Electromagnetic Field Shielding ?

Electromagnetic Field Shielding ?


I wanted to ask if anyone had a chance to measure the EMF in the Model S front and back, or if anyone has information about the measures Tesla took to protect the passengers and driver from EMF.


Teoatawki | September 16, 2012

I guess we were about due to go down this alley again


mrspaghetti | September 17, 2012

Not worth worrying about, in my opinion. Everything has some kind of hazards associated with it, including getting out of bed. The biggest hazard you will face driving your Model S is the same one you face driving any other car - other drivers.

Embrace the fact that you're going to die some day and enjoy life while it lasts.

Brian H | September 17, 2012

Your headset/earbuds and connector wire produce vastly more EMF exposure.

ybachar | September 17, 2012

This is not correct about the earbuds or headsets and one major difference is that I use my headset for 10 minutes a day and drive me car for hours a day.
The size of the electric motor on the back of the Tesla model is is very large and for sure produces high electromagnetic field around it. I assume Tesla took the measures for shielding it but I was looking for a more professional measured numbers reply. If someone has the numbers.
Also the rear seat in the Tesla will be used by kids which are much more sensitive to the effects of EMF and do not have the above exposures you refer to from cell phone use.
Tesla team, do you have measured numbers you can share?

olanmills | September 17, 2012

"This is not correct about the earbuds or headsets and one major difference is that I use my headset for 10 minutes a day and drive me car for hours a day."

Haha, I would have expected it to be the reverse or at least closer to even for many people.

I don't care about EMF. I'll bathe in it. It gives me super powers!

If you're concerned, then I think maybe you should move to the moon.

ParkCityKen | September 17, 2012

I'm not worried about EMF, but has anyone considered the impact of a 25' coil of wire with 80 amps being fully electrified while the car is charging? I'm thinking here about a magnetic field being set up around the coil.

With 25' of cable on the HPWC, but with it mounted 3' from the charging port, there is a lot of excess cable.

Nothing to worry about is there?

jerry3 | September 17, 2012


No, there's nothing to worry about. You might as well worry about your house wiring or your electric stove. Let's put it this way: If you smoke, you don't need to worry about any other health issues. If you don't then weight and/or alcohol are what you should worry about. EMF is about number 10,000 on the list. Millions of people have sat for years in front of CRT screens with no ill effects. | September 17, 2012

Maybe if we line them up properly we could generate 5 Tesla images? (MRI joke folks :o)

ParkCityKen | September 17, 2012

I wasn't really worried about health, but the magnet attracting metal objects. But I guess not ...

ybachar | September 17, 2012

If someone has a real valid professional answer please reply. We can skip all the guessing answers.

Thank you.

KeithE | September 17, 2012

While I have read many older tesla blogs on the topic and am comfortable there should not be an emf issue my wife is very concerned what the emf readings in the Model S will be like during charging. This is important to us since our garage is directly below our 7 yer old sons bedroom. Wold greatly appreciate if customers or tesla could provide accurate data on is this during charging before I confirm/ finalize my order Thanks!

EdG | September 17, 2012

When the "valid professional" tells you the actual numerical value of the electromagnetic fields how will you react? Will you insist it should be zero, unlike every grid-connected building in the world? Will you forever worry about it while you drive the car?

How can you travel down a street or highway behind cars and trucks that are designed so the owners leave the stinky gases behind them for others to breathe in? If that were safe, why isn't the "tailpipe" shortened to save money?

The most dangerous thing about driving the Model S is getting into an accident while going at high speed. While the car is designed to minimize that danger, it is quite real and (statistically) measurable.

Fear of EMF is not measurable, and hazards of EMF exposure at less than microwave frequencies have yet to be shown at all, and exist only in the minds of the imaginative.

Microwaves can burn tissue. Ultraviolet radiation can cause skin cancers. XRays and other high energy particles (the higher the frequency, the higher the energy) can cause cancer.

Perhaps the CDC hasn't issued a warning about house wiring because of a conspiracy? Ooooohh...

Relax. Enjoy life. Stop worrying about nothing. If you want to worry, make it about real things. There are plenty of people dying of famine, war, disease, etc. Worry about that.

As for EMF fields during charging, they're the same type as those emitted during use of any electrical appliance. If the current is high, the EMF is high. But if you double the distance from it, you lose 3/4 of the field strength. So if your charging cabling is ten feet from your son and the current is ten times that of the light one foot away from him, then the car charging is giving one tenth the field that the light is. (1/10 * 1/10 * 10) If you're not worried about house lighting and other "plugged in things", don't worry about the car or its charging.

ltd | September 17, 2012

Tesla has in the past advertised for EMI/EMR specialists and there are numerous patents applied for and some granted to Tesla Motors.

Issued patent US8242739 indicates that the AC motor does have some EMI filters in at least one AC motor design.

You may be able to give someone a call at Telsa and have a chat with them. There's a variety of folks' names listed on the designs, I'm sure that in some form they'd be able to talk about their testing.

Brian H | September 17, 2012

Turn off the monitor on which you are reading this, now! It is zapping you up close with more EMF than Tesla charger at full load.

Some people need to relocate to 1700, stat. Life expectancy, about 43.

mrspaghetti | September 17, 2012

As an engineer and former nuclear power plant operator specializing in radiological controls I am confident there is nothing to worry about with emf from the model s.

That being said, the car is so awesome I might still buy it even if someone demonstrated that there was a chance my testicles would shrivel up and fall off from driving it.

EdG | September 17, 2012 +1. Funny.

Note that the EMI filters they put on the motor was strictly to stop any radiation from interfering with other equipment as per FCC rules. Otherwise you might "hear" the motor when the radio was on, or it might disturb cellular communication or WiFi.

The filters were not put in to reduce the EMF going through people. As an engineer, I've worked on projects that had to put on similar EMI (ElectroMagnetic Interference) filters.

Bennett R. | September 17, 2012

I've read threads on a lot of different subjects on this forum, and I must say, it is striking how different the tone of the responses is on this one than on any other one. It's a perfectly legitimate question, but it seems that people are more concerned about setting their own minds at ease by ridiculing it.

If you don't know the answer or don't care about the issue, then why don't you just go elsewhere on the forum or keep quiet?

I can rebut many of the ridiculous responses that are being given, but it's not worth it.

olanmills | September 17, 2012

It's not really a legitimate question. I suppose there's nothing wrong with being curious if you really don't know, but we should not give the impression that there's some sort of serious medical/scientific debate going on.

There is no credible evidence that the kind of EM people are subjected to every day is harmful (bullet trains, power tools, power lines, elevators, cars, cell phones, and on and on)

EM fields and electromagnetic radiation (which includes radio, X-ray, etc) are not the same type of thing.

The "concerns" that have come up are from people trying to claim living underneath powerlines has caused them some harm, same as people trying to scare you about flouride or vaccinations.

These "concerns" have been around for a long time (after all, large EM fields have been around for decades), and it has been studied.

To carry on as if there is a debate about the affects would be disingenuous.

walla2 | September 17, 2012

It must be lower than even a low 0.3 Tesla MRI because otherwise they would've had to have pacemaker warnings on the Roadster and the S.

Not saying its nothing, but I suspect it gives off less EMF than an iPad.

Bennett R. | September 17, 2012

re: olanmills

Your response is qualitatively different than many of the others that were given, both in tone and substance. It's a legitimate response, without ridiculing the question.

However, while it may be true that no health effects from EMF have been proven, I believe the converse is also true. It has not been proven that there are not any long term health effects from prolonged exposure. Also, riding on top of a powerful battery in an enclosed area is a bit different than being 30 feet below power wires in an open area.

I'm not saying there is an adverse health impact; I'm saying the jury is still out. For me personally, I don't intend to let it stop me from buying my Model S.

Brian H | September 17, 2012

Hard to prove a negative like that. Prove you are not the Queen of the Space Unicorns in disguise!

pilotSteve | September 17, 2012

Remember that electromagnetic radiation drops with the square of the distance from the source. So the passenger compartment (front especially but also back seats) are located many inches (if not many feet) away from the motor and motor controller. I expect that there will be a very low (comparable to background magnetic fields in your living room).

In any event, I (really) do have an industrial gauss meter and will post some readings after my Sig arrives.

Note to Tesla: you really should push my car to the front of the queue so I can make these readings post haste!

Bennett R. | September 17, 2012

Re: Brian H.

My point is that it is an area that is under active investigation currently. It is actually possible to prove a negative. It's not the same as, for example, trying to prove that you never did or never said something.

Anyway, I'm signing off. I'vr had enough of this topic.


Brian H | September 17, 2012

The wording of the negative(s) can be tweaked indefinitely, requiring impossible numbers of "samples" and measurements. Calculations show there is little or no EMF for the passengers. Prove that there is.

Robert22 | September 17, 2012


As much as everyone would like to ignore this question, it is most certainly relevant from a cell biology perspective. You'll notice from one of the threads above (or another) that I got beat up pretty badly when discussing it several months ago. This board is probably not the proper forum for an in depth discussion of this topic. To be clear, this is not a criticism of Tesla or the car, but intelligent humans need to be aware that the final word on EMF safety is most certainly not in. There is no debate that EMF can and does affect cellular function. The question is whether the effect is pathophysiologic. I discussed this issue with a Tesla engineer two years ago and I can tell you that occupant EMF exposure was definitely a consideration that factored into the final design of the car (to Tesla's credit). There is ongoing investigation into the effects of low and high level EMF on biological systems. You will hear more about this topic as the peer-reviewed data becomes available. Smoking and low level ionizing radiation seemed pretty harmless in the fifties. Keep an open mind.

+1 Bennett R- More to learn in other topics at this time.

jbunn | September 17, 2012

I'm going with the null hypothesis until i see evidence to the contrary.

I'm not too worried about the DC battery. If anything,I'd be concerned with the PEM that produces variable frequency AC.

I've probably got a few hundred yards of 120 and 240 VAC running through my walls and ceilings, and DC resistive heating in the two upstairs floors, and 120 AC resistive heating in the basement.

Come to think of it, I've probably got a lot more wire than I thought.

Besides, once I got used to the idea of growing a second head, I found it quite usefull as he scans this blog when I'm sleeping. I miss the family jewels, but my breeding days were over, and besides, they probably needed to go. The doctor seemed rather frightned.

Timo | September 17, 2012

@ken I wasn't really worried about health, but the magnet attracting metal objects.

Magnetic fields weaken fast with distance, you can hardly measure it outside of the car at all. Also aluminum resists magnetic fields, so that works as natural shield. Also it is three-phase rotating field, each phase combined would be zero field, so at the outside of the motor there is practically no field at all. Definitely nothing that affects human tissues, except by nutjobs imagination-caused placebo-effect. Fumes from gasoline engines would be about gazillion times more dangerous. Mildly speaking.

Brian H | September 18, 2012

There is no magnet in the TM motor. The magnetic fields are generated "on demand" by current in the coils. No permanent magnet, no rare earths, etc. Most advanced on the planet, AFAICT.

Timo | September 18, 2012

BTW, how doesn't it concern these people that ICE cars have exactly same things. They have generator which is basically a electric motor in reverse, coil to increase battery 12V to kilovolt-area, spark plugs that cause a very strong pulsing EMF. Car stereo system loudspeakers are much closer to passengers than electric motor in BEV and those have variable frequency magnetic fields. All the fans into cabine that blow air in it have small electric motors.

etc. etc. etc.

mrspaghetti | September 18, 2012

Those of you who have been driving Roadsters all these years, I'm afraid I have some bad news - you're going to die someday. It might not be from your emf exposure, but if not it will be from something else.

Brian H | September 18, 2012

Protect yourself by extending the aluminum foil beret down to about ankle level.

mrspaghetti | September 18, 2012

Does the Model S come with one of those?! Cool!!

BrianH +1 - too funny

EdG | September 18, 2012

Don't forget to attach it to ground.

Electric Machete | September 18, 2012

I'm entertained by this conversation to say the least. I'm an ER doctor and I get questions from patients all of the time about the amount of radiation exposure in CT scans and plain x-rays. Radiation can cause DNA mutation which can lead to cancer and other badness.

I have never heard any concern regarding MRI, which has a gigantic EMF. I can understand how EMF can affect cellular biology, but I can't really imagine how that could translate into that could cause permanent harm. I am open to idea that it could, but I don't even know what kind of effects people are concerned about.

There really isn't anything in the medical literature to suggest harm from EMF. What are the concerns, specifically, that some of you have? Cancer? Dementia? Infertility? I'm just curious and would like to learn more.

Sudre_ | September 18, 2012

I've been trying to not post to this thread because I think the question is... well silly is a nice way to put it, not because EMF is bad for a person, I have no clue to be honest. It's more about knowing what the risks are in comparison to the alternatives.

A friend of mine has concerns over EMF. She refuses to use compact florescent light bulbs because of the EMF they put out. I asked her what the EMF was of an indecent light bulb and she had no idea, "BUT IT MUST BE LESS!" was her only answer.

I have an electric dryer. How far away should I stand from it?
My electric furnace? Should I just stay cold in winter or is the risk less than a gas furnace exploding or killing me with CO? Worst yet I have an insta-heat electric hot water heater. It's surge current is 100 amps for a few minutes while it gets the water up to temp then drops to 20 to 40 depending on incoming water temp.... maybe I should stand a couple hundred feet away while it is on?

I've got the perfect solution. Lets shut down all the power plants and go back to burning wood, coal and candles. I am sure that those items are less toxic than EMF... right?

David Trushin | September 18, 2012

I have a different concern about emf for this car. Many traffic lights use inductive loops to determine the presence of a car so they can change to green for the car. Does the model S have a strong enough magnetic field to cause these lights to change?

jerry3 | September 18, 2012


It doesn't take much. If you ride a bicycle you have to lay the bicycle down for a second to trigger the lights, so that should give you an idea.

ybachar | September 18, 2012

Thank you for people that responded respectfully and nicely.

For the rest of you, GET A LIFE....

EdG | September 18, 2012

@ybachar: I'm curious: did any of these replies change your mind about EMR? Was there anything learned here? Are things more or less confused or different in any way?

jbunn | September 18, 2012

David, an aluminum car has more than enough conductive metal to be an inductor, even though aluminum is not a permanent magnet. Induction causes it to generate a magnetic field.

Brian H | September 19, 2012

Lots of steel in the crash-proofing framework in the S, I believe.

Timo | September 19, 2012

@Electric Machete, I have had a small encounter with EMF nutjob. She claimed that she gets nausea etc. whenever there was a wireless access point nearby. Funny thing was that while she was complaining this to me she was standing practically right underneath one of those and didn't have any symptoms at all. She just didn't know that there was one.

[general ranting]
I believe that EMF nutjobs are same class as homeopathy nutjobs, if there is any effect at all it is placebo-effect. Those nutjobs probably have no idea what "EMF" actually is.

As for long term effects, they probably claim any health issue as "result of EMF or EMR exposure". Fact is that if there is any effect at all (from systems like electric motors) it will be a lot less than what microparticle and toxic fume exposure from gasoline and diesel engines is. This can be taken as a fact just because we haven't seen any effect at all, and if there were any it would have been noticed by now.[/general ranting]

Vawlkus | September 19, 2012

As someone who works on transmitters rated for kilowatts for military applications, I feel perfectly justified in calling people worrying about emf or emr being generated from a Tesla vehicle completely nuts (if I'm going to be polite about it).

jkirkebo | September 19, 2012

Yeah, funny how some people will be concerned about things like EMF exposure, which have no scientific basis at all, then completely disregard all scientific evidence pointing to global warming from CO2...

jerry3 | September 19, 2012



Brian H | September 19, 2012


And many more. Every prediction of temp response to CO2 increase has failed. (The connection runs the opposite direction.) If so much money weren't riding on it, the hypothesis would have been deep-sixed years ago.

Sudre_ | September 19, 2012

Brian H are you standing by a strong EMF? LOL

pilotSteve | September 19, 2012

@jkrikego - oh man, you went and popped BrianH off again!

@BrianH - Please don't rehash this yet again. EMI is a different concern (perhaps unwarranted but some wish to write about it) so lets not conflate global warming and EMI. Puuuuulease!

Brian H | September 19, 2012

Please check who opened the subject.

Also do yourself a favour and read the links. | September 19, 2012

Well folks, just to muddy the waters a little-- MRIs are now being studied for treatment of intractable depression--with some promising results that do not appear attributable to placebo effect. Intense magnetic fields in the temporal lobe appear to affect moods-- that being said the "Tesla Smile" on my test drive had nothing to do with EMF and everything to do with handling/acceleration.