Must Read: EMF (Electro Magnetic Field) or leaking current/ voltage, and why you need to be aware

[Hedges]

So I'm likely using way less voc (under 145) and watts (under 1200, though possibly inverter will take 2x1200 PV input ...need to check). But it's in a trailer so I have a few concerns:

1) in the small amount of interior space, I'd like to create a barrier between me and the all in one / inverter...

a) Do you think lining a wooden box with mazed chicken wire would do anything?

b) Do you think putting this around the wires or cables would make a difference on EMF / interference?

Depends on what you want to block.

Keep WiFi, Bluetooth, high frequency (on the order of GHz) and lower (MHz) EMI coming from digital circuits away from you?
Something like copper window screen, small holes but let air through.
Chicken wire isn't small enough; Wavelength of GHz signals can fit through the mesh.

But, if there is a length of wire, cable, etc. (even CAT-6 Ethernet) that extends from inside the mesh enclosure to outside, it will pick up RF inside, conduct along the cable, radiate outside. With varying efficiency depending on frequency and cable length. Only way to stop that is to have EMI filter connectors where it feeds through the shielded enclosure. One design of filter for passing 60 Hz 20A 120V, different filter for Ethernet, RS-485 etc.

Reduce exposure to ELF such as 60 Hz?
That comes from AC wiring including transmission lines.
Best thing you can do for that is twist Line and Neutral together, or at least cable tie close. Same for battery cables, because they carry ripple currents. The idea is to reduce it from a large loop to zero. Side by side wires still have a distance between centerline, but twisted cancels the field with equal amounts of left and right side.

Transformers make 60 Hz magnetic fields, which we are shielding with Mu Metal to reduce the current they induce in metal objects. With small transformers (e.g. 1 kVA) the currents are not huge, but hundreds of mA in some metal objects (or 1 mV if open circuit). Your transformer may vary. This isn't a safety hazard, but affects some instruments.

 

[Kapow_Network]

Depends on what you want to block.

Keep WiFi, Bluetooth, high frequency (on the order of GHz) and lower (MHz) EMI coming from digital circuits away from you?
Something like copper window screen, small holes but let air through.
Chicken wire isn't small enough; Wavelength of GHz signals can fit through the mesh.

But, if there is a length of wire, cable, etc. (even CAT-6 Ethernet) that extends from inside the mesh enclosure to outside, it will pick up RF inside, conduct along the cable, radiate outside. With varying efficiency depending on frequency and cable length. Only way to stop that is to have EMI filter connectors where it feeds through the shielded enclosure. One design of filter for passing 60 Hz 20A 120V, different filter for Ethernet, RS-485 etc.

Reduce exposure to ELF such as 60 Hz?
That comes from AC wiring including transmission lines.
Best thing you can do for that is twist Line and Neutral together, or at least cable tie close. Same for battery cables, because they carry ripple currents. The idea is to reduce it from a large loop to zero. Side by side wires still have a distance between centerline, but twisted cancels the field with equal amounts of left and right side.

Transformers make 60 Hz magnetic fields, which we are shielding with Mu Metal to reduce the current they induce in metal objects. With small transformers (e.g. 1 kVA) the currents are not huge, but hundreds of mA in some metal objects (or 1 mV if open circuit). Your transformer may vary. This isn't a safety hazard, but affects some instruments.

I'm kind of new to this issue. Does ELF mean Electro-magnetic Line Frequency or did you mean EMF?

If I put some type of tape

Amazon.com

or fabric

Amazon.com : copper fabric emf shielding

Let me know if you recommend any particular specs, brand, or type.

My guess is that something will come out of the area with holes (so try to make the holes not aim to where a person might be). Does that sound right in general?

Note @Hedges I had never realized that tying lines together could be anything but an aesthetic waste of time. Thanks. Also, you said AC lines, but wouldn't this apply to DC lines too?

I wasn't specific enough. When I asked if some type of EMF shield would "do anything" I also wondered whether ricocheting or compounding EMF / ELF might damage the all-in-one inverter or its components.

In a general sense, it seems like @fhorst suffered some serious reactions (even fire) from EMF being in places where it should not be.

I want to direct the EMF away from persons, but not damage equipment. Not clear yet on how to ground things in a trailer (currently the trailer is on wood blocks and then on cement next to a house that has a house wire ground appx 10 feet away behind a garage wall... BUT there is a patch of dirt about the same number of feet away wherein I think a ground pole might go a few feet (no hole required into the house wall!)).

As I write this out, I'm realizing that maybe I need to do some research on grounding solar panels and batteries in RVs and trailers.

In the future this trailer might be on some dirt. I doubt the soil will have higher than normal ore content (as seems it does for @fhorst ) but I can research it's composition. Worst case: if on the road, there does not seem to be a nearby patch of dirt, BUT the trailer is not on wood blocks, won't the rubber tires ground out the frame? So then maybe I need a ground to the metal frame just like in a car, and while traveling that's as good as it gets.

 

[Kapow_Network]

I checked Will's channel, and nothing comes up using search words EMF or ELF (or typed all out unless I misspelled). Later I may check elsewhere and post if I find anything helpful online.

 

[Frank in Thailand]

Here is an article that may help you, fHorst

https://electrical-engineering-portal.com/how-dangerous-are-induced-currents-in-transmission-towers-and-poles

Thank you for the link.

Where I live, only electricity lines are the once we make
8km from the nearest 230v pole, higher voltage electricity about 10km.
(Yes, surprised to see, over 2km 230v lines...)

While different location, the basics stay the same.
Electricity does travel by air
And does charge objects.
DC 50v and 350v "high" current will radiate.
Electricity traveling in the air is, according to my research called electrical magnetic field. EMF
Where magnetic and electricity are brother and sister,

AC 230v, I don't worry about.
Small fields that will give some noise if utp cable is attached to that cable when drawing higher watts (+2000)
Unless important server to server connection, not anything to worry about

Just unexpected noticeable charged items close to the battery and inverter.
And unexpected crashes of the computer that was close.
Different location solved it instantly.

Making EMF shielding on the "old" location had the same result (stable computer)
Computer in my situation is an open "rig" (setup) crypto mining setup, who uses about 650-700W 24/7.
And makes about $17.50-20,- each day.
Without additional costs for electricity
(Perhaps less longer battery life as they cycle a bit deeper. Usually 60% per evening/night, so 40% left)
Rain season...
The mining computer works on reduced power, not enough solar from the 43 X 320W panels.
Sunny season?
Batteries are fully recharged before noon.
I could use 2000 watt or more for mining
My setup is made for the rainy season as we don't have real backup options.
(We do have generator on LPG that starts automatically, getting the 30kg (15L) cans to our home is a different challenge, especially during rainy season with muddy clay "roads".. (more like sliding a slippery slope)
Lol

 

[Hedges]

I'm kind of new to this issue. Does ELF mean Electro-magnetic Line Frequency or did you mean EMF?

Elf - Wikipedia

en.wikipedia.org

Extremely low frequency - Wikipedia

en.wikipedia.org

 

[Hedges]

If I put some type of tape

Amazon.com

or fabric

Amazon.com : copper fabric emf shielding

Let me know if you recommend any particular specs, brand, or type.

My guess is that something will come out of the area with holes (so try to make the holes not aim to where a person might be). Does that sound right in general?

That tape says conductive adhesive, which is good for this purpose. It can be used to seal seams of metal boxes for EMI reasons.
Fabric is flexible, would probably attenuate less.

These techniques can attenuate RF fields, reducing them sometimes 100x to 1000x. Higher frequencies are easier to attenuate, except if there are holes high frequencies can slip through.

Speed of light/radio waves in air is 300,000,000 m/second. 300 MHz has wavelength of 1 meter. Half wave is 0.5 meters; if a hole is that big or larger, wave passes through unimpeded (but rest of surface block it, so like light coming through a window but not through walls.)

GHz range of WiFi and Cellphones is some cm wavelength. The mesh of fabric or window screen would be a decent block up to 40 GHz or so.

All depends on what you're trying to do - block digital logic from causing snow on a TV set? Prevent spying on your electronic operations (see "Tempest")? Avoid possible biological effects? Survive EMP/CME event?

Cables bundled or twisted reduces radio waves from AC. It reduces steady-state magnetic field from DC. As I noted, inverter cables carry 60 or 120 Hz and higher harmonics, not just DC.

I don't expect most EMI environments to deliver enough power to ignite anything. You'd pretty much have to go out of your way to accomplish that.

 

[Kapow_Network]

@Hedges Thanks.

All depends on what you're trying to do - block digital logic from causing snow on a TV set? Prevent spying on your electronic operations (see "Tempest")? Avoid possible biological effects? Survive EMP/CME event?

Geez - the way people advertise EMF shielding for biological effects, I thought shielding me against higher susceptibility for biological effects would ALSO do all the above. ... It seems like, on top of shielding, the best thing is to sleep as far away from the "harmonics" / waves / equipment as you reasonably can.

Anyway, my main interest was to shield for biological effects. As we all "get used to" tons of networking equipment not just cellphones, I think it makes sense to try to keep the harmonics from leaking. What I had thought though, was that if I lock in the all-in-one's EMF waves, it increases likelihood that the all-in-one's bluetooth transmitter / parts etc might break or fail. Even if it's UL listed, it was probably NOT tested with the waves being boxed in etc.. And perhaps other internal electronic parts might deteriorate more quickly too. What I sense is this starts to get speculative.

Probably at 145v I won't create a fire or meltdown like @fhorst had, but I should plan to stay nearby at first, and take some before and after measurements of waves, bluetooth functionality, other functions, etc. OF COURSE, I hadn't budgeted time for that. Not even sure of best wave reading machine for that... But I'm either worried about it (bio effects / equipment effects etc) enough to do the extra work or I'm not. Ugh...

Definitely admire the crypto rig (especially off grid!).
On the one hand I want the HEAT from my electronics / inverter / is a battery bank ever hot when the sun goes down?
On the other hand I don't want the EMF...

Anyone else sit with a laptop in their lap everyday and wonder what effect it has on any potential future generations..?

is NOT a good test as comments point out because it uses 2 layers instead of one.

In response, the creator (who seems to know his stuff) points to:

SaferBody™ from SYB - Laboratory Tested EMF & 5G Protection - SYB

At SYB, we take our product claims very seriously, and we want our customers like you to know that. That’s why we post our EMF product testing results.

www.shieldyourbody.com

which says "This test was performed on July 30, 2019"
BUT the creator ALSO said would do another video test when covid died down,
BUT reality is that it's been about 2 years now. No new test.

Hope some of this rambling helps someone!
I'd ask whether silver threaded underwear itch less than copper ones, but I don't want to go too far off topic .

 

[Ironman]

Have you attempted to measure this voltage between the rods on the battery box and the concrete?

I can' find it at the moment but I remember reading about the voltage that develops on an antenna and they based a calculation on voltage per height above ground.
I remember Art Bell from the After Dark radio show got hit with 400 volts of electricity from the air when servicing his antenna, and fell and hurt his back enough that he had to retire. Found this stuff, and I apologize for its source but it does discuss this phenomena.

How to Collect Free Energy from Atmosphere - Homemade Circuit Projects

A free energy collector circuit helps to convert surrounding radio frequency waves to electric power and can provide 40 watts to 10 watts indefinitely. The Circuit Concept An option to […]

www.homemade-circuits.com

This stuff from an antenna is not a static charge and can collect on any attractant.

 

[Torch2]

Are you sure you have a very good ground for your battery rack. If you are picking up large amounts of EMF, try grounding your rack to a 1/2 inch copper rod going down into the ground a least 8 feet. That's the code here where I live for homes running off the grid. Another good grounding source is a metal or copper water pipe, not pvc piping. - Cement is a very bad ground and will drain your batteries if they are setting on the cement. At least that was the way it was back many years.

Unless you live close to very high voltage power lines or a nuclear power plant, I don't know where you would be picking up that kind of EMF.

Phones give off EMFs, anything electric does.

 

[A.Justice]

Don't make me wear shoes ?️

? Your profile picture makes that even more funny.

 

[ArthurEld]

? Your profile picture makes that even more funny.

I seriously didn't know better when I said that. I wear shoes and I am very careful when working with electricity.

 

[HaldorEE]

Phones give off EMFs, anything electric does.

Current levels make the difference. Signals in phones are measured in mA. Inverters in 100's of amps.

 

[SolarfortheOuachitas]

I’ve had two events at my battery powerhouse.

My powerhouse stores 16 105 amp hour 12 V AGM batteries and my inverter is a trace SW 4024.

On several occasions I have leaned over the battery bank with my cell phone in my hand to look at the output of the inverter.

My cell phone immediately shut down.

In another case I had plugged in my cell phone charger into an outlet next to my inverter with the cord dangling over the batteries and the phone plugged in to the cord.

The phone immediately shut down.

In another event, I had backed my plug-in hybrid electric vehicle close to the doors of the powerhouse so that I could access my tools in the hatchback of the car.

The doors of my powerhouse are insulated with Styrofoam with foil backing.

After working on the batteries for a little while – tightening the connections, I tried to start my car and it wouldn’t start.

I put a voltage meter on the starting battery and it measured 3 V. The car would not start.

Eventually I jumpstarted it and drove it off. I suspect that the cause of both of my problems was electromagnetic force but I’m not certain.

However I no longer back my car anywhere near the doors of my powerhouse, nor do I bring my phone or charger inside the powerhouse.

My system is grounded properly according to my electrician brother and I suspect that EMF is the culprit.

Your thoughts?

 

[Smokin]

When I key up my 10Kw CB radio, Plasma shoots out of everywhere. I had to place the microphone inside a UPS Ground Box to make it stop. Electricity doesn't weigh anything so UPS won't charge you.

 

[Ampster]

Your thoughts?

Perhaps another reason to switch to Lithium.

 

[Hedges]

On several occasions I have leaned over the battery bank with my cell phone in my hand to look at the output of the inverter.

My cell phone immediately shut down.

In another case I had plugged in my cell phone charger into an outlet next to my inverter with the cord dangling over the batteries and the phone plugged in to the cord.

The phone immediately shut down.

In another event, I had backed my plug-in hybrid electric vehicle close to the doors of the powerhouse so that I could access my tools in the hatchback of the car.

...

I put a voltage meter on the starting battery and it measured 3 V. The car would not start.

Although batteries nominally provide DC current to inverter, there is a large 60 Hz ripple current, and there will be higher frequencies depending on how well inverter's switching is filtered.

I previously worked on an issue where a device (hand held blood glucose meter) was disturbed and shut off when a 900 MHz cordless phone was brought near. That induced enough signal to affect its circuits.

Possibly the lower frequencies (10kHz, 100kHz, maybe harmonics into low MHz) of inverter affected your phone.

The car battery itself would be unaffected. Electronics in the car, if not isolated from battery by electronics, could be affected by the EM fields and could turn on circuits. However, to drain the battery they would have to dissipate the power in it, which either takes a number of hours (like running down battery with lights or radio) or would smoke the electronics.

Most likely an existing problem with either battery or connections.

 

[LarsJ]

I have a copper rod in the ground, about 2 meter deep.

Standard "lightning rod"

The rebars in the slap are "grounded" to 6 same pins, about 1/2 inch.

I haven't connected the iron roof structure to the pins yet.
(But made 50mm2 copper wire stick out of the concrete to make connections)

At that time I did not have the right equipment to solder on the wire and connect to the roof structure.

Original idea was to have lighting protection on the rooftop.

I do have protection on the water tower, that's a few meters from our house.
At the middle of the length, if you understand.
That rod is really sufficient in catching the lighting that does occur here regular.

My Thai wife used to be scared for lighting as it does set "houses" (metal sheets and natural roof) on fire here often.
After witnessing several strikes without any effect, she's comfortable now

It would be possible that it gets charged by defective panel.

With 2 sets , one of 18 and one of 9 it's not easy to spot if a panel is producing less.

OK, 15-40v, but is that A/C or D/C volts?
Just a few more things to check for: Disconnect the wire from the ground rod and check for voltage, both A/C and D/C. If nothing, run a wire from the ground rod to the battery setup and connect the negative lead of your meter to it, then touch each rod to check for voltage. If you find some, log it and isolate the batteries from both + and - wiring. Do you still have voltage to the rod? Check the batteries next to the hot rod to see if they are charging (or shorting to) it. Also check the rod to the negative terminals of the batteries next to it. Any voltage or shorts? If so, remove all the batteries and check for damage to the case. Then pull all the rods and sleeve them with shrink sleeve or vinyl tubing. (Don't shrink the sleeve.) If no damage, reassemble everything and check again. If you're still getting voltage, try running a grounding wire to all rods. If you get more than one small arc from connecting it, you're shorting against something. Otherwise, you should be done. OH, one last thing: check that all your grounds inside the house go to a single ground. Ground loops can play havoc with your systems.

 

[A.Justice]

OK, 15-40v, but is that A/C or D/C volts?
Just a few more things to check for: Disconnect the wire from the ground rod and check for voltage, both A/C and D/C. If nothing, run a wire from the ground rod to the battery setup and connect the negative lead of your meter to it, then touch each rod to check for voltage. If you find some, log it and isolate the batteries from both + and - wiring. Do you still have voltage to the rod? Check the batteries next to the hot rod to see if they are charging (or shorting to) it. Also check the rod to the negative terminals of the batteries next to it. Any voltage or shorts? If so, remove all the batteries and check for damage to the case. Then pull all the rods and sleeve them with shrink sleeve or vinyl tubing. (Don't shrink the sleeve.) If no damage, reassemble everything and check again. If you're still getting voltage, try running a grounding wire to all rods. If you get more than one small arc from connecting it, you're shorting against something. Otherwise, you should be done. OH, one last thing: check that all your grounds inside the house go to a single ground. Ground loops can play havoc with your systems.

Just FYI, that system has since caught fire and been destroyed.