# 120V from both legs

I was wondering if there is a simple, correct, and safe way to draw 120V equally from both legs of US standard two leg household service. What I
want to do is reduce my electricity bill by eliminating uneven draw from each leg. US meters run as if the maximum draw from either leg is being pulled from both legs. When your refrigerator compressor runs, you pay for the same amount of current being pulled from the other leg as well.
Most electricians will say that by putting an even number of 120V breakers on each leg will balance your draw on both legs, but I think that is a crock. Draw on either leg will almost never be balanced with this method. What do I do, wait for the refrigerator compressor to turn on one leg so I can run my shop vac on the other leg?
I thought that if I could change the phase of one leg 180 degrees, I could connect it in parallel with the other leg.
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WRONG! You have been fed a pack of lies and have believed them. You can draw all of the current from one leg, half from each, or any other combination and the meter will measure the correct usage. Anyone with any metering knowledge at all knows this and anyone with the simplest meter test equipment can prove it.
The way to lower your bill is to use less electricity.
Charles Perry P.E. who is never amazed at the outrageous utility meter stories he hears, but is always amazed that people believe them
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OK. I guess I'll do some experimenting. I know that I sould take everything with a grain of salt, but the source that's telling me it's bunk (usenet) is the same place that I read this (mis)information in the first place.
The truth is out there, but where?

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"Handbook for Electricity Metering", Edison Electric Institute, 1992 (although there is a newer version now). It is the bible for electric metering.
Also, for about \$1000 a day, I will be more than happy to test your theory. I always warn customers ahead of time when it is obvious that the testing will not get the answer they want, but if they insist, I take the money and do the testing.
Charles Perry P.E.
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Sounds like this may be an urban legend created as a perversion of the following reasoning: http://groups.google.com/groups?q=g:thl3419501793d&dq=&hl=en&lr=&ie=UTF-8&selm43729%40news.IPSWITCH.COMM google thread thl3419501793d

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Could be (I didn't actually read Dan Lanciani's spiel in your link - though if it makes you more comfortable you can consider that Dan Lanciani acknowledges having little knowledge while Mr. Perry and others here are very much knowledgeable). I'll second the debunking. The meter knows how much energy you are using and you get billed accordingly. Certainly as far as unbalanced load is concerned anyways. A simple way to verify it is to just call the utility. I'm sure they'll happily tell you on the phone that it works that way, and they may be able provide some document, or website, to that effect. I am assuming you would be content that the utility would not outright lie to you on the matter.
j
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though
far
that
By the way, unless you have some reason to believe otherwise, your home probably has reasonably balanced load. Utilities like for loads to be reasonably well balanced so that their lines, transformers, generators, etc. can carry maximal loads and provide balanced voltages. If your loads were not all that well balanced you probably wouldn't have much to worry about.
j
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how
to
website,
would
etc.
P.P.S. "Top-posting" is generally frowned upon, FYI.
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The effects of one house with an unbalanced load on a utility system stop at the first distribution transformer that serves that house, it is not passed along to the rest of the system.
The utility itself may have an unbalance problem with the load or number of houses on each of the 3 three legs of a three phase feeder but that is the problem of the utility (not customer caused).
BTW, 20 or 30 years ago I recall hardware stores selling "light-bulb savers". These were nothing more than small diodes that you would insert in the light socket (incandescent, versus compact fluourescent being the standard at the time), and then screw the bulb in over the saver. The claim was that the bulb would last a lifetime and energy would be saved.
Well, it was true, the bulbs, did last longer, but the lights only burned at half brightness because they received half-wave rectification of the current.
This discussion of accurate meters with no neutral got me to thinking. Would a standard meter accurately measure the power consumed by one of these things (because of the pulsating DC component)?
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There is no reason to look at the neutral. If x current is flowing in phase A and y current is flowing in phase B they simply add x+y to get the load. Think of it as a 120v equivilent. If x is significantly different than y the difference is coming back on the neutral so you only get charged once. The part that is coming back on y represents a 240v load and you get charged twice for that. It may be an oversimplification but the model works.
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Short answer?? YES. The modern kwh meter (either electromechanical or electronic) is just so d___ good at doing what it is designed for you'd be amazed. High harmonics (non-linear loads), half-wave, displacement power factor, unbalanced legs, voltage variations, you name it, it still comes out right.
daestrom
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perversion of the

Lanciani
others here are

meter knows how

Certainly as far

verify it is to

the phone that

document, or website,

utility would

I tend to agree...however Ive had them lie to me regarding demand charge and power factor adjustments at industrial facilities nation wide, repeatedly...many dont even have a clue what those factors are... the companies in some cases have even changed the terms on the billing statement to occlude demand charges.
You can save an industrial firm a lot of money in many cases by getting rid of a bad harmonics situation (current wasted to the neutral and between lines due to wave distortions etc...back emf from motors and transformers...and such as large scale transormer stage lighting). I dont do a lot of this. when I do I spend \$500 and rent a set up that clamps to all 3 lines for amperage, reads voltage and the neutral... and computes the power factor issues hour to hour over the duration of the test.. I've seen some horrendous losses due to these factors...some back fed distortions from other nearby facilities. Desk top computer power supplies can backfeed serious distortion into a buildings power grid. Not single home though..but a problem in a large building.
I had been entirely unware of the problem until a client raised the issue and I studied up... it can get complex. But there are books on the situation and instrument rental outfits that specialize in the test eq (25k for a real good set up)...rental is much less.
Phil Scott

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<snip>
Back emf from motors causing harmonics?

You do realize that harmonics have a negligable effect on kWh, and no affect on displacement power factor? I really don't know of an industrial metering setup that penalizes for harmonics. Perhaps you could point one out.
Charles Perry P.E.
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regarding
cases
wasted to

Oh yes... like a barber shop quartet. Searching googles web tab I got 45,000 hits on the following key word string. 'Electric, harmonics, motors, line' You could trim the list down by adding in EMF, phase distortion, and power factor.
This one was typical..it includes a section deeper in the body of text that addresses these issues.

clamps to

and
due to

nearby
single
But
outfits
kWh, and no affect

No I don't. I have actually an entirely oposite view. But no use in hassling each other, there is plenty written on these issues..its not something new at all, with industrial applications at least... it might be new to the residential sector though.
I will decline to comment further in the interests of peace and harmony and recommend that anyone interested in these issues has available to them limitless information on the internet by searching Googles 'web' tab with the key word string mentioned above.
www.google.com hit the 'web' tab on the top left of the box... then type in yer key words.

one out.
There is not such an animal to my knowledge, nor should there be... but the power factor is calculated and the bill based on that. Power factor deviations stem from harmonic disturbances (and a few other things). Utility companies have a concern with EMF impedance, and the repercussions beyond a facility getting to the larger grid, and will address that with owners in number of ways... power factor correction capacitors included...and those costs are passed on to the customer.
To address one of your earlier remarks.. I dont know if this is suitable but it is quite common to install power factor correction capacitors on industrial motors, boosting the net motor efficiency and reducing utility costs, not just the cost of running the motor but also providing a better pf to the rest of the equipment in the facility.
These issues are not commonly known but the information is available as mentioned above.
Phil Scott

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<snip>
That link does not support your claims. Motors create very low levels of harmonics. Filtering these harmonics is NOT generally worth the cost in energy savings. Correcting power factor (displacement power factor) with capacitors is a good idea since it reduces the magnitude of the current flowing to the motor, reducing losses in the entire system. <snip>

Harmonics have no effect on displacement power factor. Period. Quite simple actually. Displacement power factor is defined as the phase angle between the voltage and current at the fundamental frequency. By definition, harmonics are not even included.
<snip>

Displacement power factor excludes harmonics. Poor displacement power factor is caused by inductive, or capacitive, loads. Yes, I have seen facilities with leading power factors. It is just as troubling as lagging, sometimes even worse.

?????
True, utilities are concerned with the power factor of large customers, the displacement power factor. This is corrected using capacitors. Harmonic filtering is sometimes required in such installations, but not for the reasons you state. It is done to avoid resonances that can damage the capacitor bank or other equipment.

They are quite commonly known in the power quality and power metering fields.
BTW, you might be surprised to find the source of much of the information in the link you provided ;-)
Charles Perry P.E.
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following
the
low levels of

worth the cost in

factor) with

the current

on
But
industrial
residential
Period. Quite simple

angle between

definition,
point
there
based on

displacement power

have seen

troubling as lagging,

correction
customers, the

capacitors. Harmonic

not for the

damage the

this
net
cost
metering
the information in

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----------- I have problems with the above statements. There appears to be almost a mantra in place "pf correction is good for all evils" It isn't and whether it is justified or not depends on the situation-both technical and economic analysis is needed to determine whether it is needed and, if so, how much (correction to unity pf is generally not economic or necessary).
. Adding power factor correction capacitors on industrial motors does < not

<may> increase efficiency slightly as typically efficiency is best at 100-105% of rated voltage. Of course, if the voltage is a bit higher than normal - pf of the motor drops which has a counter effect. It also does <not> provide a better pf to other apparatus (to say so is meaningless ). Motors and other apparatus have their own pf depending on their loads -they suck or blow vars as well as watts- provide 400V 3 phase to a motor and it really doesn't know or care that there is a capacitor bank hung across its terminals. It "sees" 400V 3 phase and it sees a load- the power factor of the motor follows from that (overall pf is increased by the pf but the motor behaviour is not modified). If the pf correction makes it "see" some other voltage then there is modification of motor behaviour which may be good, bad or indifferent. All power factor correction does is provide "upstream" benefits by providing some or all of the reactive needs from a local source rather than the utility. A side benefit is better voltages at heavy load (and possible overvoltages at light load). In some cases power factor capacitors attached to and switched with the motors can lead to serious problems- particularly where a transfer is made from the utility to a backup system.
--
Don Kelly
snipped-for-privacy@peeshaw.ca
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following
the
low levels of

worth the cost in

factor) with

the current

on
But
industrial
residential
Period. Quite simple

angle between

definition,
I think you might wish to read a little more on the issue.

point
there
based on

displacement power

have seen

troubling as lagging,

To clarify... another term is used commonly 'back EMF' thats a out of phase current that 'travels' back up the feeders to the larger local grid and in many cases to the local area utility grid. From what I can see of your responses so far you are quite bright but just on well read on this narrow spectrum of issues.

correction
customers, the

capacitors. Harmonic

not for the

damage the

You are quite knowledgeable..but in my view short on a narrow range of issues in this area.

this
net
cost
metering
correct
the information in

I just scanned the first few links and posted that one as typical... there were 45,000 other hits. My information comes from my experience consulting industrial facilities etc.
I would agree with you that one source seldom has entirely complete and comprehensive data. One should do thier own research. I always have this problem when I post a single link..there are always some nit or other to pick.. so I post the search string also.
Phil Scott

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<snip
I think you may need to get a copy of IEEE std 100. I will give you a little clue, there is more than one kind of power factor.
Charles Perry P.E.
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phase
By
issue.
give you a

of course.

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