wiring---radiation

teddy123

Have done a lot of reading on electromagnetic radiation and health. Do any of you feel theres a danger to our health from all the electric current in our homes. I must say what I have read really worries me. For instance it says we should not sleep beside or over where there is a clutter of wiring. I've been in a large new build lately and the amount of wires going across the ceiling, down walls etc was unreal. Does every house have a standard amount of electricity coming in also is there the same amount of current running through the wires in the night time when the appliances are not in use as when they are. I would be really interested in getting your views please as it is something that bothers me a lot.

Stoner

Teddy i have similar concerns, I've read up on some "sick" buildings and runs of electrical cables can be an issue. One of the main things is that in a house, you only have a single phase sypply (95% of the time) in some cases in buildings etc there are three phases, if any of those cables is run in a different way to the others the effects are magnified. But you are dealing with balanced loads in a standard house, this is a good thing.

Cables run straight down a wall, and mains runs in parallel in a house keep the radiation down. Also the amount of current passing through a cable is directly proportional to the strength of the field, with electric fields it also determines the direction.

So a nice clean electrical installation, runs in parallel, single phase, turning off power at night all help to reduce (and completely remove) the fields at source.

Microwaves are very bad also, I have tested mine with electrical EMF, and radiation meters. I have my microwave in a press with a flip up door. the difference closing the door while the microwave is on is huge. The "dangerous" level area goes from a radius of 2M to 0.5M (I dont use the microwave in a closed press now, I'm not recommending it, I just keep my distance from it (when in use) and use it very little.


You can buy a meter with a three level indicator on it for about €30 if you want, with red (dangerous), orange and green lights. So you can test an area you are working on.

You will see a differece when things are on and off, for example at a light switch, it can go from orange to red when the lights are on (2CM from the switch)

teddy123

Thanks Stoner for your very helpful reply. Where can you buy those meters? I'm definitely going to get one of them.

sunnysoutheast

This must be a wind-up surely?!?

The electrical fields in your house are killing you? Get a grip! You'll be more at risk from eating a chargrilled chop at a barbecue once a year.

What you want to watch out for is Oxygen Dihydride - kills hundreds every year. It's a scandal how it hasn't been banned.

SSE

ART6

sunnysoutheast wrote: »

This must be a wind-up surely?!?

The electrical fields in your house are killing you? Get a grip! You'll be more at risk from eating a chargrilled chop at a barbecue once a year.

What you want to watch out for is Oxygen Dihydride - kills hundreds every year. It's a scandal how it hasn't been banned.

SSE

Quite! You have to face up to the fact that sooner or later something will kill you, but unless you permanently wrap yourself in high voltage, high current cables, it won't be your house power supply:)

teddy123

You will get plenty info on the net on this subject. www.bioinitiative.org and www.imafish.co.uk are just 2 such sites. Hopefully you're right and there is nothing to worry about but no harm in researching these things. Maybe years ago people laughed when Radon gas was being spoken about but now its compulsory to put radon barriers in every new house.

sunnysoutheast

you'll get plenty on the 'net on any subject - aliens, 9/11 conspiracies, cars that run on water, faked moon landings, yetis, Keane to Liverpool - it doesn't mean that any of it is necessarily true!

SSE

teddy123

It does'nt mean its not true either.

Stoner

i cant find the name of the meter i got, but I gave it to another boardsie so I'll ask him, sorry for the delay.

sparkfireman

I did my aprrenticeship with the ESB. and although i hate them, they investigated and researched for years on the transmission lines. The (440,000v) lines from powerstation to powerstation and they concluded no threat.

The radiation u want to look out for are: TV, the Ground (radon), microwaves, the SUN!, basically everything in our lives. The Average human absorbs a certain amount of radiation that over their lifespan causes them little illeffects....

Dont turn into recluses guys!

bibibobo

wouldn't be too worried about electrical cables to be honest. we are all subject to radiation on a daily basis. as i type there is cosmic radiation passing through my body giving me a radiation dose. every time i take a transatlantic flight i receive the equivalent of a chest X-ray. every time i eat fish i receive a small dose also.

watty

Apart from lighting switch wires in ceiling, the current in wires to plug sockets, light switchs etc is equal and opposite and thus the magnetic fields cancel. RF is almost nothing. 10,000x or more from your local Star (the Sun).

There is no evidence in over 100 years of using AC mains electricity that even a single wire (1000s x field compared to twin flex) has any effect at all.

Even with WiFi, Mobile Phone etc with people that claim to be sensitive, double blind tests show no significant correlation (i.e. they did as well as if they tossed a coin to decide).

I can measure easily the "radiation" (i.e. radio signal) from GSM, WiFi, TV, Radio, Marine Coastguard, Shannon Volmet (even in Dublin), but more than a few cms away I can't detect AC Mains (with test gear, not my head). Only RF interference from "gadgets", CFL replacements, Switch mode Plug Chargers etc, and those are about the same level 50cm away as R4 LW from Droitwitch in England received in Limerick (i.e. TINY!).

If something blots out your radio, TV or WiFi, then investigate. A lot of Mains wiring probabily reduces the RF in your house.

"Radiation" as in Cosmic Rays, X-Rays from decaying Radon Gas leaking into your house from the rocks below, Ultraviolet from a clear sunny sky are all highest risks.

Microwaves as in Ovens or Radar will give cateracts or surface burns if you are exposes as much as cooking food or waveguide feed to radar dish. You'd have to have a very faulty Microwave and stand at it everyday to get a cateract outside it. We have been using Radar/Cooker power Microwaves for nearly 80 years. No confirmed headaches or cancer, only cateracts and burns by mistakes. Deaths only AFAIK only from touching the wrong part of the 500V to 6,000V powersupply internals!

Lower frequencies (TV & Mobile Phone) you need to be nearby to kilowatts, even then you get burns. Very high power RF is used for some kinds of plastics welding and specialist furnaces. From 500W at several mm concentrated to 100,000W induction coils (all energy inside coils). From 15MHz to 600MHz. Mobile phone is typically less than 1W. A phone mast might run 20W or more, but inverse square law means that if you ar 10m from aerial the power is 1,000 less than a phone 10cm away from your head. The Masts have a 10 or 20 degree vertical beam width so as to not waste power, which means that just below mast is LESS power than 1km away!

If there was a risk, the safest situation for a school would be to have it on their own roof. I think the whole phone scare invented by middle class vocal NIMBYs that don't like the appearance of a lattice mast.

Radio signals are what is called "non-ionising". Cosmic Rays, UV and X-Rays are Ionising radiation.

Mains is only 50Hz. You need 10 miles at least to launch radio waves at that frequency (poorly) as 1/4 wave is 300,000,000/(50x 4) = 15,000km for a "whip" aerial!

An efficient coil to couple a magnetic field needs 10s to 100s of turns on a laminated soft iron, iron dust or ferrite core... Which only couples at less than 1mm to a similar core with a winding (A transformer). You need massive power and maybe super conducting coils to couple 50Hz into our fleshy bodies. (Seen an MRI scanner and the warnings? It is used partly as it's safer than X-Rays.) You could wear mains cable coils all your life and not get a fraction of MRI power.

It seems Dizzy Blonde Lucille Ball (I love lucy) started the urban myth of radio pickup

BUSTED:
Scroll down somewhat
http://www.mythbustersfanclub.com/mb2/content/view/26/27/

And Lucy may not have invented the story, it could have attributed to her:
http://www.snopes.com/radiotv/tv/fillings.asp

watty

Stoner wrote: »

Microwaves are very bad also, I have tested mine with electrical EMF, and radiation meters. I have my microwave in a press with a flip up door. the difference closing the door while the microwave is on is huge. The "dangerous" level area goes from a radius of 2M to 0.5M (I dont use the microwave in a closed press now, I'm not recommending it, I just keep my distance from it (when in use) and use it very little.


You can buy a meter with a three level indicator on it for about €30 if you want, with red (dangerous), orange and green lights. So you can test an area you are working on.

You will see a differece when things are on and off, for example at a light switch, it can go from orange to red when the lights are on (2CM from the switch)

If the meter is affected by a light switch it's useless for a Microwave oven. You want a proper calaibrated 2GHz to 3GHz "near field meter". Not cheap. A cheap meter will give false readings.

The only potentially dangerous RF device in a normal home is the microwave, and is only a problem if the door or seal is physically damaged or tampered with.

muggyog

While I agree with 99% of what Watty has said, I believe that there is a worse offender than the microwave oven and that is the Mobile Phone. As suggested any effects from radiating ( or potentially radiating ) devices are greatly reduced by distance from it. Also duration of exposure is a factor. Hence my concern regarding Mobile Phones. My daughters actually sleep with their mobiles charging beside them and spend amazing amounts of time with them pressed against their brain.

Your TV/ Monitor is another likely suspect but with the demise of the CRT this is becoming less of a problem.

Also agree about measuring device, to get proper readings ( not three levels ) expensive exuipment is required and would have to be calibrated properly. Would be suspicious of the accuracy of a 30euro meter.

This is not to say that Electromagnetic Radiation does not affect humans ( and animals ). After all the brain runs on electrical impulses and anything that interferes with that is not a good thing ( except drinking!) but natural radiation probably has a greater effect than 'man made'.

I think you will be OK Teddy, there would be negligible current flow in your cabling at night time hence negligible radiation.

Stoner

watty wrote: »

If the meter is affected by a light switch it's useless for a Microwave oven. You want a proper calaibrated 2GHz to 3GHz "near field meter". Not cheap. A cheap meter will give false readings.

Good point, my answer made it seem as such.
The cheapo meter will give an indication of the electic fields caused by AC currents (lights etc) but not Microwaves (although the AC current powering the Microwave will give you a reading on such a meter, it is not measuring potential leaks, just the fields produced by a unit typically using 600-1000W)

watty

muggyog wrote: »

Your TV/ Monitor is another likely suspect but with the demise of the CRT this is becoming less of a problem.



I think you will be OK Teddy, there would be negligible current flow in your cabling at night time hence negligible radiation.

LCDs & Plasmas often produce more RF energy than CRTs. More Radiation from sun than X-rays from CRT. Too much glass.

Even if you driving a 3 bar electric fire, you won't measure any radiation from the wiring. The quilt may catch fire though.

watty

Stoner wrote: »

Good point, my answer made it seem as such.
The cheapo meter will give an indication of the electic fields caused by AC currents (lights etc) but not Microwaves (although the AC current powering the Microwave will give you a reading on such a meter, it is not measuring potential leaks, just the fields produced by a unit typically using 600-1000W)

I'd worry more about the Microwave Ovens RF leak than power used.. I saw a very old one in an office once and the door looked very worn. I demonstrated the RF near field meter to the Strong Personality in Accounts (newly Pregnant). There was a new oven the next day It produced no reading on my meter at all, even though x3 more powerful.

Basically if it is CE marked, reputable make, < 6 years old and in good physical condition it is VERY likely to be fine.

If it interferes with your WiFi, be suspicious. (nearby band). Even so, if faulty, the main risk is cataracts if you stare in the door...

Hoagy

watty wrote: »

If it interferes with your WiFi, be suspicious. (nearby band). Even so, if faulty, the main risk is cataracts if you stare in the door...

Firm I used to work for supplied spares for one of the major brands. One of the service guys was on a call and he noticed there was no metal grid in the microwave door. The woman admitted she got her husband to remove the mesh because she couldn't see inside properly.

DublinDilbert

watty wrote: »

LCDs & Plasmas often produce more RF energy than CRTs.

How does an LCD produce more RF and a CRT?

The internal switcher for the power supply and the one for the back light would be very EMC quiet, otherwise they would not pass basic emissions tests.

watty

Actually many LCDs and plasma would fail decent tests. The testing scenario is wrong. One major manufacturer's panel met EMC, but no-one could use a MW, LW or SW radion in same house. They added a transparent metalisation on screen.


The RF of the backlight is typically x10 worse than main SMPSU. But that is not the issue. The Plasma and LCD work by vertical array of wires on one side and horizontal array of wires on the other side. One set of wires is generating harmonics of 15.625, 31KHz or 64KHz etc, the other set of wires generating harmonics of basic dot clock 6MHz to 200MHz depending on resolution.

My laptop LCD is so bad it blocks VHF reception nearby and VHF or UHF handheld Transmitter malfunctions on transmit nearby. It meets all Canadian, EU, American and Japanese EMC limits.

None of my CRTs produce any interference. Not even 20" 1600x1200 Computer Monitor.