What REC said: was "lost electricity"

"The Turtle only transmits the information that the mechanical functions of the meter are recording. In the rare cases where a Turtle doesn?t report data in time for a monthly billing, an estimated ========= reading will be used until the problem can be fixed. Where discrepancies exist, the mechanical numbers on the meter can be used to determine actual usage."

To add to what has been said, I would still be concerned about the mysterious days when power spiked. There is a 90% chance that it is explainable, but I'll relate what happened when we first moved into our 1960s house in Florida.

The house had a 150 amp entrance. I didn't give a second thought about that, since it had obviously worked for over twenty years. It also had an seven year old heat pump, a pool pump, a sprinkler pump, lots of incandescent and halogen lighting, an electric dryer, dishwasher, and some other lesser loads.

During the first summer, I noticed that our electric bill was a lot. I had no way of being sure why this was the case, so I began poking around. When I went outside near the meter, I could smell something hot, like hot electric wire insulation. I then felt the breakers, which felt a little warm but fine, then moved on to the meter, and discovered that the conduit leading from the meter box to the breakers was too hot to touch.

I called in an electrician, and he was able to open things up. The aluminum wire between the meter and the breaker box had been heated to a point that it had begun to seriously corrode and add resistance of its own, and had _almost_ burned away enough insulation between the wires to create a direct short.

What had happened? The age and type of the wiring was, of course, a factor, but the issue we had not considered was that during the summer we might run all of the major power users at the same time. The pool needed cleaning, it was hot in the house, the lawn was getting dry, and because we were sweating and drinking lots of water, the laundry and dishes were being done, all during the late afternoon. The _cumulative_ draw was enough to damage the connection to the aluminum wire and the added resistance was overheating both the connection and wire.

Had I not been sniffing around, we would have had an electrical fire at a spot where it would be impossible to shut off the current without either the fire or power department breaking into the transformer box, and we likely would have had severe damage to the house.

Once the wire was replaced and connections repaired, our power usage went down by a significant amount.

The moral of the story? Don't let those high power usage days go unchallenged.

snip

Thanks for the thoughts. I don't plan to but now that it's gone, it will be hard to track down. I'll keep my nose to the ground.

Steve southiowa

I can suggest two other possible causes for the high readings. There could have been something going on with the meter so it was somehow doubling the numbers or someone else was stealing power.

If someone had run an extension cord or otherwise tapped into his power then they might have disconnected when they realized the power company would be around inspecting everything.

Anthony

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Right answer, wrong question, or at least situation... :)

In the above instance it was as if another resistive load were introduced into the line--think adding your electric dryer's heating element (or more nearly the stove eye) -- that wouldn't add usage? That heat has to come from somewhere. :)

Sure. Ask him why they fill the transformer with oil and circulate it then.

Aluminum conductors evaporate because their resistance increases exponentially, Copper is not as bad.

he claims a overheated line will not majorily change power consumption. very minor if any difference

Not to pick on your buddy, because this is obviously one of those "idiot in the middle" problems, but... Guess again.

If a length of conduit is "too hot to touch" as the OP described it then it is radiating significant power.

Let's do a little math to find out how much. We'll be using Stefan-boltzmann to compute radiated power from a length of conduit. Let's say that there is 6 ft of 2" conduit with a thermal emissivity of 0.85. A temperature too hot to touch might be

There's a slick little Stefan-boltzmann calculator here:

Plugging that into the SB model we get 115 watts. If it radiates constantly for the whole month, that's 7*24*30.25 = 546 hours. Times 115 watts is 63kWh. At 10 cents a kWh, that works out to $6.30.

If ambient were freezing, 0 deg C and the conduit were 80 deg then the pipe radiates

If the conduit is weathered and dirty then the emissivity might be closer to

If that length of outside conduit is radiating power then so is the inside conduit, the breaker terminals, the meter terminals and the conduit containing the drop from the weatherhead. We can confidently say that the whole mess would use $10/month.

If his usual bill around $100/month then a 10% change in either direction would certainly be noticed.

John

-- John De Armond See my website for my current email address

He's not talking resistance -- he's talking about a short circuit. Please be sure of your terms before you call someone else names, and insult them.

I've known of houses with broken down insulation in the lead in wire, creating a high energy bill. So, it's a real condition.

Transformers are filled with oil for aluminum, or copper, conductors to transfer heat to the case, then to the air. High current through conductors creates a lot of I squared R heat. With conductors tightly packed together in a transformer winding the heat is difficult to dissipate.

Last I heard, at reasonable temperatures the resistance of aluminum, like that of copper, doesn't significantly change.

Kindly provide a link with information on aluminum conductors evaporating.

I agree with dpb's answer to hallerb - wrong question.

Or someone in the house was using a portable heater.

I don't think so.

"I called in an electrician, and he was able to open things up. The >aluminum wire between the meter and the breaker box had been heated to >a point that it had begun to seriously corrode and add resistance of >its own, and had _almost_ burned away enough insulation between the >wires to create a direct short."

Please be

More total bullshit. That would burn the house down long before you got the bill. As Mike said, if the connection where so hot it was shining brightly in the daylight... and indeed that is what it would take to create a high energy bill, and it *would* set fire to something.

Bob F wrote: ...

Proportionately longer time at lower voltage is still same power...

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Really? Then according to your expert theory, my restaurant ought to have burned down long ago.

That conduit has been too hot to touch on occasion. I monitored it closely in the summer time. I'd have loved to have replaced it but the city says that I can't do my own electrical work and I'm not about to pay someone else to do it so... It's been there since the 40s and it'll probably be there until the building is torn down.

Perhaps you ought to look at the other post I made in this thread about how to compute irradiative losses from a hot object. The concept is simple enough for someone even of your caliber to understand.

Maybe you ought to get your code book out too. At various places it discusses the losses involved in various wire and cable temperature rises.

John

-- John De Armond See my website for my current email address

Sure sonny. Now tell us just how much electricity that mess actually used. Nothing there used up enough power to cost more than 20 cents a month!

But not so simple that you quite understand it, eh?

Another item you don't seem to quite understand yet.

My, such charm and wit.

OK, well "Pop", let's go back to that Stefan-Boltzmann calculator and do a little math.

The conduit between the meter base and that box is about 40 ft of 2" rigid conduit. It runs exposed so we don't need to worry about conduction losses, only radiative and convective.

Forty feet of 2" conduit is 21 sq ft. Let's use 80 deg C for the conduit because that is just about "too hot to touch" and 20 deg ambient. We'll use 0.95 emissivity since the conduit is old and dirty and pretty close to a black body. That comes out to 858 watts. In that temperature range, convective losses will be about twice those of radiative losses so we'll figure 1716 watts there for a total of 2,574 watts.

My restaurant was open about 70 hours a week and the load remained fairly constant throughout the day so 2,574watts * 70hours * 4weeks = 721kWh. At $0.09 per kWh, that's $64.89 per month. A bit more than 20 cents a month, wouldn't you say? Chop the calculated amount in half or even by 10 if you like. Doesn't matter, you're still wrong by an order of magnitude.

And I didn't even try to account for the cost of air conditioning that heat to the outside, a necessary task since all but a couple of feet of the conduit runs in air conditioned spaces.

Sanity check: Using the 0.000292 ohms per foot from

Feel free to plug your own numbers and see what you get. It'll be > 20 cents.

You remind me of that old saying: "Those who ignore the math are doomed to look like idiots."

John

-- John De Armond See my website for my current email address

Except for the losses where the problem is. Which don't heat the house if they're outside. Sorry.

I guess you can't get a high bill from a 3000 watt heater locked on

After all a 3000 watt heater doesn't glow so it can't produce the

I guess he meant a $5000 electric bill before you can have a fire.

The one time I saw this, the electrician pulled the lead in wire, that had been from the meter to the panel box. He set the wire on the ground, and used his Simpson VOM to read from hot to hot -- there was less than infinity resistance. I didn't see on his meter how many tens or hundreds of K-ohms, but there would have been current flow, with 220 VAC applied.