Electromagnetic Fields - some definitions
The energy that builds up the electrical pressure that boosts voltage also builds an ELECTRIC FIELD around any CONDUCTOR (like copper, aluminum, or steel wire) that carries electricity. The higher the voltage, the stronger the electric field.
The movement of electrons, or their energy, through the conductor cause the build-up of a MAGNETIC FIELD around that conductor. Since both electrical pressure and a volume of electrons flow through the wires when a device is turned on, we're usually talking about ELECTROMAGNETIC FIELDS, not just electric or magnetic fields.
Picturing these fields can be a challenge, but the most succinct description I've seen goes as follows: Electric Fields and Magnetic Fields are perpendicular to each other and to the conductor generating them.
- In other words, if you're dealing with a straight wire, picture the wire as the axle of a bicycle wheel.
- Electric fields extend radially, straight outward (like spokes around an axle) down the entire length of wire.
- Magnetic fields only come into existence when power is flowing through the wire.
- The magnetic fields rotate around the entire length of wire, like a series of bicycle rims around the spokes.
- Electromagnetic fields are the combination of these two distinctive but interactive field types.
When you switch on a household appliance, also known generally as a LOAD, voltage causes amps to flow through ALL of the conductors leading from the power source to that device. This means all the way from the device, through its power cord, through the wiring in your walls, floors, ceilings, to the breaker/fuse box, etc. While the switch is ON there are BOTH electric and magnetic fields surrounding the load and all of the wires leading to it. When you turn off the switch there is still an electric field in all of these wires and, quite often, in the device itself.
Electricity comes to us in various types, or what I call its FLAVORS. One of them is STATIC ELECTRICITY, or an ELECTROSTATIC FIELD, which is another term for the build-up of electrical pressure, or voltage. When the static electricity grows strong enough to jump from a doorknob to our fingers we call it a spark. When it jumps from a cloud to a tree we call it lightning. In either case it's no longer static; it moves. Since it moves in one direction it's called DIRECT CURRENT (DC). The most familiar form of DC comes from an ordinary BATTERY, which is a combination of metals and chemicals that react to build voltage and store a fixed number of AMP-HOURS (amps times the time in hours that they'll continue to flow).
If this DC current is turned on and off we encounter PULSED DC. This is most commonly found in the ubiquitous switching power supplies found in computers, DC-DC converters, variable speed motors, dimmer switches, etc. And even lightning usually flashes more than once along an ionized air pathway. All forms of pulsed DC produce HARMONIC frequencies (like octaves in a musical scale) because electrical current reacts rather violently to being suddenly started and stopped.
And if we actually reverse the flow of electrical current (polarity) when turning it on and off we encounter ALTERNATING CURRENT (AC). The most common form, called a "sine-wave" is found in any grid-connected home's wiring. A less common form comes from a low-cost DC-to-AC "inverter". It is called the "modified sine-wave" or "square-wave", where the polarity switching is far less smooth, producing much more "harmonic distortion" of the sine-wave, although almost any AC source will have some higher frequency distortion riding along with it.
The Problem for us:
Some flavors and frequencies of electricity are compatible with humans and other life forms, while some are not. Earthly animals have evolved within a weak soup of EMF ranging from DC to the AC range of 8 Hz - 40 Hz, called micro-pulsations, Schumann waves, Tesla waves, etc. All other frequencies are biologically alien to our bodies.
To see some diagrams and further information describing the entire Electromagnetic Spectrum from DC all the way past microwaves, Click here.
The big problem with transient, pulsed and alternating fields is this:
If a magnetically susceptible metal like iron is nearby, A CHANGING ELECTRIC FIELD GENERATES A MAGNETIC FIELD, AND A CHANGING MAGNETIC FIELD GENERATES AN ELECTRIC FIELD.
For example, if your metal-framed or metal-sprung bed is shoved up tight against a wall that has AC electrical outlets (with "unshielded" plastic-covered wiring supplying them) on it, even if nothing is plugged into the outlets or turned on, your bed is bathed in both magnetic and electric fields caused by the wiring in the wall! The other big problem with electricity in general is that it takes every path it can, not just the ones that we want it to take! For more information on this, scroll down to the note on stray voltage near the bottom of this page.
Solutions for EMF Problems, a checklist:
- Have a qualified installer put non-conductive, plastic sections in your incoming water and drain pipes (even skilled plumbers have been electrocuted while attempting this)
- Use a separate outdoor grounding rod (other than pipes)
- Magnetic shielding (MuMetal, cobalt, or nickel-based metal alloys)as close to the source as possible
- Clustering opposing electrical phases (hot and neutral, or + and -) in metal conduit (EMT or "BX"/ "MC" armored cable)
- Turning off the electrical breaker leading to the device that generates the excessive field, especially at night if you sleep near that field
Low-Frequency Electric Fields:
- Grounded "BX' or "MC" cable, or EMT tubing, metal boxes & covers
- Replacing unshielded cords with shielded power cords, or surround the unshielded cord in aluminum foil seam-sealing tape, which is used to tape seams of foil-based house insulation (but not too near the end you plug in, we don't want any sparks!)
- Reducing proximity and duration of exposure
- Best possible grounding (clean and tight connections)
- Grounded conductive shields (for large areas like the wall near your bed we use aluminum or steel window screen, grounded to a nearby outlet, either on the cover plate screws or ground socket).
- Fluorescent lights, whether tube-type or compact fluorescent (CFL), have a "ballast" transformer or inverter that converts line voltages to 10,000+ volts, creating either a huge local magnetic or electric field. Some LED lights also use either a transformer or DC-DC converter, causing the same problem. Use a meter to check locally-purchased bulbs so you can return them easily if their EMF emissions look excessive.
- Substitute low-emission LED (light emitting diode) bulbs in areas where they are near humans and other animals.
Electrical Noise (Harmonics and Transients):
- Capacitive filters (Stetzerizer, Green Wave, etc.), preferably wrapped and grounded using aluminum or steel window screen
- Tuned frequency filter from equipment manufacturer (call them)
High-Frequency Electric Fields:
- Stick to 3G phones where available since they have a much smaller signal "burst" when looking for a cellular tower.
- Use a "fixed wireless terminal" with up to 5 "land-line" phones, , and a shielded cable going to an external antenna that connects you to the cellular networks (check with your cellular provider - our 3G unit was free and we pay about $24 per month with unlimited minutes)
- Use corded phones when possible, or use shielded phone "holsters" and "air tube" earpieces
- Install wired networks, using readily available Cat-5 cable (if you already have a "wired+wireless" router, just unscrew its antenna and disable your computer's wireless network using its software or use power management to shut it down when not in use - ask a "techie" for help here)
- Shield yourself from the sources (both internal & external), with conductive cloth/screens (for you) or conductive paint, grounded foil-coated foam insulation, or full metal shielding (for your home)
- If the source is within your home and it cannot be turned off or replaced with a wired or manually-read device (especially gas, electric, and water utility "Smart Meters") use grounded metal screening between the meter and the interior of your home so that signals only radiate outward from the home and are absorbed on the house side
More on Grounding and Shielding
There are a number of EMF shielding, filtering, and dissipating products and devices on the market, most of them rather expensive. And although the typical grid-connected home could arguably be greatly improved using any or all of them, simply shutting off the circuit breaker(s) that lead to your bedroom every night is the single most cost-effective solution for eliminating 33% of your electric and magnetic field exposure. Would you rather wake up to music at your bedside or have a good night's sleep? Your choice!
Or putting a shield made from aluminum (or preferably, galvanized steel) window screen on the wall behind your headboard and wiring it to the nearest outlet's ground terminal works well for electric fields (know what you're doing here or find someone who does!). If you don't ground the window screen shield the electric field is reflected at nearly double strength in the opposing direction. If you live in an apartment this could be quite detrimental to your next-door neighbor!
And remember that a bedroom above another floor could be getting electric fields through the floor from ceiling lights and their associated wiring downstairs. Use a meter and check in every direction around your bed! Remember what was said above about electricity taking every path available? Unless all of the potential ways that electricity returns to the power-line transformer are bonded together with low-resistance wire, power will flow back, separately, from the neutral wire (preferred), the ground rod, metal water pipes, metal gas lines, the cable company's ground rod, the phone company's ground rod, metal sewer lines, and even your body if you are standing on a wet floor!
Ideally, all grounding possibilities should be bonded into one grounding point! Check your incoming/outgoing pipes for magnetic fields and, if they are metal, you may find that electricity is flowing from house to house along the water supply mains, gas pipes, etc. It's best to call the "gas man", electrician or plumber at this point, since you will need to splice a non-conductive section into your supply pipes, and possibly move the main electrical box's ground point along the water pipe, or to a separate ground rod. Doing this by yourself could be dangerous, even lethal!
And check your local electrical codes on grounding requirements in your area! Tearing the walls open to rewire with "BX", or as it's also called, "MC" (spiral-steel conduit, metal-clad) or metal EMT (electrical metal tubing), and putting in metal boxes and cover plates isn't a very savory or low-cost option, but it may make sense for just the bedroom receptacles. Installing MuMetal foil (or one of the other magnetic-shielding fabrics/foils) over high-power electrical cables will contain the magnetic fields. And do not forget proximity. The intensity of the magnetic field drops with the square of the distance from their source, and the electric field intensity (from a wire) drops linearly with distance. In other words, move your bed twice as far from that wall with the outlets in it and you've got one-fourth the magnetic field intensity and one-half the electric field intensity at night.
The U.S. Food and Drug Administration has not evaluated any of the information contained herein (nor is it likely to!), and said information is not intended to replace the advice of a physician, nor is it intended to diagnose, treat, cure, or prevent any disease.