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How to read Utility Meters

    General Overview of Reading Utility Meters

    I was lucky. I knew how to read my meters when my normal water bill, averaging a 1000 gallons / month, suddenly showed I had used over 18,000 gallons. As I rushed to read the meter so I could gleefully correct the water company, I heard rushing water by the meter. Twenty years ago, my builder used the damned Blue Polybutylene pipe across my front yard, and now, after the deadline has past for any claims, my pipe was leaking. By the time I received the bill and began to take action, another 27,000 gallons was lost, a total of 45,000 gallons. No, the sound of water leaking near the meter (on MY side of the meter), could not be heard in the house.

    So, did my ability to read the meter save any water? You're damned right it did! Had I not known how to read the meter, I would have simply waited until the following day to call the water company, to complain about what seemed to be a clerical error, and then waited another few days for them to send someone out to check the meter. But because I found the problem that evening, I shut the water off and probably saved another 6,000 to 12,000 gallons. I was losing about 2,000+ gallons per day.

    No, my basement wasn't flooded and no neighbor's house floated off, so I guess I just contributed a lot of fresh, clean water to the local underground water table.

    That was an extreme example, but there are others reasons to know how to read the meters - on most utility meters there is a "spinner", something meant to indicate a small amount of usage. This spinner can indicate 1 ounce of water usage. One ounce!. And that is very useful determining if something is wasting water in your house!

    Keep one thing in mind, the exact usage indicated by the spinners vary from meter type to meter type. The usefulness of the spinner is not from knowing precisely how much it represents, but from knowing some energy or resource is being used and you have a very sensitive indicator to tell you that fact.

    So, let's read a water meter:

    How to Read a Water Meter

    Most utility meters vary from locale to locale and the water meter is no exception, but this one will do for an example.

    This meter is easy to read, it has only two dial values, one is the 'odometer'-style numbers along the bottom and the large red pointer to the outer dial.

    Water Meter

    The value of this meter is reading "0139,684 Gallons"

    You can easily see the 0139 numbers, then notice the 680 numbers have a black background. This is because your normal billing is in 1000's of gallons, although the meter indicates gallons and fractions of a gallon. The 0139 indicates 139 thousand gallons PLUS 680 gallons. Instead of having a hard-to-see decimal point (or comma), they change the colors of the numerals! But wait, the value was ...684 gallons, not 680. If you look very closely, that last digit on the right, the '0', is painted on and never changes. Where does the '0' - '9' gallons come from? From the large red dial - it indicates the actual gallon by gallon value - and it's pointing to '4'. That's how you get the 0139,684 gallons.

    If you look closely to the outer dial, there are division markers for tenths of gallons. 1/10th of a gallon is 128 / 10 or 12.8 ounces. But I said you could see a single ounce of usage. See the red triangle on the left near the 7 and 8? That's the spinner and it rotates three times for every 1/10 gallon used on the big dial. 12.8 / 3 is 4.26 ounces for each complete rotation of the red spinner. Therefore, from each tip of the triangle to the next is 1/3 rotation or 1/3 of 4.26 ounces or about 1.4 ounces! By carefully watching the spinner, you can see the water usage from a dripping faucet or a toilet tank with a quiet, slow leak.

    Your spinner may have a different ratio, but you can determine your values by turning a faucet on very slightly and counting the spinner revolutions for every increment on the large dial. And then do like the professionals, turn off all the water usage inside the house and verify your spinner doesn't move!

    Some water meters read CUBIC FEET of water used, rather than GALLONS. Actually they read in ccf. (or HUNDREDS of cubic feet of water). To make the numbers useful to you, each ccf is 748 gallons.

    How to Read an Electric Meter

    The electric meter is definitely more difficult to read than the water meter. First, there are more dials, and notice every other dial is reversed like a backwards clock face. The reason for the reversals is the mechanical convenience of the gears that turn the dials - it's a more reliable design with less parts to fail.

    When reading multiple dials, the primary rule is how to handle to a dial that points almost directly to a number. Take the leftmost dial, you can see it doesn't quite point to 0, so its value is still 9. But imagine if it were closer to the 0, how could you tell if it was still 9 or had moved to the next number, 0?

    When a dial is very close to a number, look at the next dial down. In this case, the one just to the right. Is it somewhere between 0 and 2, or between 8 and 0? For that first dial to point directly to a number, the next dial over must be near 0, either just before or just after 0. THAT second dial's position settles the question about the first dial. You may need to think about this concept and re-read this paragraph. It is very necessary to correctly read your meter.

    Electric Meter

    Now let's read this meter. The first dial is '9', although it's close to '0', the next dial down is between 7 and 8 so this first digit will become '0' only later, after that second dial finally passes '0'. The second digit is '7' (beyond 7, but definitely not 8 yet). The third digit is '5', the next is '6', then the last is '3'. The current reading is "97563 Kilowatt/Hours".

    Notice the final meter reading is in Kilowatt Hours (or 1000 watt hours) - still in thousands, just like the water meter.

    Most of the time, the average house has a number of electrical devices drawing power, such as refrigerators and clocks. And you can see the power usage of them with the spinner - located immediately under words "KILOWATT HOURS" there is a slot across the meter, and the edge of a thin, flat disc is visible. It is marked numerically 0 to 100 by 10s and with 100 small tick marks. On this meter, each full revolution of the disc is 7.2 watts. ( Why exactly 7.2? ) With the disc is making a full revolution every 30 seconds, or 120 revs per hour, then 120 X 7.2 = 864 Watts at that moment. If that pace continues for an hour, then 864 watt/hours is consumed, which is 0.864 KWH.

    Notice if the disc makes one revolution for 7.2 watts, then each small mark around the disc represents 0.072 watts or 72 milliwatts. This extreme sensitivity allows electricians to check for faults and to verify if ANYTHING is drawing power at that time.

    All homes have breaker or fuse boxes inside that can be used to turn off the power to the home. Some apartments and condos have external power switches near the power meters. If your power is off and you want the power turned on, you must either turn off your main breaker for the entire house or be at home when the service person arrives. For when you have the power restored, the person installing the meter will immediately notice the spinner moving. If you are not home, they will have no way of knowing whether that current is running only your refrigerator or perhaps a stovetop burner! For safety they cannot leave your power connected. If there is an outside switch, they can turn that switch off, and leave a note on your door, and you'll have to turn the switch on. But for a house, if you're not home, you'll have to make another appointment and be home the next time, or leave your main breakers turned off.

    No, you don't have to turn your power completely off just to get the service transferred to your name - this is only in the case where there was NO power at the time, and it needed to be restored. All utilities prefer to have you just transfer the account from one person's name to the next and save the actual visit from a utility worker.

    Don't read this! This is painfully detailed information about how this meter's spinner ended up with such a round number like 7.2 watts per revolution.

    On the face of the meter, you can see "Rr 13 8/9", which is the worm gear ratio from the shaft of the spinner disc to the idler gear. "Rs" is standard at 100 for most GE meters and that's the ratio from the idler gear to one revolution of the least significant digit on the meter. "Rg" is the total gear ratio (Rg = Rr X Rs), so Rg = 13.88 X 100 = 1388. And one revolution of the least significant digit is 10,000 KW (one complete REVOLUTION of the dial, not just one number).
    This 10,000 KW is divided down 1388 times driving the spinner disc. So 10,000 KW divided down 1388 times (10,000 / 1388 = 7.2), or 7.2 watts per revolution of the disc. And with 100 divisions on the disc, you get a resolution of 72 mw. per division.

    Oh, there's also a simpler way to figure this. "Kh" is the watthour constant, a.k.a., the watts/revolution of the disc. AND, if you look in the lower right side of the meter face, you'll see "Kh 7.2". Yes, you could have looked there, but wasn't my explanation above more fun to follow?

    How to Read a Natural Gas Meter

    The gas meter is similar to the electric meter, with multiple dials, every other one is reversed, and indicates in 'hundreds' of units.

    Describing how to read the electric meter detailed how the dials affect each other when a dial points directly to a number - is it above or below that number? This gas meter is a textbook example of a confusing meter - meaning all four dials point directly to a number and almost all of them require you to check the next dial over to determine each dial's value.

    Here the first dial on the left is around '1', but is it really 1 or still a 0? Remember the rule we learned above? We look at the next dial down and we find the second dial is 'less than 0', not past 0, so the first digit is still 0. The second dial is about 9, but the third dial is 'below 0' and that tells us the second dial is still 8. The third dial is around 8 and looking at the fourth dial tells us the third is really 8 because that fourth dial shows 2 (and has gone past 0).

    Gas Meter

    The current meter reading is "0882 Hundred Cubic Feet (CCF)". How did we know it was in 'hundreds'? Look at the numbers above each dial. The last one on the right says '1000'. But look CLOSER and you'll see 'per rev' under that dial, meaning 1000 Cubic Feet PER FULL REVOLUTION. And if a full revolution is 1000 Cubic Feet, then each small increment with a number is 100 cubic feet. This detail is VERY important.

    These are all the numbers needed to 'read' this meter, they are in hundreds of cubic feet, which is the billing unit from the gas company and almost equal a therm.

    Yes, there are 'safety' spinners on this meter also, but they don't spin as fast as the spinners on the electric and water meters. See the two dials on the lower left of the meter? The right dial is labeled "One Foot", making one full revolution for every cubic foot of gas used. The leftmost lower dial is labeled "Quarter Foot", making one full revolution for every 1/4 cubic foot of gas used. A typical gas furnace pilot light uses about 1000 BTU, which is about 1 cubic foot of gas. You might think you could see the two dials spin, but that would be incorrect. Yes, that's 1000 BTU per hour and 1 cubic foot of gas per hour, so you get one revolution of the "One Foot" dial per hour, and one revolution of the "Quarter Foot" dial every 15 minutes - so wait 4 minutes and you can see the Quarter dial move 1/4 a revolution. Not exactly spinning, but within a minute, you could definitely see the Quarter dial move enough to know something was releasing gas. Pilot lights on range tops use about 1/4 to 1/3 the gas the furnace pilot uses.

    Yet, if your 40,000 BTU gas water heater fires up, you'll see the Quarter dial make one revolution about every 25 seconds. Or, your 80,000 BTU furnace makes the Quarter dial revolve once every 12 seconds or so, still maybe not 'spinning', but noticeably moving!

    Every revolution of the left spinner indicates 1/4 cubic foot of gas, and the right spinner makes 1/4 revolution. But that right spinner must make 100 revolutions to increase the LEAST DIGIT of the 'meter reading'. That is, to change the reading of 0882 to 0883, the right spinner must turn 100 times.

    The spinners can be used to accurately measure current usage - although you might have to sit and stare, while timing them and waiting for a significant change. They cannot be used for cummulative usage, say, measuring a furnace over a period of a day or so. The spinners will rotate many times, but the actual numeric counters are not likely to move more than even one digit. And with no 'intermediate' dials to document exactly how many times the spinner rotated, you'll have NO accuracy until the numeric dials begin to increment.

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    Copyright © 2003- Tom Scogin    Norcross, GA.    All rights reserved.