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Harmonics

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Harmonics, colloquially named "dirty electricity" by some who want to make a buck by selling you "filters," are whole-number multiples (/echoes) of the input frequency (60 Hz in North America), and are triggered by non-linear (non-smooth) Current usage. The most obvious culprits are: fluorescent lighting (of any type), dimmer Switches, SPS (switching power supplies) / SMPS (switch-mode power supplies), and LED or low voltage lighting fed off of 120 VAC (both of which are fed by SMPS), and they have some peculiar properties:

  1. Since alternating power occurs as bipolar bursts of power (that is, two per cycle), each burst will produce a ringing of the EMF spectrum (trigger many frequencies simultaneously), whose frequency extent will vary with the energy content of the burst, although caused by individual bursts.
  2. Since the bursts are quick enough in time, the harmonics may appear as a continuous stream, when detected by simple devices such as an AM radio, or even sophisticated ones like a spectrum analyzer,
  3. Their aggregate waveforms are able to penetrate insulating barriers more easily.
  4. That is because, like in a capacitor, which consists of two electrifiable plates separated by an insulator, when an alternating voltage appears on one plate, it likewise appears on the other.

Details on fluorescent lighting, in case you lost your notes . . .

Fluorescent lighting is produced by an electric arc through a conducitve gas, a.k.a. plasma, the fourth state of matter, which constitutes most of the universe beyond our atmosphere.

In order for the plasma to conduct, it has to be brought up to temperature, by internal heaters, which is a problem with outdoor fixtures in cold weather, not wanting to light.

Once up to temperature, the plasma requires a certain minimum voltage to begin emitting light. Since the alternating voltage provided to it smoothly travels from 0 to 170 volts, the lamp is initially not lit the moment voltage applied to it begins to increase above (or below) zero. Once the threshold voltage is reached, as shown below (+ or -, as the gas conducts not based on a polarity, but based on the magnitude of the voltage difference applied to it from one end of the bulb to the other), the gas begins conducting producing light, mostly in the UV range. Neglecting the second part, of how the light emissions are frequency-shifted from the UV region to the visible region, the beginning of conduction causes an almost instantaneous surge of demand current. This surge causes a slight dip in the supply voltage, and a very distorted current waveform.

current demand by fluorescent
  1. Since the gas emissions do not fully quench before the next burst of power (less than about 2 ms), the emissions appear continuous, unless the tube is reaching end-of-life.
  2. Since the excitation and de-excitation are statistical occurrences, there is in addition to luminous emissions, low level emissions lower in frequency, in the radio frequency region.
  3. Since the required current does not resemble the applied voltage, a stream of harmonics ensues with each burst of current used.
  4. The harmonics are most noticable on the current, but a very small impact occurs on the applied voltage, to perhaps 1 to 2% of the 120V.
  5. Since in most homes there is wiring that allows an electric field everywhere, this small impact is detectable everywhere in free space.

For those who haven't caught on yet, the process described above is ionization and de-ionization in a plasma (electrically conductive gas), occurring with only about 80 volts or so. Certain physicists would have you believe ionization requires zillions of volts . . . power systems' alternating fields introduce currents within our bodies, not unlike those within the plasma just described. But no, no, no, we're not really being "ionized," so please don't use the term unless we're talking high-energy particle physics!

The ease of barrier penetration is employed in TENS (Transcutaneous Electrical Nerve Stimulators) units that are used to alleviate pain. This is an example of a controlled and beneficial biological electrical application. Similar rapid transitions are employed in TASER guns, used by law enforcement to inflict pain and immobilize. The main difference between the two is the magnitude of the voltage transitions. Many harmonics produced by common residential electrical devices ride on the 60 Hz voltage and can likewise penetrate the skin and interfere with the cns (central nervous system). The cns performs muscle control by electrical pulses (action potential) that are characteristic to the electrochemical messages constantly occurring within the body. When an electrical pulse (or pulses) of similar waveform or repetition (read frequency) is (are) able to enter the highly conductive structure below the skin, interference in the form of irritation, pain, or outright failure to control physical activity may occur. Other pulses wholly within the brain can similarly be interfered with. When these harmonic emissions have a convenient carrier, such as a whole-house alternating electric or magnetic field, then these emissions become immediate and whole-body exposure concerns (a former client wished to use a digital widescreen television, but due to the switching power supply's rapid transitions, and the home's electric fields from structural cavity wiring (Romex) acting as carriers, she could not tolerate it (it was almost as if the emissions were occurring within her anywhere inside the home)) . These are examples of uncontrolled and detrimental biological electrical interference.

While on the topic of barrier penetration, it must be observed that our skin is typically a good electrical insulator. Capacitors are used to block DC, but not AC, because when AC is applied to a capacitor, the alternating voltage on the one plate it is applied appears on the other plate as well. That being said, since we are typically immersed in a whole-house electric field (one conductive "plate"), our skin acts as an insulator, while our internals being fully conductive, mimic the second conductive "plate," causing the alternating voltages on the outside of our bodies to appear within it. In contrast, live-line work employs Faraday suits for those doing the work, and the suit is an exclusion device, covering the employee's entire body and equalizing any possible voltage from any one part of the body to another. In a residential environment, however, voltage sources abound in three dimensions, have different polarities, and different intensities depending on distance, causing not only skin penetration but voltage differentials across the body that can be perceived instantly by some individuals.

A subtle note of interest is that some "experts" try to identify the level of electrical "dirt" using an oscilloscope to display a waveform. They then employ a high pass filter, because they've bought into the idea that only faster harmonics are relevant, and display a second waveform, smaller and fuzzier, on top of the first. In contrast to the sketch to the right, an appropriate evaluation display should include not only the waveform, but a frequency spectrum, the latter shown in much greater detail below with a black background. Note in that detailed sketch the harmonics of greatest strength, and those we may be most responsive to, are closest to the 60 Hz fundamental. These "expert" measurement schemes with the high pass filter and an oscilloscope completely overlook these harmonics, and give the impression of talent to the uninformed, when in fact they need serious technical reeducation. More appropriate visual displays include simulatenous waveform and spectrum displays, such as those shown in the Solar-Benefits document.

The 120V in brown, the

The popularized measurement scheme is shown on the first image to the right, and a simplified schematic shown further to the right, using a CFL in place of the "smart" meter.

complex looking setup simple scheme, once decluttered

It should be noted that the designation of the highpass filter as "the ubiquitous filter" is nothing more than a scam's attempt to gain legitimacy. The test setup 1) simply monitors Voltage, implying that is the only entity of relevance, 2) it omits sensing the lower tier of harmonics, which are the strongest, and most relavent from a Power Quality perspective, 3) it omits harmonics frequency amplitude information, which could be a clue to a fire hazard.

A complementing "authority" suggests there is a need to measure harmonics / de to 400 kHz. For the life of me, I can't imagine why there is this need, when the most relevant harmonics are in the audio range, and any faster presence simply becomes a carrier for the lower ones, much like in Radio. For what it's worth, frequencies between about 50 kHz and 500 khz are allocated to PLC usage in North America. But the "authority" appears to be German, and their recommendations are applied here where they do not apply. So if you are interested in scouting out PLC, in a residential environment, when PLC is really applied in high voltage Bulk Power Transfer, have at it.

When the per-cycle current demand is strong enough, some of these emissions can be easily be detected with an AM radio. A dimmer in use will produce this type of electrical emission 120 times per second (100 times per second outside the USA) and may appear continuous, in time, and frequency, throughout the AM spectrum, blanketing all frequencies in an otherwise quiet background. Put enough of them in use simultaneously, and you'll produce harmonics spanning into the cellular frequency ranges, 600 to 900 MHz.

Some additional thoughts on using an AM radio are located further down the page on detection of SMPS emissions. Although the AM radio gives a glimpse of the higher end of the harmoncis spectrum, a glance at the graph below should highlight a disturbing presence. That being frequencies slower than 60 Hz. Some of these are associated with earthquakes, and some clients noted feeling their floor shaking, followed by observation of wiring in the floor directly beneath them, brain waves, production of seizures, etc. Power harmonics are caused by successive current demand on each 1/2 cycle, so they occur as trains of harmonics 120 times per second. Since the moment the current begins to flow during each 1/2 cycle is not exactly identical as the previous, when viewed in real-time frequency spectrum displays show a vertical wobble for every harmonic. The mere fact that they can be seen immediately leads to the conclusion that they are slower than about 30 Hz, the presistence of the human eye. Anything faster than 30 Hz would be perceived by a human as constant. P.S. the testing scheme above wouldn't give a clue as to any of these frequencies being present, explicitely shown (albeit to only 10 kKz) in the graph further down the page, and easily acquired by an older laptop, and some adequate instruction.

Harmonics and part of their range

Although Harmonics are mostly associated with current ((consisting of as much as 100% distortion from the applied 60 Hz waveform, "the" reference point) this distortion is known as Total Harmonic Distortion (THD) across the frequency region of interest), due to Ohm's Law a marginal voltage signature of these harmonics is produced at the electric panels and then propagated out on all other circuits on the same bus. Nonetheless, the harmonics voltage signature is typically no more than about 3% distorted (from the 60 Hz waveform). Depending on the presence and strength of any locally produced magnetic field, and the presence and strength of the harmonic voltage signature, the AM radio may be reacting to either the magnetic or electric field harmonics signature. Depending on the type of wiring used, and a few key measurements, it will be obvious which is which.

Harmonics in a typical circuit

Dwelling a bit more on Ohm's Law, consider a typical residential circuit shown, the nonlinear load, a CFL, is placed at the end of the circuit. The impact on the voltage gradually reduces on its way to the source. That's because Ohm's Law deals with a voltage produced across a conductor from the source to the load due to its resistance and current flow. At the point of use, there is the greatest electrical resistance between the CFL and the source due to the length of wire to the panel. Should the CFL be placed halfway in the circuit, the gradually reduced voltage impact would only exist between it and the panel. In the other direction, the voltage impact would be greatest and without reduction, because that is not where the current is flowing through.

This has two implications. First, if you are dealing with a charlatan "inspector," it is likely he/she will go from room to room and measure the varying presence of electrical "dirt" at most outlets, with some meter that gets plugged into them. This is a waste of time, and evidence that they do not know the basics of electrical fundamentals. Funds paid to such a person will determine how much of a fool you've been made of, depending on the amount charged.

Second, anything further from the CFL, in the direction away from the panel, as if the CFL was plugged halfway in the circuit, or worst case scenario, into the first outlet near the panel, will experience the same THD along that entire section of circuit. This is most relevant in the case of a digital power meter, because it will have a decreasing impact on voltage on the way to the transformer, but everything indoors will have the same THD as at the point where the meter draws its power. Since this is central to every circuit in a home, every circuit will be impacted to the same extent as at the point of use. While most consumers may be concerned about the RF emissions from a digital mater, these are generally directed outward from the home, and can barely be detected indoors. In contrast the harmonics from these digital devices can be most relevant, depending on the level of the meter's onboard harmonics filtering, or lack thereof.

"Smart" or Demand Metering

Although digital or time-of-day-consumption-recording meters seem at present to some to be evil incarnate, these "smart" or demand metering or automated meter reading (AMR) has been around since long before personal computers came along. They have been used by the electric utilities to monitor large customer usage to identify their peak power usage times and duration, reactive power content, their total consumption for revenue purposes, and to coordinate additional power generation as needed to meet demand. These applications consisted of dial-up connections where a computer would dial through a voice-grade phone line that was connected to a meter with a modem, and once a connection was made, the various data points requested were downloaded to the big mothership. For those old enough to remember, Internet access used to be pretty much the same.

However, the desire by some for consumer usage information, and the consumer desire for lower utility rates, have cornered the utilities into identifying the means of satisfying both needs by reducing personnel (meter readers), and rolling out large-scale application of automated metering. While this automated metering can be applied to water, gas, electric, and other services limited only by the imagination of the design engineer, the ones of most interest to the reader seem to be those applied to electric power usage, which will be the focus here (the concepts described apply equally to all utilities' AMR, except for metering on the powerline). Bear in mind, that unless you are fully d isconnected from the infrastructure grid, you have a contract for services with several utilities. This contract may severely limit your desire of not having automated metering applied to your services. While their use poses valid privacy concerns, whereby your usage can be tracked to identify your daily activities with excellent accuracy, that is entirely another matter beyond the scope of this document.

Many permutations of AMR exist, in a non-exhaustive list as: 1) wired to the power system with direct modulation, 2) wired to the power system via powerline carrier (PLC), 3) wired via telephone line, 4) wireless activated by drive-by (Mobile AMR), 5) wireless by peer-to-peer (mesh) networking. Any of these can provide data collected daily, hourly, minute by minute, or every data collector's dream (not presently available, but on the drawing board) - real-time data.

Note that in a typical home there are many wires scattered about, sometimes resembling the bars of a birdcage, all energized and emitting electric fields 24/7. Critics will immediately argue that there's not enough signal to elicit biological response. However, the body can respond to the frequencies as well as the intensity, so "windowing" effects can be identified, even at very low levels.

In all of this, bear in mind that the entire gist is to perform the same function in a less expensive way - we wanted it this way, and therefore the utilities are constrained into providing it this way. While this may be a good motive, the consequences may be undesirable, and once in motion, there may be no reverting back as utilities cannot (and will do their utmost to not) cater to each individual's desires or needs, as this would cause cost increases that would have to be passed on to the consumers, them being us.

The faster data is collected and passed on, the more data can be collect and processed. The data collected can quickly identify living habits of the user, and open them up for pointed marketing from the utility or those to whom the data is sold. The data can be sold to whatever market is available.

Should you wish to attempt to keep your home, neighborhood, or town AMR-free, then your only recourse may be your elected officials or the boards that have jurisdiction over the various utilities. You can state your desire, or demand, to not have AMR installed, realizing that it will in the end cost you more to keep the human meter readers employed.

Unfortunately, harmonics may also be provided with the supply voltage from the utility, despite the reduction of impact from each customer's usage on the way to the supply transformer. While an IEEE suggested limit is 3% for any one harmonic, and 5% for an aggregate sum, the level may be higher. The same IEEE standard (519) recognizes: "the responsibility that users have not to degrade the voltage of the utility serving other users by requiring nonlinear currents from the utility. It also recognizes the responsibility of the utilities to provide users with close to a sine wave of voltage." My measurement of THD in the incoming voltage with a Picoscope was over 5% at client's residence, yet the utility engineer, supported by a $10,000+ Dranetz could not determine any to be over 3%. Data falsification due to vested interest? Operator error?

While harmonic emissions are easily controllable at the source, or by appropriate filtering, some unscrupulous marketers are selling plug-in "filters" of various sizes with the claim to "clean" "dirty" electricity. While clean electricity is continuously varying with time, and in and of itself is an irritant, harmonic energy riding on the ACV can be especially irritating. However, indiscriminately installing filters without investigating the residence's electrical system, and verifying there are no wiring errors, will cause more harm than good. Interestingly, these consumer-applied "filters" produce harmonics of their own. So their installation is a mixed effect, in that some are reduced, some are not impacted, and some are increased.

By exposure to Harmonics, the central nervous system may meet with electrical waveforms that have similarities to its own messaging, causing interference (pain, irritation, etc.). In reality any system that allows alternating electric or magnetic fields (the carrier of the electrical "dirt") to occur in free space has the same "dirty" characteristics, even if it is an absolutely smooth (sinusoidal) waveform. So electrical "dirt" is just a marketing name for a feature of the electrical system that has been in existence since its inception, and buying some gimmicky "filters" will not "harmonize, or clean" your living space from it / them.

With the advent of modern electrical devices, many are found to produce lots of electrical "jitter" / waveform distortion (due to non-linear current consumption), or what I will refer to as "electrical noise", but more classically defined as EMI (ElectroMagnetic Interference).

Cautiously Getting Free Help

The local electric utilities are obligated to provide the user with clean alternating power, generally within +/- 4% of 120 V, and generally free of offending EMI. If there is offending EMI, they have an obligation to fix it, at their own expense, until the customer is satisfied. This is generally written within their tariffs relating to "power quality," region by region. If you are certain you have isolated, or otherwise de-energized all your customer-owned SMPS, and there is still EMI coming from the utility, as notable from the breaker panel being a "screamer" even with the breakers open / off, then by all means call your electric utility and take them to task. What EMI consists of and what it can offend varies greatly, and telling them it hurts your brain will get you nowhere quick. But getting familiar with the lowest intensity AM broadcasts (those from far away), and having intolerable interference with their reception will "get their goat." They may suggest listening to noise-free FM, but who knew that those sensitives were aficionados of far-away AM? And shamelessly borrowing from Arlo Guthrie's Alice's Restaurant Massacree, where he was talking about the Draft: "You know, if one person, just one person does it they may think he's really sick and they won't take him. And if two people, two people do it, in harmony, they may think they're both faggots and they won't take either of them. And if three people do it, three, can you imagine, three people walking in singin a bar of Alice's Restaurant and walking out. They may think it's an organization. And can you, can you imagine fifty people a day, I said fifty people a day walking in singin a bar of Alice's Restaurant and walking out. And friends they may thinks it's a movement." You have lots of power, when you cautiously use their own guidelines against them, and a movement is easy to start if enough individuals participate. If you find this material useful, share it with others, and help them along and yourself. But realizing that utilities have more pressing issues, like emergencies, be kind to them, but persistent until you get satisfaction. If it turns out to be your "smart" meter, they may have no choice but to replace it with a less offending one. Be alert also, that if you call them and they identify your equipment as being the cause, your credibility and their obligation toward you may evaporate instantly. Also be alert to the possibility that getting the utility involved, and several customers being supplied in common, a blatant EMI producer may turn out to be one of your closest neighbors, who may be unpleasantly alerted by the electric utility of the need to temporarily disconnect them to identify the source of electrical noise. This could shift some neighbors away from being friendly. Act tactfully!

Issues with dirty electricity "filters"

I am going to use an analogy with water that may hopefully clear up the matter.

We've lived in our home for over 20 years, and for 19 of them our water supply line meandered for about 300' through two other properties, before it met up with the water main in the street. 60 years ago, there may not have been houses on the lots where our pipe meandered through.

Be that as it may, one problem was that whenever our neighbor flushed their toilet, we would lose pressure. This is akin to a machine shop or garage down the street turning on some large compressor, and your voltage (and all lights in use) dim, and slowly come back up in intensity. Locally within your own home, you should be able to notice this every time the refrigerator comes on.

Another problem was that the 300' of pipe was internally flaking. That is, pipe slag would come into our water system. This was particularly annoying, because the pipe slag would land in the clothes washer, and cause rust stains on our clothes. So I installed a 5 micron filter to remove the pipe slag.

I could have used a Parallel "filter," as shown below.

Parallel in piping

This is the same way that all dirty electricity filters (Stetzer's, Greenwave's, and Quiet Island's Capacitive), and now "dissipative" filters (DNA's) are installed. Even assuming there is some flow through the "filter" (as with the leaky water valve above), I still cannot imagine for the life of me that the pipe slag would have been magically absorbed exclusively into the filter, and not also traveled through the other pipes _ and the clothes washer. However, all these electric "filter" marketers are profusely asserting that this is exactly what happens with electrical "dirt." These claims defy laws of physics, and the real world, and are more than anything faith-based gimmicks or "magic." I have other words for them, but I'm trying to remain polite.

Instead, I installed my water filter in a Series arrangement, as below.

Serial / Series in piping

And you know what? The pipe slag was stopped entirely in the filter. Because we had an ongoing collection of this slag, we had to change the filter on a regular basis. An appropriate electrical filter in this application would not need to be changed, unless the exterior contributions dramatically change for the worse. Unfortunately, a proper electrical filter of this type can cost thousands, and would not eliminate your own contributions, shared internally within your home. Call it capacitive, dissipative, or whatever, this is a scam instituted against the unwary.

Stetzer came up with the novel GS unit for "dirty" electricity, and only his meter that can read them. Convenient.

Greenwave pointed out the obvious, that GS units don't exist in the real world, and promoted an alternative measurement scheme (scam) of their own, mV (millivolts).

IBE (the Institute of Building Biology and Ecology) initially bought into the "filter" concept because they thought there was money in it, and since they've always been hurting for money, and since many of their students are technically "green," the latter bought into it, lock, stock, and barrel. So hiring a Building Biologist (BBEC) to assess, and possibly suggest solutions for "dirty" electricity is a throw of the dice, unless they've received additional technical training on their own. However, once certificated, these individuals have no interest to be further educated. If you are a client, and after having read these pages meet up with one of these and find dissatisfaction, set them straight. Who knows, they may choose additional knowledge, some here free for the taking. In any case, unfortunately, the alternative is to buy into some of these "filters" on your own, and hope for the best.

There is a standard to measure and quantify harmonics / "de," but that is not what IBE teaches, either because they don't know, or because they think their students are too ignorant to be taught this concept.

Capacitve filter Harmonics

Shown above is a spectrum of the current through a capacitive "filter" on a clean system, showing that it introduces "dirty electricity" all by its lonesome. That's because the necessary geometries used in the construction of these devices, makes them complex resonant circuits, and being fed pulsed energy, a resonant circuits rings electrically, like a bell does mechanically. But since the 60 Hz system sends pulses to these devices 120 times per second, the ringing continues, and when looked at in real-time on a spectrum analyzer, the frequency presence of the harmonics appears "constant." I don't see the DNA "filters" to be anything different than other "capacitive filters," other than flowery "dissipative" wording. They, like others selling these "filters," simply see a money stream from a bunch of suckers (gullible public), and want their share of it.

The behavior of devices marketed as "dirty electricity filters," which are nothing more than capacitors, when exposed to a changing waveform, is to convert the impressed changing voltage to changing current flow, the amount of current flow determined by its electrical capacitance value. Additionally, since no capacitor is perfect, such a conversion will add harmonics that are solely generated by the capacitor. This current is then partially impressed onto the electrical system ground (ESG) / neutral, which, albeit "grounded," will develop a voltage directly proportional to the amount of current used (whether from capacitor filters alone or other devices), due to the physics relationship described by Ohm's Law, that is now made available through every cable within a residence, as described above.

So a capacitor filter, by whatever name, will suppress some harmonics, and add some of its own, which is not a "cleaning" effect. So anyone who tries to sell you a capacitor "filter," without telling you all of the implications, is uneducated at best, or a robber waiting for a chance to take your hard-earned resources at worst.

This EMI is impressed onto the supporting power system. The power system, being what it is, allows circulating currents that should not exist, but do, because of wiring errors, redundant neutral current paths, and system degradation over time. Since the typical electrical system is not subject to regular inspections, these problems can exist for years (or decades) undetected, possibly causing biological damage, or possibly more immediate physical damage (such as death) due to maintenance on related systems that "unexpectedly" carry some of the shared neutral current.

The associated problems are typically 1) Neutral to Neutral wiring errors (with any type of wiring system, including knob-and-tube), 2) Neutral to Ground wiring errors (with either Romex (NM-xx-x) or BX/MC), or 3) conventionally shared Neutral paths between adjoining users (with any type of wiring).

Graphically, isolated detached errors between two or more circuits exist as follows:
(with only the neutral (return) wire shown for clarity)

basic wiring error
wiring error effects

The magnetic field (when there is one) will exist and broadcast into free space regardless of the wire type. This shows a wiring error regarding lighting, which may be more common than for power circuits. Nonetheless due to uncle Floyd and cousin Jack doing "creative wiring" over the years, any type (and mixture) of circuit can be involved.

Field Types

Wiring Scheme Normal Operation Emissions Wiring Errors
Knob-and-Tube wide-area Electric and Magnetic wide-area Electric and Magnetic
NM / Romex wide-area Electric wide-area Electric and Magnetic
BX / MC No emissions wide-area magnetic
Redundant Neutrals wide-area magnetic wide-area magnetic

If there is EMI associated with a cable, it will broadcast unimpeded into free space via other interconnected circuits as an electric field component if the wiring type is either knob-and-tube or NM (Romex), even when those other circuits are not in use. If the circuits are in use, then the EMI will additionally become manifest as a magnetic field component regardless of the wire type installed. Of repeated note should be that harmonics on voltage (producing an electric field) may only constitue 3 to 5% of the electric field, whereas the harmonics on current (producing a magnetic field) may constitute as much as 100% of the magnetic field, making the latter much more irritating (or capable of irritating), when it occurs. All "dirty" electricity filters, by definition, only address the voltage harmonic content (that 3 to 5%, the tip of the iceberg, as it were), suggesting that somehow muddling an effect onto it, makes all things better.

emc filter

A proper EMC (electromagnetic compatibility) series filter is shown above. The filters commonly sold as "dirty" electricity filters, are simply the "across the line" capacitor as shown in the sketch, a rather incomplete application. Proper filter application would have the power (supply and return wiring) go through the filter, not in parallel with it, as with all capacitive "filters" sold. If any type of capacitive filter is installed in an attempt to ameliorate the EMI, without the knowledge that there is a wiring error, then the formerly intermittent field will exist as a magnetic field component continuously regardless of the type of wire, and as an electric field component, depending on the wire type. That is because a capacitive filter will, by virtue of its physical characteristics, change a portion of the voltage pulsations (depending on frequency) impinging on it to current pulsations. So the process fundamentally involves a conversion, not an elimination.

Various capacitive filters are available. Some allow five amps per filter, some allow one amp per filter, and others allow a current based on whatever the individual capacitance value is, and how many are installed in the circuit. Thus the magnetic field presence can vary by the various factors just noted.

Capacitors used for Power-Factor Correction

A characteristic of alternating power is that the power conveyance system (the transmission and distribution systems) and load systems are somewhat elastic, in that as voltage is applied, the current does not flow immediately at the same instant, but a short time after (somewhere between 1 and 3 milliseconds). While this may seem like a small value, and it is, it can have a big financial impact on the producer and the user. The reason is that ideally both want the same amount of power produced as is being used, instantly and continuously. However, the small amount of time delay allows circulating currents known as volt-amperes reactive (VARs) which, depending on their amount (and whether they lag, or lead the applied voltage) can help provide system stability, reduce system efficiency, or bring about a system collapse.

The time delay occurs because most user loads have inductive elements. That is, the electrical qualities that foster the buildup of voltage but hamper the passage of current (such as motors or transformers). With too much inductance, the voltage begins to drop because there is too much opposition to flow between the source and the user. One of the remedies is to add capacitive elements. These devices foster the passage of current, but hamper the buildup of voltage. As capacitive elements compensate for the inductive elements, the conveyance system becomes more efficient, and the voltage goes back up. Power System Operators (of which I was one for six years) customarily bring large capacitors (7,200V to 230,000V) online regularly and daily to boost voltage when it begins to sag, and do the opposite when it begins to go too high.

Electricians have known about capacitive elements for a long time, as they are used to start motors, and are used to improve the efficiency of the power usage in large buildings. Even in a private residence of substantial size (5000 square feet, or 400+ amps load service rating typically, or bigger) capacitive elements may be added to improve the usage efficiency. With improved efficiency, and reduced time delay between voltage and current, the user is closer to consuming more real power (watts), and causing less reactive power (VARs).

However, the insertion of capacitive elements (capacitors, "filters", etc.) within a home of average size is not warranted, as no improvement in power usage is realized, and owing to the built-in problems that may have gone unnoticed for years, the situation will most likely be made worse rather than better. Considering that electric and magnetic components have biological impact capability, it is unconscionable for any individual or firm to market them without disclosing the very likely negative impact.

Granted, in the example shown it would be difficult to apply capacitive filters because the circuits are strictly for lighting, but mixed-use (power and lighting) circuits exist often enough that any one circuit may have filter attachment capability (outlets).

neutral shared with neighbors

The above sketch shows the interconnection between the electrical system ground, which can consist of any number of metallic structures in contact with the soil, and a metallic water pipe. Note that a magnetic field depicted exists regardless of whether the house shown is using any power (if it is located in a residential neighborhood where several homes are fed off the same power transformer). When the house shown begins to use power, it may add to, or subtract from the current and magnetic field, depending on which bus is flowing current at any moment, because the polarities may be opposite or alike.

The size of the field may be sufficient to engulf the entire house.

Adding any capacitive filter into any circuit, will have the effect of producing a continuous current flow which will be split between the electrical system neutral and the water pipe. If there is no other NET (uncanceled) current in existence, one will be created. If there is NET current in existence, then the newly added one will either add to, or subtract from it, possibly varying in direction and intensity from any moment in time to the next, depending on the polarity of the electric source (which will determine in which direction the current is generally flowing).

In any case, the current produced by insertion of a capacitor of any size is non-Linear. That is, if you feed it 60 Hz (50 Hz) voltage, the current produced has many frequency components in addition to the original frequency. In light of this, application of a capacitor is not inconsequential, it makes the electricity, it is meant to clean up, "dirtier!"

plumbing currents

When several homes are fed from the same power transformer as above, even if the water pipe and electrical service are located on the same side of the house (an ideal situation that could reduce the wide-area impact of split neutral currents), a magnetic field may exist from water piping in the street that could negate any of the considerations presented here, in that even neutral isolation would not accomplish a substantial reduction of the magnetic field presence.

While the insertion of any capacitive filter may have benefits in reducing some type of high frequency (HF) EMI, as is their claim, their insertion needs to be carefully considered in light of any possible wiring errors, or even normal installation characteristics (as shown with the shared (or interconnected) neutrals) which could produce undesired magnetic fields. Another "trivial" detail not usually mentioned is that their insertion can cause a fire due to harmonic resonance.

As a general rule capacitive filter installation is not recommended,
without a thorough evaluation of the electrical system to
:

1) identify and eliminate any wiring errors, and

2) not recommended if the neutral current takes many divergent paths as shown in the house with the electrical service at one end of the house and the water pipe at the other end, and

3) not recommended if there are any other local options (like removing dimmer switches, replacing compact fluorescents or fluorescents in general with standard lamps, reducing the number of digital devices, etc.) available to eliminate the problem.

Irritating harmonic or transient phenomena can manifest themselves through the auditory, visual, tactile senses, or directly by EMF interaction with the cns.

When one considers the benefit of shielding from artificial sources, one needs to consider that shielding is a trial and error exercise, even with "competent" engineers. So if a consultant suggests large-scale shielding efforts, walk the other way _ fast. Proper investigation involves looking at the audio spectrum, where the strongest harmonics reside, which can be done quite inexpensively, as anything faster becomes a carrier for the audio range harmonics, and using expensive or expansive equipment to look at a much wider portion of the frequency spectrum is a waste of time and money, and is most usually not necessary.

Some Indoor Solutions, in order of increasing cost:
1) replace any compact fluorescent lamps with incandescent ones,
2) limit the use of conventional fluorescent lamps, or replace with incandescent ones,
3) limit dimmer switch usage,
4) replace dimmer switches with conventional ones,
5) limit usage of line-powered digital devices (SMPS), including computers,
6) when using digital devices such as computers, use on battery, or use shielded cords,
7) use 120 V Quartz Halogen lamps (modern incandescents), commonly available in various wattage sizes.

Some Outdoor Solutions:
1) identify sources and if owned by the electric utility, have them repair same.