How to wire a house for low EMF
Part 2: the specifics
Electromagnetic (EMF) radiation from household wiring can be drastically reduced by good design and wiring practices. This is part 2 of a two-part how-to article.
Keywords: EMF, EMR, radiation, house, home, wiring, design, reduce, protect, shield, electric field, magnetic field, healthy house, electrical sensitivity
This article is a catalog with detailed information on how to minimize radiation from the electrical system in a house or apartment. The methods can be used to modify an existing home or when building a new house.
The information is intended for homeowners and electricians. A homeowner can use this article as a basis for discussion with an electrician.
The examples use materials and practices from the United States, but we have tried to write the text so it is usable in all countries.
Not all suggestions are needed or feasible in all situations.
This is part 2 of a two-part article. Part 1 covered basic information needed to understand these instructions, and why they work. It also dispels some myths and misunderstandings that are commonly believed — even by some electricians. Please read part 1 before proceeding.
A separate meter pedestal
It is best to have the electrical meter on a separate pedestal that is a bit away from the house (perhaps 30 ft/10 meters). The front of the meter should point away from the house (by at least ninety degrees).
Most electrical meters have wireless transmitters in them, or will be replaced with one in the future. They radiate mostly out the front of the meter, hence the need for the meter to point away from the house.
The buried cable from the pedestal to the house should also dampen any microwave frequencies travelling along the cable from the meter’s wireless transmitter. (The buried cable will not really help on the lower frequency dirty electricity from the meter’s electronics.)
The pedestal should have a small electrical panel with a master breaker, a ground rod and a neutral-to-ground connection (“bonding”). This feature may reduce the amount of ground current around the house, unless the house is in a dense neighborhood where the ambient level is already high.
For apartments it is best if the bank of meters and electrical panels is on the wall to another apartment and at least 30 ft (10 meters) away.
The main electrical panel
The main electrical panel (or “breaker box”) controls the electricity as it enters the house from the outside. Most homes have just one electrical panel, but apartment buildings and large homes may have additional sub-panels.
The electrical meter is usually mounted on or next to the main panel.
The main electrical panel has one or more breakers that can be used to shut off the electricity to the entire building. It is also where the “neutral” wire is connected to the ground, called “bonding.” More about this later.
The main electrical panel should be mounted on the same exterior wall where the electrical feed enters the house. It should not be mounted in the center of the house.
The panel can be mounted on the inside or the outside of the wall. It is usually best to mount it on the outside, especially if it has an electrical meter on it (wireless meters radiate mostly out the front).
Most building codes require the main electrical panel to have a connection between the neutral and the ground wires, and down to a ground rod. This is called “bonding.” Unfortunately, this provides the electricity with an alternative path to run from the neutral wire, down the ground rod, through the soil and back up another ground rod somewhere else. Electricity always runs in complete circles, it doesn’t disappear into the ground. This setup can cause ground currents and unbalanced circuits, which can raise the level of EMF in and around the house.
See Part 1 of this article and the book Tracing EMFs in Building Wiring and Grounding, by Karl Riley for a more detailed explanation.
Make sure the main electrical panel is of the type that can be configured as either a sub-panel or a master panel. These panels may not be available at your local building supply store. If not, try an electrician’s supply store.
Such a panel will have:
Š separate bus bars for neutral and ground
Š the neutral bus bar is insulated from the steel box (chassis)
Š a removable screw or bar connects the two bus bars
Using such a panel gives you the option of separating the neutral and ground there, to reduce ground currents. This works best if there is an electrical pedestal with the master breaker and ground rod a bit away from the house. Then the required bonding can take place there instead (some inspectors may not be comfortable with that, though).
Do not mount electrical panels in contact with metal studs
If a breaker box is mounted in contact with metal studs, it can create a path for electricity to return to the panel via the studs instead of via the neutral wire (or ground wires).
Use some sort of plastic or wood spacer, and no screws that touch both the electrical panel and the studs. Or use a wooden stud.
In some countries the breaker panels are of plastic, so this is not a problem there.
Apartment buildings usually have separate electrical panels with breakers for each apartment. Large homes or homes that have extra rooms added onto them may also have extra panels.
Any panel that is not the main breaker panel is a sub-panel.
A common mistake is that the sub-panel has a connection between the neutral and ground (“bonding”). It is very easy to make this mistake, since the panels usually (perhaps always) come with the bonding in place. Many panels do not have the ability to remove the bonding and not all supply stores even carry the ones that can. A true sub-panel has these features:
Š separate bus bars for neutral and ground
Š the neutral bus bar is insulated from the chassis
Š a removable screw or bar connects the two bus bars
It is against the U.S. building codes to have bonding on sub-panels because it will make the grounding wire between the sub-panel and the main panel carry electricity (in parallel with the neutral wire).
Bonding in a sub-panel can cause electricity to run in strange places that are connected to the grounding system, such as water pipes, metal studs, metal air ducts and many other places. Very high electrical and magnetic fields have been the result, but since electricians and building inspectors don’t carry gauss meters, these problems are rarely discovered.
Wiring a three-way circuit
A three-way circuit is often used in hallways, so the lights can be turned on and off from each end. This is done with toggle switches instead of regular switches.
Some electricians cut corners and wire the circuit by connecting each toggle switch to the nearest circuit they can find (which are likely two different circuits) and string a two-conductor cable between the two toggle switches.
With such a setup, the current will arrive to the first toggle-switch on one cable, go to the second toggle-switch and then return to the breaker panel on a different cable.
Since the current does not return on the same cable, the circuit will radiate much more than it should (see Part 1 of this article).
Also, since the neutral wires of the two different circuits are connected to each other, more EMF problems can happen. Electrical currents from other appliances on these circuits may also travel across the link between the two circuits to cause further unbalance and radiation.
The U.S. National Electric Code (NEC) forbids crosslinking neutral wires from different circuits.
The correct way to wire a three-way circuit is with a three-conductor wire. Any electrician’s handbook should have the diagram. It is simple enough to do correctly, but some electricians like to do it the bad way because it is a little simpler and they don’t have to go pick up a piece of three-conductor wire. For them to see, their little short cut works just as well.
Beware of wall boxes serving more than one circuit
Sometimes there are wires from two or more circuits going to the same wall box. This may happen when there is a row of switches in the same wall box.
It is easy for the electrician to just connect all the neutrals together right there. He may do it automatically, not thinking they are different circuits. It may simply be a bad habit. It seemingly works fine that way, so why not?
But the crosslinked neutrals from different circuits can create horribly unbalanced circuits, with high magnetic fields. And it is against the U.S. National Electric Code.
Keep neutral and ground separate
The neutral wires are connected to the ground in the main breaker box (bonding) as mentioned before.
Since the neutral wire is connected to the ground, some people think of it as a sort of alternative ground. It is not. Horrible problems with magnetic fields have been created because the neutral wire was connected to other neutrals or ground wires, or even studs or metal pipes. This has created alternative paths for the electricity and thus unbalanced circuits.
Routing the wires for less EMF
The radiation from the wires is reduced by distance. Just adding an extra foot (30 cm) of distance can make a big difference.
When installing or upgrading household wiring, consider routing the cables to keep them further away from places where people spend a lot of time. This is especially important around the bed. Avoid installing cables crossing under the floor or over the ceiling; instead follow the top of the walls.
Twisting the hot and neutral wires around each other enhances the shielding effect of having the two wires run close together (see Part 1). Twisted wires are commonly used in cables for computer networks and telephone cables. It is not commonly done for household wires, though doing so reduces the magnetic field by about 90% (this is not as impressive as it sounds). Twisting the wires does not reduce the electrical field.
Cables with twisted wires can sometimes be bought ready-made. In America, some brands of three-conductor cables (12/3 and 14/3) are already twisted — not because they reduce the EMF, but for production reasons. Close inspection of the cable will show if the wires are twisted under the protective sleeve. The extra (usually red) wire is simply not connected to anything, or could be connected to ground in the end closest to the breaker panel (do not connect in both ends).
It is simple to twist your own wires, using a variable-speed power drill. Measure how long the cable needs to be, then cut off a piece of cable that is about 20% longer (because it will shrink from the twisting). Mount one end of the cable in the chuck of the power drill (instead of a drill bit) and attach the other end to a tree or let a helper hold it. Then slowly turn the drill so the whole cable becomes twisted.
About one turn per inch (25 mm) is good. Do not twist it too tight as that would make the insulation thicker and possibly cause the cable to overheat in extreme situations (max current on a hot day).
Shielding the wires with aluminum foil
If the walls of the house are covered with aluminum foil, it will also shield the electrical field from the wires in the wall. It will do that regardless whether the foil is grounded or not.
Thin aluminum will not shield magnetic fields, but if the wires are also twisted then both the magnetic and electric fields will be reduced.
Shielding the wires with steel conduit
Encasing the wires in steel conduit shields both the magnetic and the electric fields, but at a much higher cost. It takes a lot of extra labor to install metal conduit.
In America, the EMT conduits work just as well as the heavier IMC conduits. EMT is better than the flexible MC (metal clad) cables because MC does not make a tight connection with wall boxes.
When pulling conduit through walls with metal studs, it is best to insulate the conduit as it passes through each stud. This can be done by wrapping a short length of garden hose around the conduit, or with some other kind of flexible and durable plastic. Steel electrical boxes should also be insulated from the studs they are mounted on. This all reduces the possibility of stray electricity.
It is possible to replace the wiring in an existing house, though it may be difficult to access some areas. It may be necessary to install exposed conduit either on the inside or outside of a wall. Sometimes cosmetic covers can be installed to make it look nicer. Some wiring may not be needed and can simply be disconnected at the breaker panel.
If steel conduits are not available, water pipes of steel or copper can be used instead.
Switching off circuits
If the breaker is turned off for a circuit, it is no longer energized. This can reduce the magnetic and electrical fields in a room. Some people keep the breakers off for their bedroom for that reason.
There are electronic switches available that automatically disconnect the electricity to a circuit when it is not needed and turn it back on when needed again. These switches are installed in the breaker box and work by placing low voltage DC electricity on the wires to detect when a lamp is turned on. It may be acceptable to install one of these in a rented apartment or house.
All breakers and switches turn off the “hot” wire, but not the “neutral.” Disconnecting just the “hot” wire greatly reduces the electric field, since the neutral wire carries a very low voltage (usually just one volt). However, leaving the neutral wire connected can still be a problem.
The neutral wire sometimes has a higher voltage on it, especially in large apartment buildings and office buildings. The neutral wire can also carry “dirty electricity” that radiates off the wires, even at a nominally low voltage.
The best protection is to install a “kill switch,” which is a double-poled switch that disconnects both the hot and the neutral wires where they enter the room, so all the wiring in the room is isolated from the grid.
The switch looks like an ordinary wall switch and is usually located by the door. The electrician should make sure to route the cable carefully, so the part before the switch doesn’t run along or across the room, since this part of the cable will still radiate when the switch is off.
Kill switches are mostly installed in bedrooms, since that is the room that needs the lowest EMF level. If more than one circuit serves the walls around the room, they must each have their own switch.
Do not allow any light dimmers anywhere in the house. They all work by rapidly turning the power to the light bulb on and off thousands of times a second. This creates powerful spikes in the electricity (dirty electricity) that can travel on the wiring to every room in the house, even those on different circuits.
It is best to install regular light fixtures, as they provide the most flexibility to avoid unhealthy light sources — now and in the future.
Avoid installing fluorescent light fixtures. Those kinds of lights and their ballasts are a problem for many sensitive people.
Avoid 12 volt track lighting. The built-in transformer produces EMF and “dirty” 12 volt DC (i.e. DC electricity with high frequency spikes). Some of the tracks widely separate the plus and minus, which means they may radiate more powerfully. (12 volt DC electricity from a “clean” source, such as a low-EMF DC-only solar system without any inverter or converter, is healthier than AC electricity.)
Ground fault breakers (GFCI/RCD/FI)
The building codes in the United States specify that electrical outlets in “wet” areas (kitchens, bathrooms, porches, etc.) must have special GFCI (Ground Fault Circuit Interrupt) outlets to protect people against electroshock. These are also called Residual Current Devices, RCD.
These GFCI outlets contain electronics that control the breaker. Their electronics radiate all the time, whether the outlet is used or not, and regardless whether it is tripped or not. Some models have better designed electronics that radiate much less than others. The Cooper brand has for more than a decade been the best (at least as of 2016).
Another measure is to put each GFCI on a switch, so it is totally off when the outlet is not needed.
Building codes often require outdoor outlets to be GFCI protected. If these outlets are on separate breakers (which is common), the breakers can simply be left off when not needed.
In parts of Europe it is common to have switches for each outlet and use whole-house versions of the GFCI (called RCD or FI in some countries).
The arc fault (AFCI) breaker
Building codes in the United States started requiring arc fault breakers in 2008. These AFCI (Arc Fault Circuit Interrupters) are required to protect any circuit that serves a bedroom.
The AFCI has a tiny built-in computer that monitors the line voltage to detect arcing (i.e. tiny sparks that could cause a fire). AFCIs are installed in the breaker box, not in the outlet boxes.
We have tested one brand of AFCI breaker and found it was more radiant than most GFCIs. Some brands may be better, but you’ll have to buy one that fits the breaker panel.
Since the AFCI is mounted in the breaker box, it may be acceptable to have it there. An option is to disconnect that circuit. Another option is to install a regular breaker, once the house has passed inspection and accept a slightly higher risk of a fire.
Metal walls, foiled walls
Some MCS houses have walls covered with plates of steel or aluminum foil. If such walls accidentally become energized, the electrical field in the house will greatly increase and people can receive electric shocks. The walls can be accidentally energized in a variety of ways, such as by hammering a nail into the wall where it hits an electrical wire and brings it into electrical contact with the metal wall.
The conventional protection is to connect the metal walls to the house wiring’s ground, perhaps through the ground prong on one or more electrical outlets. If the walls become energized, they will immediately short to ground and trip the breaker.
Another common way is to use steel wall boxes for the electrical outlets and ground the walls through every single outlet box.
Both of these two methods may turn the walls into giant antennas that radiate whatever “dirty electricity” frequencies are travelling on the house ground wires. There may also be weak currents running from circuit ground to circuit ground across the metal walls.
There are some alternatives:
1. Protect all outlets in the room or house with GFCI/RCD/FI, so they will detect any problems. This may not solve the nail-in-the-wall scenario, though.
2. Connect the walls to separate grounding wires that go directly to the ground rod that also serves the main breaker box. This can still dump frequencies on the walls.
3. Connect the walls to a totally separate ground rod. This is not as good at detecting a short and may not pass inspection in some areas.
4. Not connecting the metal walls to anything at all and accept the small extra risk. Several houses have these “floating walls,” and the inspectors are not likely to notice.
5. Have the walls not connected to anything and then install a custom built device that instantly connects the walls to the regular electrical ground if the wall potential rises about 10 or 20 volts. This is a new and untested idea, but the most elegant on this list. A building inspector is unlikely to understand and approve this method. The needed device is not available commercially and not approved by any authority.
It is best to use plastic outlet boxes rather than steel boxes, since the steel boxes will need to be grounded and it will be difficult to ensure they do not touch the metal walls.
Older houses may not have ground wires in the cables going to the electrical outlets. You may see that the outlets do not have the third ground prong, but some may have the neutral wire connected to both the neutral prong and the ground prong, or the ground prong is simply not connected to anything.
Having proper ground available on all outlets helps lowering the electrical fields around appliances, such as refrigerators and washing machines.
Some American houses that were wired before the 1950s may have “knob and tube wiring” where the hot and neutral wires were run widely apart. This type of wiring produces high magnetic and electric fields, and should be fully replaced. There are not many houses with this any longer.
Apartments are difficult because the neighbors are so close. Shared walls, ceilings and floors usually contain wires controlled by the neighbors. Dirty electricity (high frequency transients) can easily travel between the apartments on the phase, neutral and ground wires. The neutral and ground wires can be several volts above the actual ground potential because the wires tend to go longer distances from the ground rod. Larger buildings also tend to have more electronics (computers, televisions, etc.) that each dump small amounts of current on the ground wires.
Since you probably do not own the entire building (or even any of it) it is much more difficult to make changes.
It is usually best to choose an apartment as far away from the bank of electrical meters as possible. Both to avoid the meters and the cables carrying electricity to the other apartments.
Use instruments to measure the magnetic and electrical fields from wiring hidden in the walls, ceiling and floor. If the wiring can’t be modified, consider using galvanized steel plates to cover the radiant surfaces. Steel will dampen both the RF, electrical and magnetic fields (aluminum and copper will not).
It may help to turn off the breakers to the bedroom at night. A landlord may be willing to let an electrician install an automatic switch in the breaker box. A kill switch (that disconnects both wires) is better, but also a more involved installation.
It is unlikely that the landlord will pay for any modifications to the apartment, and what you cannot take with you when you move out becomes the property of the landlord.
More advanced measures
There are more advanced methods that can be used to further reduce the EMF in some cases.
An isolation transformer may reduce the amount of electricity running in the soil under the house, but it is costly to install and wastes electricity.
Filters can be installed to dampen dirty electricity coming into the house on the electric wires from the outside. There are some low-cost plug-in filters available that may help, but it is limited what they can accomplish. In some cases they make things worse. More effective filters must be installed by an electrician and can be costly (especially for the American 120 volt systems as the current is higher).
DC (Direct Current) electricity can be used in a house instead of regular AC (Alternating Current). In praxis this will work well only with a well-designed solar system (not with a 12-volt battery charger or a converter, as they produce lots of “dirty DC”).
Such exotic measures are rarely needed and require detailed information to install correctly. They are not covered in this article. DC solar systems are extensively covered elsewhere on this website (see below).
Check the work
Mistakes happen even for conscientious electricians, and some of this may be new to whomever does the work.
Your local hardware store should have a handy little outlet tester for about $5. Simply plug it into every single electrical outlet in the whole house. It comes with instructions and is very easy to use, just watch the indicator lights to verify each outlet is wired correctly.
It checks to see if the wires have been swapped, if any wire is missing or the ground does not work. It will not detect if there are any unbalanced circuits, dirty electricity, or the ground and neutral wires have been swapped.
Get a gaussmeter (teslameter) and measure around the house with all the breakers off. Then turn all the breakers on, but make sure all lights and appliances are fully unplugged. You should get similar readings with the meter whether the breakers are all on or all off.
Then turn on various lights and appliances, and measure around the house again. You’ll probably get higher readings near the appliances, but further away the levels should be close to what they were with the breakers off.
If there are any problems, try turning off all the breakers, except one. Then measure again. Turn on a second breaker and measure again. You should be able to identify which circuit is causing the higher reading. There may be multiple circuits with problems. There may be more than one problem on the same circuit. Troubleshooting can be difficult.
Hiring people to do the work
A competent and open-minded electrician should be able to do this work. Working with metal conduit is something any electrician should be familiar with, since it is standard practice for commercial buildings in the United States and other places.
Print out a copy of this article and give it to the electrician you are considering hiring for the job, then see if he is comfortable with it all. A good electrician can also provide helpful information during the planning.
There are electricians who are slobs or unwilling to learn something new, even though they are great at talking up their skills. Remember, they all have to sell themselves or they won’t get any work.
Since parts of the work are a little different than what they are used to, electricians may be reluctant to provide a firm bid on the job. Or their bid may be higher than reasonable, to be sure they are covered. It may be cheaper to hire on a time and materials basis instead.
We highly recommend the book Tracing EMFs in Building Wiring and Grounding, by Karl Riley for detailed information about unbalanced circuits, stray electricity and how to track down problems in existing wiring.