How to protect from EMFs, EFs, RFs in a Van

Rivka

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I just bought a 2017 Toyota Hiace campervan van and will be driving it for a considerable amount of time every day. I tested it with an EMF-380 reader when the engine was on and the EMFs are over 300mG on the seats (same as in an aeroplane! The problem with these vans is that you are sitting on the engine/alternator itself. Does anyone have any tips on how to shield the cabin and seating area for EMF protection? Any materials you would recommend and any other tips? TIA
 

DrJ

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You have to ground the metal between you and the source of the emf. If there is still induced fields then you need "magnetic" shielding.
 

Marcine

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You might want to wear that silver thread underwear/tshirt. Those covers they put on smart meters would be a good thing to research and have one fabricated?
 

FredSonoma

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You have to ground the metal between you and the source of the emf. If there is still induced fields then you need "magnetic" shielding.
I don't think you could ground a vehicle

Also it is possible but not easy to shield magnetic fields, there is a specific metal you need. You can't shield as easily as radio waves, which are blocked by any metal
 

DrJ

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I don't think you could ground a vehicle

Also it is possible but not easy to shield magnetic fields, there is a specific metal you need. You can't shield as easily as radio waves, which are blocked by any metal
Well 'ground' is always relative and indeed most cars are grounded through the tires since the modern ones are conductive to avoid static charge build up. If he/she is camping they could consider sinking a ground rod connected to the can frame for a better ground while stationary.

It is pretty easy to shield magnetic fields with 'mu metal' of which stainless steel is readily available and quite inexpensive in a mesh or foil form (plus light to preserve gas mileage).
 

FredSonoma

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Well 'ground' is always relative and indeed most cars are grounded through the tires since the modern ones are conductive to avoid static charge build up. If he/she is camping they could consider sinking a ground rod connected to the can frame for a better ground while stationary.

It is pretty easy to shield magnetic fields with 'mu metal' of which stainless steel is readily available and quite inexpensive in a mesh or foil form (plus light to preserve gas mileage).
Ah okay, I think his issue is when the vehicle is on. Is there any way to ground stray voltage while the vehicle is moving?
 

DrJ

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Ah okay, I think his issue is when the vehicle is on. Is there any way to ground stray voltage while the vehicle is moving?
Yeah you would still ground to the frame presuming the conductive wheels are grounding the frame.
 

FredSonoma

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Yeah you would still ground to the frame presuming the conductive wheels are grounding the frame.
I see okay that's good to know, thank you. Does the shielding have to be grounded for blocking magnetic fields? I often hear that you need to ground shielding for RF, but I've tested it and grounding doesn't make a difference (even Ray has said that it's needed)
 

DrJ

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I see okay that's good to know, thank you. Does the shielding have to be grounded for blocking magnetic fields? I often hear that you need to ground shielding for RF, but I've tested it and grounding doesn't make a difference (even Ray has said that it's needed)
As far as I know the 'magnetic shielding' does not have to be grounded to block the magnetic fields since the magnetic-induction-blocking effect is by virtue of the material makeup, not what potential (voltage) it has been tied to.

Indeed in general you must ground a 'direct' electrical shield for it to prevent direct transmission of an electrical field (but sometimes if the shield is massive enough or depending on its geometry this may not be strictly necessary). However, when a magnetic field (from an alternating current) induces current flow in another conductor inside the shield, which then itself will emit a secondary electric field inside the shield, then it will not matter if the shield is grounded or not. It will matter if the shield is made up of a 'mu metal' that blocks the magnetic field inducing the secondary electrical field. But for example you can use a grounded stainless steel shield to block both phenomena since it provides both the grounded conductor shield as well as the magnetic induction shield (being a mu metal).
 

FredSonoma

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As far as I know the 'magnetic shielding' does not have to be grounded to block the magnetic fields since the magnetic-induction-blocking effect is by virtue of the material makeup, not what potential (voltage) it has been tied to.

Indeed in general you must ground a 'direct' electrical shield for it to prevent direct transmission of an electrical field (but sometimes if the shield is massive enough or depending on its geometry this may not be strictly necessary). However, when a magnetic field (from an alternating current) induces current flow in another conductor inside the shield, which then itself will emit a secondary electric field inside the shield, then it will not matter if the shield is grounded or not. It will matter if the shield is made up of a 'mu metal' that blocks the magnetic field inducing the secondary electrical field. But for example you can use a grounded stainless steel shield to block both phenomena since it provides both the grounded conductor shield as well as the magnetic induction shield (being a mu metal).
Thank you
 

StephanF

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You may also have ‘dirty electricity’ from the alternator and the ignition system. This EMF travels through the wiring throughout the vehicle.

You need to filter the DC coming from the alternator, this is a tricky thing, since ‘ground’ is the car’s chassis. I am not a car mechanics but in most cars, the negative pole is directly connected to the chassis, and the negative lead from the alternator probably, too.

Someone with more insight in the electrical wiring in cars may want to comment here…

Such an EMF filter should be attached as closely as possible to the alternator. An EMF or EMI filter consist of one or more LC circuits, acting as a lowpass filter. Shielding and filtering at the origin of the EMF source is most effective. I am not sure if there are shielded spark plug wires?

Mu metal is mostly used to shield against the magnetic field of the earth, which is (almost) static. A good conductor will shield well against alternating magnetic fields, due to Faraday induction.

I used mu metal to shield against earth’s magnetic fields in my Ph.D. experimental setup, where I used an electron gun. I used braided copper shielding to shield against pulsed EMF from a terawatt pulser in plasma physics experiments. We also needed single point grounding to avoid ground loops. This is a science of its own…

 
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