Replies

1. 
   DanH | Jul 10, 2007 02:00pm | #1

   From the standpoint of measuring current, it shouldn't matter, but the meters measure watts, by simultaneously measuring current and voltage and effectively multiplying the two. The lack of a voltage on the second hot wire is the thing that could cause a problem -- should work in theory but hard to say in practice.

   Where you'll be installing, is the second leg of the 240V line available so it can be attached to the meter input? (Note that it won't do to attach the first hot to both legs.)

   So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
1. 
   ThePhiant | Jul 10, 2007 05:07pm | #4

   I'm not following your thinking.
   yes i could pull an additional wire to the input of the meter, but are you saying i can then get 110 from the output of the meter?

1. 
   DanH | Jul 10, 2007 05:52pm | #9

   Yeah, just don't connect anything to the load pin on one side. A standard residential meter should read accurately when 100% of the load is on one leg of the 240V line, and 0% on the other.
   So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin

1. 
   ThePhiant | Jul 11, 2007 01:44am | #11

   great idea!
   but does it really work?
   I hooked it up the way you said, and I understand the logic behind it but have you tried it out before? did anyone else?
   does it matter which side you connect to?

1. 
   DanH | Jul 11, 2007 02:18am | #13

   Yeah, it'll work. The accuracy will probably suffer a little bit, but should still be in spec. A residential meter should work correctly with all the load on one side, and, absent a load, the meter can't tell if there's a wire on the other load pin or not.
   So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin

2. 
   alwaysoverbudget | Jul 10, 2007 04:02pm | #2

   if this is a 12/2 110 ,less than 20 amp. harbor frieght sells a gauge that plugs in and you run through it. it will give you the usage. 20.00? larry

   hand me the chainsaw, i need to trim the casing just a hair.

1. 
   ThePhiant | Jul 10, 2007 05:08pm | #5

   it is a 20 amp, do they still work then?

1. 
   alwaysoverbudget | Jul 11, 2007 01:45am | #12

   i don't think 20 amps would be a problem.i just looked at the site and couldn't find them,but in the store the are right by the multie meters. larryhand me the chainsaw, i need to trim the casing just a hair.

3. 
   renosteinke | Jul 10, 2007 04:41pm | #3

   The meters likely need to have 240 present to operate properly.

   For the cost of the meters ... assuming they were purchased from a legitimate source ... their should have been instructions! Likewise, the manufacturers' web site likely has the information that you need.

   Forgive me if I seem a bit testy. I often do "service changes,' and one common feature is that the new service no longer has a separate meter for the water heater. As a result, I get all sorts of 'nod and a wink' requests to 'salvage' these 'extra' meters ... usually by parties that want to sneak a trailer onto their property ... zoning, codes, permits, neighbors be damned. Ditto for illegal apartment conversions.

   Such requests outrage me ... those meters cost a fair amount of money, and belong to the power company. "Salvaging" them is simple theft ... a detail that these folks know all too well. It's amazing ... when I suggest places to buy one, every such person turns out to know the prices and availability better than I! Yet, they never hesitate to ask me to join them in their criminal enterprise.

   Getting back to your request: assuming that the #12 is properly used, I'd be surprised if the monthly use exceeded $30.

   You might want to google "Kill-a-watt."

1. 
   ThePhiant | Jul 10, 2007 05:35pm | #7

   the meters were hand me downs and I have no history on them
   the kill a watt seems like a temp solution that
   living or camping on your own land should be a right and not a privilege! somebody living in a trailer is NOT a criminal enterprise, but an economic necessity! thanks for your compassion

1. 
   renosteinke | Jul 11, 2007 03:07am | #14

   I certainly understand your passion, and know nothing of your circumstances. I CAN say that I regularly encounter 'law-abiding' folks who seem to believe that following the law is something for OTHERS to do. Like it or not, there are lots of laws that limit your 'rights.' Specific to this discussion, many folks choose to move into an area - only to find their choice 'reversed' by a neighbor who flouts every CC&R, zoning ordinance and building code at will. Some even seem to consider it a 'game' to see just how far they can push. It's not a matter for chat room philosophizing; it's enough to know these rules exist in the real world, and can carry some pretty drastic penalties. For example, the news just yesterday reported an elderly woman being jailed for not watering her lawn! Maybe it doesn't carry the 'glamor' of robbing a bank ... but anything that carries a jail term meets my definition of crime. It is for these 'mini-sociopaths' I wrote my post. Yes, there are legitimate sources for such meters ... but I have yet to meet anybody that has one. I do see 'found' Utility Company meters at garage sales, in flea markets, etc. There's one word that describes these meters: stolen. Another complication, if you are going to try to sub-meter your service, is the matter of payment. It is almost certain that you will NOT have the right to simply turn them off at will. Utility and leasing laws vary greatly from place to place. As a 'separate residence,' it is very possible that the AHJ would want a minimum of 100 amp service to the residence. So much for that run of #12.... (That's also why there's something of a 'black market' for the old 60 amp meter pans!) Finally, look at this in economic terms. Such meters typically cost hundreds of dollars. To spend that kind on money, to measure a usage of even $40/ month ... that's a VERY long payback period. You might as well just build it into the rental rate.

1. 
   ThePhiant | Jul 11, 2007 06:35am | #18

   this meter I got was bought legit for $50 as it turns out, they do sell for that in the store

1. 
   renosteinke | Jul 12, 2007 02:53am | #19

   I am glad to see basic meters are now available, and affordable. The 1% accuracy claimed ought to be sufficient for most uses. I also note that meters certified to ANSI C12.1, and suitable for utility use, cost at least ten times as much. What's the difference? I have no idea ....

2. 
   DanH | Jul 12, 2007 03:37am | #20

   They're certified to remain accurate, probably to about 1/4%, for decades.
   So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin

2. 
   ThePhiant | Jul 12, 2007 08:14am | #21

   getting back to your comments about crime

   according to your definition, the woman that didn't water her lawn is a criminal!

   has it ever occured to you that what was law yesterday, is now considered offensive to oppose, e.g; a mixed marriage. there are legion examples of this.

   how do you feel about DanH supplying me with information about using a meter but not as intended by the Mfg. is he a criminal too?

   I have never met a man who hasn't broken a law. Have you?

2. 
   BilljustBill | Jul 11, 2007 03:12am | #15

   Reno,

   Along with the original poster's questions, I'd like to ask some related questions and 'pick your brain' for some insights about electric company's meters, please.

   How does one know if the electric meter is measuring/reading correctly? With no known power surges or lightening strikes, does an electric meter ever "Get too Old" to measure correctly?  Our local electric co-op will test them, but that's like getting the Fox to watch the Hen House....

   One day, I found they took out the mechanical digital meter that was installed in 1980, and installed a new meter a few months ago.  The new one has an LCD digital panel and I'm told that the reader now can be 500 ft. away and read the meter from his pickup.  How do I know if this one is actually correct?

   Thanks,

   Bill

    

    

1. 
   DanH | Jul 11, 2007 04:14am | #16

   In most states the utility is required to remove the meters and test them at some interval, tied to the reliability of the meter. And often, if the test shows the meter reading high, you're due a refund, according to the law.But these meters are remarkably reliable and accurate. Probably most could operate for 50 years without getting out of spec.The most common error (other than in reading the dials, which is self-correcting) is in setting up the meter. Though it's uncommon with residential meters, commercial meters may contain a shunt that "scales" the meter reading, and if the wrong shunt is installed, or the value of the shunt is improperly entered in the records, readings can be way off.There are special ammeters you can install in your breaker panel to continuously read your current, and by now I'd guess that some of these include computer logic to keep track of KWH. Don't know of any sources, though.
   So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin

2. 
   renosteinke | Jul 11, 2007 04:53am | #17

   I do not know the technical details of meter operation ... What I do know is that there has been a tremendous amount of engineering, and research, put into the meters. One of the design criteria has been, simply put, that most meter malfunctions will result in a low reading. From a theoretical angle, the meters measure 'watts,' and assume a sine wave.
   While 'watts' are often defined as 'volts x amps,' this is strictly true only for DC. With AC, time is a factor ... the voltage is always changing ... and some devices interact with that. That is why a 'watt' is not, strictly speaking, always the same as a 'volt-amp.' It is also why some devices appear to 'save' or reduce the power used by motors, transformers, an the like. Remote reading, or even remote control devices, are nothing new. How accurate are these meters? Well, one indication of their great accuracy (and reliability) is that power companies are increasingly using them to identify (and reduce) "line losses."
   Simply put, the power company makes a lot more power than they bill for. With computers and metering along various parts of the grid, they are increasingly able to identify problems. If they know your street is using $1000 worth of power, and they are only showing billings for $600 of it, they will start looking for the reason. That reason might be anything from bad cables ... to power theft.

4. 
   formula1 | Jul 10, 2007 05:32pm | #6

   The regular household type of meter with 5 wheels will operate properly whether it is measuring 120 or 240 volt power passing through; if you think about it, it has to - if everything in the house was shut off and only one 120V appliance was turned on, it would accurately measure that load usage.

   
   

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   Edited 7/10/2007 10:33 am ET by formula1

1. 
   ThePhiant | Jul 10, 2007 05:40pm | #8

   The regular household type of meter with 5 wheels will operate properly whether it is measuring 120 or 240 volt power passing through; if you think about it, it has to - if everything in the house was shut off and only one 120V appliance was turned on, it would accurately measure that load usage. I don't think you understand the question.
   both meters work when hooked up but they spin at different rates when I run a saw. which one is accurate?

1. 
   DanH | Jul 10, 2007 05:58pm | #10

   If the two meters do not register the same when properly connected to a given load, then at least one of them is broken.Note, however, that the aluminum disks may spin at different speeds -- the disk's rate of spin depends on the gearing in the meter. But if you connect the meters in series (output of one to the input of the other) and then to a load, the actual watt-hour readings (after some period of use) should be the same on both meters. And the readings should correspond roughly to the watt-hours you calculate for the load. (Eg, a 1000 watt space heater, run full blast for one hour, should rack up about 1 killowatt of usage.)
   So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin