seem huge. Obviously from the article this guy has done this kind of thing for work and had all the right equipment. I'd hate to see the results of someone lacking these vital elements 'hacking' their mains power system to get pretty graphs. The website says as much in its disclaimers too.

Re:Another way to do it: read the meter

[d2_m_viant]

Yes, but that won't do much if the power company is cheating you. The article's way, you'd be more able to catch the power company charging you for something you didn't use.

On a side note: Imagine trying to convince the customer service rep on the phone that you rewired your house with a homemade power monitoring system and your monthly audits of your electrical usage uncovered the error...me thinks you'd have better luck convincing a Slashdot reader to install the WeatherBug...

I would love to see screenshots of the effect.

[CyricZ]

I would love to see screenshots from the program he is using showing the power consumption of his web servers during this slashdotting. Indeed, it would be beneficial to know more about his hardware setup, too. It would be very interesting to correlate the number of hits/minute with the minute-by-minute power usage of his server(s).

Re:SAD TWAT

[joelsanda]

So assuming he did it to try and save money, after all what is any other point of doing it...

Maybe he did because he was interested in doing it? Which would make him a fairly clever bastard; because I'm sure there are more people who would criticize's another interest than actually do the work (the interesting part?) themselves.

Holy crap!

[pr0nbot]

Surely the next news item has to be "slashdot editor reads TFA"!

Re:From my knowledge....

[Anonymous Coward]

1. Is is magical, no it creates a samll load on the circuit

   It creates a very small additional inductance in the line. Putting your DVM onto a circuit creates a very small additional conductance in the circuit. Both have very small effects if you are using them appropriately; you cannot insert a sensor and have zero effect.

2. this can change the pwoer factor

   I'm certain that it does. I'm also certain that you'd need sensitive equipment to measure the difference.

3. the motor could be an induction motor

   COULD be? Certainly is, and it's a capacitor-start unit to boot. Might not have a running capacitor, but I'm not up on what's in dryers these days - I suspect it did (see below).

4. a change in power factor could change the efficiency of the motor causing it (or the wiring) to heat up more than usual.

   Two things wrong with that hypothesis:

   • If the sensor caused the motor to overheat, it was way too close to its ratings anyway.
   • An overheating motor is inconsistent with the failure, which would have shown a very slow change due to increasing winding resistance until the thermal cutout opened. The failure of the motor showed marked abnormalities in power consumption until final failure, more consistent with progressive breakdown of a run capacitor.

If you have any speculations based on the available evidence, go ahead and post - I personally think you're just another bloviator.