Slashdot Mirror
Electrical Shielding for the Homeowner?
AugstWest asks: "As more research comes out showing that high voltage electricity sources can cause cancer and other health problems, I was wondering what the geeks among us could come up with for electrical shielding ideas. I've got a high-voltage transformer just off my backyard to power the train that also runs practically through my backyard, and it would be nice if I could somehow shield us from it. Of course, if the shield could also be an induction coil to sap power for my house, that wouldn't suck either..."
And not peanut butter, either. Lead!!
Show this to your friends and family that don't know what a real hacker is
As more research comes out showing that high voltage electricity sources can cause cancer and other health problems.
Okay I RTFA because I thought this had been effectively pooh-poohed and was interested in seeing additional research. But TFA is from 1996!!?? and the poster has the audacity to claim this as more research!!?? Cliff, what were you smoking in you posted this? The other FA is concerned about breathing ions. Oh my gosh, I salted my beans at lunch and ingested ions!!
This is really a new low for slashdot.
Easy, build one of these.
Of course, you could also cover your body with aluminium foil, that way, you'll be protected when you leave your house too!
Tin foil hat...
And survey your living spaces. When my daughter was a couple years old and the powerline/childhood leukemia thing hit the news, I did just that. I relocated the main feeder cable from my meter to my breaker box to get the field down to zero in her room. I was able to do it by just pulling some giant staples out of the cable and moving it without disturbing connections. YMMV, hire an electrician for anything more invasive.
As to the stuff not on your property, I'll bet that it's still undetectable thanks to the inverse square law.
In any case, if it's bothering you, the first thing to do is rent the meter and do a survey.
"Eve of Destruction", it's not just for old hippies anymore...
Cliff, I've often thought that you are one of the best Slashdot editors. But this article should not have appeared on Slashdot.
Slashdot often carries pseudo-science articles, especially recently. Slashdot editors need to be more careful about that. If you didn't listen in Physics class in college, talk to someone who did.
Personally, I believe that there are a lot more things a lot more ruinous to your health than a couple of humming wires stung out in your backyard. However, saying that, we'll move on.
Ok, so you have a power line to supply trains running along the back of your house. Exactly how hot is it? 25kV? 66kV? Check the insulators - anything longer than a foot (or so) is high voltage, anything less is likely 3.3kV or below.
If you don't have a field strengh meter, get an average 36W fluoro, go out to your backyard barefoot at night and hold one end. Wave it around a bit - if there's any serious amount of power around, it will light up the closer you get to the lines. Check how much it drops off between the back of your backyard and your house.
Field strength drops off with the square of distance, so unless you're directly under 300kV lines, you probably have more pressing things to worry about, like that clock radio near your head when you sleep. Or the electric blanket that's millimeters away from you. Or the colour TV (or monitor) that is basically a particle accelerator.
If the wires are an appreciable height above your roofline, and you are still concerned, earth out your roof (properly, with a ground stake,etc). This will shield the bulk of your house. Personally, as mentioned before, I'd go worry about other things, such as the resistant bacteria thats cropping up, or the apparent dwindling oil supply, or whether N. Korea gets The Bomb.
You are in a twisty maze of processor lines, all alike.
There is a lot of hype here.
I just read John Stossel's [liberals-are-cringing] book "Give Me A Break!" and it has some actual facts concerning personal risks, something quite lacking in the media, and that also appears to be a problem the poster and editor appear to have. So here, off the top of my head, are just a few of many suggestions, any one of which will have a well-documented, much better chance of both improving one's health and lengthening one's life:
1. Fasten seat belts always when in a moving car.
2. Don't drive under the influence of alcohol or mind-altering drugs.
3. Quit smoking
4. Stay upwind of smokers
5. Eat less fat and less meat, eat more fruits and veggies, especially raw ones.
6. Do some aerobic exercise (swim/bike/run/jog/walk/skate) several times per week.
7. Trade the VW Beetle (or other bad-in-a-crash car) for a Volvo (or other good-safety-record-for-its-driver vehicle).
8. Don't drive when drunk/drugged drivers are most likely to be driving.
Okay, I'm sure there are 492 other things that many people commonly do that have a proven, more detrimental effect on life and health ELF fields/living next to high-voltage power lines that people were so worried about in the 1980's and 1990's (the real danger to living near such lines is if one falls and hits the ground - you could be electrocuted by walking away from it! Hop (keep your feet together!) away, don't walk). Even if it's "scientifically proven" (or even a very strong statistical correlation shown) that cancer rates are higher near 60Hz high voltage (electrostatic fields) or high current (generating strong magnetic fields) lines, there are so many other things that we KNOW are MORE risky that any cost-benefit analysis would dictate that it's better to spend thousands of times more money on these other things before you even LOOK at whether ELF radiation kills 0.0001 person per million per year, or if it's even as much as 0.01 person per million per year.
Slashdot's new look looks serious. And especially with responses like this (ELF is NOT news, and it's NOT Stuff That Matters), I'll have to come up with a more serious tagline.
Tag lost or not installed.
1. Don't use electricity, period. Especially all that nasty AC that runs throw all the walls in your house.
2. Either deep underground or live in a Faraday cage (this may be tought without electricity).
7. Trade the VW Beetle (or other bad-in-a-crash car) for a Volvo (or other good-safety-record-for-its-driver vehicle).
/.
Ok, where exactly did you here that the Beetle is bad in a crash? Since when is Four stars considered "bad"?
And let's not forget that (1) crash avoidance is more important than trying to be a "bubble", and if we're going to toss around marketroid allegations as truth I'd rather a distinctive (i.e., visible) beetle over a "safe" volvo, or (2) the more important measure of a "by the numbers" car is (fuel and non-fuel) economy, and both cars have a fair bit of credibility in that status. (To say nothing of the rather significant non-fuel economies you get with a slightly used or american-made car.)
Anyway...
This is the Ask Slashdot section. It's where someone asks a question, and they get an answer. In fact, this is a great question for Ask Slashdot, because there were already two great responses ("build a faraday cage" and "get a meter to test") already. It's the equivalent of a "letters to the editor" page, if you really want to stretch a newspaper paradigm to fit
(And I'd change your "eat less meat / more vegetables" to a much more intelligent "see your doctor, ask him for diet advice, and follow it" line. Eating no meat and nothing but raw vegtebles is bad for you in entirely different ways than the inverse, but it's still bad for you.)
Of course, if the shield could also be an induction coil to sap power for my house, that wouldn't suck either..."
1) That is theft. Even induced current isn't free.
2) I believe the coil would have to be placed pystically around the transformer, and the train company would be bound to notice that at some point. See #1.
Hmm, I wonder why this person is worrying about high voltage particularly? I mean, 60 Hz EM fields saturate his house already because of the electricity running all through the walls and ceilings. The fields are exactly the same frequency, photon energy, et cetera.
Now, a 6000-volt (say) transformer has a field strength right next to it about 60 times higher than the field strength right next to a wall socket. But, thanks to the inverse square law, the field strength 10 feet away from such a transformer would be less than the field strength 1 foot away from a wall socket.
And...he probably spends hours and hours within 1 foot of a wall socket, and isn't likely to be within 10 feet of the transformer very often at all...I mean, unless the transformer fascinates him strangely or something...
This book contains all the info you need for this project.
The XFO is a _good_ sign. They can't leak much and already have a Faraday cage around them. Best of all, an XFO is usually in the middle of a section, far away from those spark-inducing section isolation breaks. They create all kinds of nasty noise and ozone.
7. Trade the VW Beetle (or other bad-in-a-crash car) for a Volvo (or other good-safety-record-for-its-driver vehicle).
Ok, where exactly did you here that the Beetle is bad in a crash? Since when is Four stars considered "bad"?
If I remember the specific 20/20 it was back before the new Beetle came out, years ago. So he is saying the old VW Beetle, the one with the air cooled engine in the rear.
> "Use the product of mass and the integral of jerk, Luke."
Use the force plus mass times a constant? Looks like someone didn't quite pass calculus.
My other car is first.
I wear a Tin Foil Hat to protect /me from the negative health effects of "high voltage electricity sources". As I side benefit no one can hear the voices in my head but me, and the government has stopped controlling my every move!
"This mission is too important to allow you to jeopardize it." -- HAL
If you have large transformer close to home, you may need magnetic shielding, not electric one. First, try to estimate strength of magnetic field. Use simple open induction coil and multimeter for this. If you will find rather strong magnetic field, change your house or destroy transformer, because good magnetic shield for 60 Hz is difficult to create.
Transformers, transmission lines, GSM base stations and radio/TV transmitters are very important things to check when you are looking for new home.
I have 4 or 5 high-voltage transmission lines in 100-200m from our building. But this is not a big problem because reinforcement of walls acts as electric shield.
Stealing by induction is illegal, obviously, and can be detected by the power company/owner easily and exactly. Basically any loop that is passed through an electic field will create induction, which wouldnt interfere with the electric field anyway. I know an electrician that has gotten cancer playing catch the electricity, but, unless you are talking a REALLY strong electric field, and very close proximity, do what everyone else says and worry about the mold in the walls or the rampaging duck.
Rather than trying to shield an entire house, just build yourself a set of Orgone accumulators for every member of the family and spend as much time in them as possible.
The thin metal walls are sure to do as good a job attenuating 60 Hz EMF as they do re-radiating orgone energy.
You also might want to consider placing them in the left hand middle section of you home and painting them green so as to get as much Feng Shui benefit as you can while you're at it.
Seriously, there are a lot of very real environmental hazards to worry about, but this isn't one of them. So far, decades of research have turned up no reliable evidence for risk associated with low level, low frequency electromagnetic fields, and no one can come up with an even slightly plausible mechanism by which they could damage the body.
By all means, worry about what you're breathing, and the chemicals in your food and water. (And if you want to worry about things which are orders of magnitude more likely to do you in, consider how you get to work, your diet, and exercise regimen.) Don't worry about environmental EMF exposure.
I suggest you start with the World Health Organisation.
... doesn't mean something is good to ingest. There actually may be some truth behind the touted dangers of fluoridated water, aside from the whole matter of actually drinking something that really should only stay on your teeth for a while before being spat out.
A google for "fluoridation sewage" or "fluoridation sludge" will give you an interesting look on where cities get the raw material to add fluoride to water, and it's not very appetizing, especially considering the trace amounts of heavy metals and other rather toxic materials that just aren't feasible to remove from the "product". Then consider the possibility of skeletal fluorsis, which occurs when too much fluorine is ingested, which is where the skeletal bones basically rot/disintegrate.
Vaccination isn't without its dangers, although for the most serious viruses, polio, etc., the vaccination risk seems more than made up for. Refined sugar isn't a wise thing to stuff into your body, either. Maybe the guy is going overboard (haven't read about him, specifically), but there is certainly a grain of truth behind all that "whacky quackery".
Since when did "eat less meat / more vegetables" become "eating no meat and nothing but raw vegetables"?
Do you like to take everything to its most extreme conclusion? Honestly, there is nothing within that sentence that on its own supplied the implication of going "all the way." You took that one and ran with it on your own. People can start to control their eating habits and get benefits without consulting a doctor. And by the way, "control" does not mean "eliminate all of one substance."
As others have pointed out, this risk is massively overblown. That said, if you're truly paranoid, here you go: LessEMF.com They've got a complete line of electric shielding clothes, canopies, etc.: Personal EMF Shielding Devices They also have mu-metal cloth for making your own magnetic shield clothing.
People can start to control their eating habits and get benefits without consulting a doctor.
Not the sort of people who need to be told to control their eating habits, though. The same reactionary mind that looks at power lines too far away to detect without eyes or a camera as a threat will take an advice to "eat less meat and more vegetables" as a reason to toss their (and their family's) perfectly healthy balanced diet and become never-cooking vegans.
You're right, though. There are other folk who can advise you on making a healthy diet. The FDA is probably a good place to start, and absent them a licensed dietician or even a grocer or high school health teacher.
Make hats for your entire family (don't forget the pets!). It has to be real tinfoil, though. Aluminum won't do.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
And replace with lead lined drywall, used for sheilding from Xrays and others.
See http://www.radiationproducts.com/gypsum-board.htm for example, and other
similar products.
You may notice some problems with things like cell phone reception afterwards.
There are positive and negative electric charges, but only one kind of gravity "charge". This makes it possible to block EMF using a faraday cage, but impossible to block gravity.
It also makes electromagnetic and gravitational fields completely incomparable, dimwit.
Find either a physics or radio guy and ask them to explain about the inverse square law. Unless the transformer is underneath your house you need not worry.
Ed Almos
The more corrupt the state, the more numerous the laws. - Tacitus, 56-120 A.D.
That said, I suppose it would be possible to build a structure of laminated hi mu silicon steel around a residential dwelling providing both magnetic and electrostatic shielding so long as no windows were provided, the door(s) fabricated to minimize leakage, and special measures were taken at entry points for air and so forth.
EM field strength within such an enclosure would be effectively zero so long as all electrical devices of any sort (120/240V line supplies, phone lines, battery operated devices, etc.) remained outside the building.
Not much of a home. Cheaper to build a cabin in a deep wilderness setting, and become a pre-1900's farmer/hunter/gather.
I've got a high-voltage transformer just off my backyard to power the train that also runs practically through my backyard
J F'n C, man... move!
7. Trade the VW Beetle (or other bad-in-a-crash car) for a Volvo (or other good-safety-record-for-its-driver vehicle).
Not so long ago, Volvo sales manager for Russia was killed by lightning in the middle of his backswing while playing golf near Karlstejn castle (Czech republic, Europe). Playing golf while storm is coming shall be also on your list.
I'm not insane. My mother had me tested.
You write "Just like in the US it is illegal to tap signals that you normally have to pay for, such as satellite TV"
Uh, no. There are supreme court decisions that say you can do this.
There are no karma whores, only moderation johns
There is a substation a few miles from my house that can light up a plain ordinary compact florrie if you stand within 5' of the surrounding fence.
Why shield the whole house? bricks and morter are not effected but EM; Instead wear cloathing made with a wire mess sown in and a the ubiquitus foil hat, that way you can take it with you.
In the not too distant future, next Sunday A.D.
High-voltage stuff does have significant fields - though any effect on humans is far, far from proven. The flourescent light trick is cool (and scary to some), but means little. The whole worries over power lines seemed to spring originally from the reporting over Love Canal. Most people don't understand electricity, and the idea of an unseen field flowing through their body is unnerving to them (irregardless of the facts).
Most of the studies of power-lines have trouble accounting for the fact that housing prices right next to HV powerlines are noticably lower - originally mostly for esthetic and sound reasons, now also due to fear of the unknown. In addition to causing different demographics of buyers, there are other related issues. For example, when planning powerlines, they don't just draw a line across a map - they try to minimize the cost of buying the land. Guess what? Brownfields are cheaper, and industrial area have less people objecting than "virgin" suburban land. And once the lines are in, businesses are more likely to be willing to set up shop under/near HV power lines - esthetics isn't as important to them, price is. Businesses (especially in already-low-value areas) tend to be the ones most likely to release toxins (you don't often see that in farmland). Untangling all this is really tough.
This causes a difference in demographics that's hard to account for. And even so, the demographics don't scream "cause".
More to the point, the original commentor was correct - this question is at best misleading and at worst promotes yet more bad science thinking by assuming facts not in evidence. I wonder how many readers won't notice TFA is from 1996, or won't even read it and assume the poster is correct about "increasing evidence".
Ok, so you have a big transformer near your backyard. Why should you consider it a problem ? Aside from the fact that "big" is a relative term (for train power it cannot be that big, since these are most likely in the 6-12 kV range, certainly not as one found attached to a EE transport backbone), what is of importance here is the fact that the frequency of the electric and magnetic fields is 50 Hz (oops, forgot you are in the USA, make that 60 Hz) and its 3rd and 5th armonics, hence, for you, 180 Hz and 300 Hz, because these are the non-negligible frequencies of the fields you get from a powerline.
Frequency is relevant because with it you have the wavelenght of the field and, in order to decide if the field is dangerous to your health, you have to compare this lenght with the dimension of your cells. Since at 50-60 Hz the wavelength is in the range of thousands of kilometers (and for 300 Hz it's not that much shorter) it's easy to see that you don't have a problem living near one of these things.
This is the exact same reason why cellphones are much more suspicious and why x-rays are confirmed to cause cancers: their frequency (around 10^24 Hz, IIRC) implies the wavelength is much shorter than a cell, making them able to damage it.
The reason this is relevant is because, with long wavelength, the [magnetic | electric] potential at different points in the cell is identical, while with short wavelengths it is not: in this case you have [magnetic | electric] currents that run through your cells (organic tissues are conductive, so you can use the simple model of an impedance), and with current you have heat, inducted currents, parasite currents, etc...
Even for really high voltage lines (i don't know the operative voltages in the USA) there is no issue: in Italy we divide voltages in 3 ranges: 220-380 volt is low voltage, 4.5-23 kV is medium voltage (secondary distribution stations, trains, production plants), and the three high voltages: 130 kV (primary distribution stations), 220 kV and 380 kV (backbones, power plants connections); only for the high voltages, there is a rule of thumb to follow: when you are farther out from the powerline than 5 meters plus 1 centimeter for kV, you are well in the safety area (so for a 380kV line you have to be at least 8.8 meters from the wires; if you are directly under the line, but it's high in the sky, you are clear).
Bye,
Alberto
Good diet and exercise should counter the effects.
The safe one is officially the "New Beetle", not the "Beetle". The "VW Beetle", while only recently discontinued in Mexico, was not a four-star safe car, wheras the "VW New Beetle" is significantly more safe (if not any less horrible to look at).
Lead??? Please, you mean tin!
As in "foil"
--LWM
Not quite, I think. The wires in the wall will function as antennae, with a terrible SWR, to be sure. They will radiate radio waves at 60 Hz, just like this fellow's worrisome transformer does even when the trains aren't running. So there will be a very small current all the time to supply the energy emitted as radio waves.
On the other hand, as you point out, when he fires up (say) his electric range and gets 10 to 20 amps flowing through those coils on top -- look out! Not only does he have strong EMF fields right near his (or the wife's) face, but he's irradiating his food with them.
Hopefully he's got a gas range. (We needn't consider the folly of a microwave, of course.)
I have an electric company transformer exactly two floors under me. It supplies the elecricity for at least our building and one other nearby building (about 30 apartments). A friend of the family that operates a gaussmeter for a living came over and made some measurements around the transformer and in my home and said I had nothing to worry about and the radiation from that transformer is extremely low. When I asked him what does this "low" means practically, he asked if I have some transformer. I plugged in one little 1000mA general purpose transformer I bought at Ace, and the radiation it produced was more than a thousand times more than that produced by the electric company transformer.
So perhaps "cheap" produces more radiation than "powerful"...
Lots and lots of that nice, safe lead should keep you from being poisoned by those nasty power lines! ;-)
You can order stuff from lessemf.com. They have magnetic shielding material too.
I bought some from them to shield an inductor that was sensitive to nearby magnetic fields, but it didn't really help. Now I'm on their mailing list, though, and they have a lot of stuff that sounds like it's right in your market.
What bothers me these days is front-loading washing machines. They have AC variable frequency motors and lots of unshielded computer control components in them, and due to a quirk in the FCC regulations that assumed appliances wouldn't have mostly motors and gears, they are exempt from many of the requirements for Part 15 compliance. My Whirlpool Duet plays havoc with MF, MF, and VHF. I'm going to sell it and get a top-loader with big gears and stuff inside.
Remember that the currents in the power lines are balanced. ie. there is no ground current. That means that the magnetic field due to the current in one line is cancelled by those in the other two (assuming three phase). So, if the lines are separated by five feet and you stand fifty feet away, the field you measure will be negligible.
http://aje.oxfordjournals.org/cgi/content/abstract /161/2/136
Summary -- it's hard to tell.