hum from nearby high-tension wires?


Hi,

I live about 100 feet or so from a high-tension electrical transmission setup that carries power to a local university. There is also a large transformer station of some kind about 200 feet away.

I have been having pernicious hum problems that do not respond to any of the recommended treatments, and I'm wondering if they could be due to the transmission line or power station. And if they are, what can I do about it?

I would appreciate any comments/suggestions
steverw
I certainly believe being in close proximity to that much of an induced electromagnetic field can cause the type of problems you are having. There have been extensive studies debating whether or not there are health problems associated with this as well (I think the verdict is still out). I don't think there is any type of power conditioning device you can use to get rid of this, since the EM field is permeating everything in the vicinity. You could certainly try these devices, but they probably won't address the issue, since this EM is radiating into your electronics directly, despite any conditioning measures. You could try extensive MU-metal shielding, building a Faraday cage, in effect, but this is expensive and there are no guarantees. When I was young, we had high-tension lines (in excess of 2kV) about two miles from my home. These were huge, scary looking metal towers which emmitted an audible hum at all times. We used to go up there at night in the summer with standard 4 foot flourescent tubes which would glow at nearly full intensity as one came close to the towers.

My advice is to move.

-Richard
Get yourself some kind of battery powered audio device...a portable radio for example. See if it hums, and what happens as you walk towards and away from the transmission lines. If it doesn't hum, you have a problem with your own system.
If you can do it, I'd suggest moving. If the overhead power line are affecting your system, imagine what they're doing to your body.

All of the information your body passes, is passed electrically. Strong electrical signals interfere with the transmission of information.

Dr R. C. Brockhaus
Hey, nothing like scaring the guy. Verdict is indeed still out on EM/RF impact on human health. As far as your hi-fi, that is a problem. You can try sheets of ERS cloth and move them around to see if there is a particularly sensitive piece of equipment. could also try humbuster. I assume you have checked to see if it is coming in through your CATV.
These aren't the monster tower kind of transmission lines for long distances, they are local distribution type within city limits that have lower emissions. The only devices affected are sensitive ones like phone preamps and pickups (and, I suppose possibly our nervous systems, although I wonder how EM radiation of this sort could have signifcant coupling with our electrochemical wetware, I seem to remember that our nerves conduct in a different way ("sodium pump"?) than metal wires).

Anyway, thanks for advice, I'll try the radio and fluorescent tube tests. My grandson would be thrilled if we could get the full lightsabre sound and audio effects.
While it is true that the studies are mixed there are studies showing that exposure to electromagnetic fields have adverse effect on cells at the chromosomal level as well as the immune system. There may also be a relationship to certain cancers and neurological diseases.
Another possibility is the university complex itself is the source. There are probably large motors for air condioning and elevators, some of which may be variable frequency drive, that puts noise in the power grid. Another possibility is that the university has a cogeneration plant - generating electricity to the site and selling some power back to the utility. This backfeed will also put noise in the line. In short, that facility may be the culprit and not the substation. Your only solution may be a shielded isolation transformer for the whole house (way too expensive) or for the audio circuits. The xfmr should be grounded at its location.

Also, power quality is an issue that your utility has to address. Whether it's voltage variations (sags and dips) or noise, they are required to have a means of hearing your complaints and to make a good faith attempt to correct these issues. Let them know - maybe they think everyone is happy as they send out their bills.

As a side note, a friend has an office directly across the street from a utility small-scale generating plant. There is no problem with AM or TV reception. The only noticable effect is when you drive only past the front gate and the AM in the car briefly hums out.
Based on your second post, I don't think the power lines are the problem. EM fields extinguish rapidly in air - if you were between them and the ground (i.e., under the power lines) then there could be an issue but not if you are 100 feet away. My guess is you have a bad ground. I have seen entire houses with bad grounds so don't rule that out!

However, do try the fluro tube bulb test but I bet it only works directly under the power lines, if at all (too low voltage lines).
>>"These aren't the monster tower kind of transmission lines for long distances, they are local distribution type within city limits that have lower emissions."<<
[Steverw]
>>>>>>>>>

Just curious how high off the ground would you say the power lines are?

How long are the insulators that the wires are supported by?
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>>"There is also a large transformer station of some kind about 200 feet away."<<
[Steverw]
>>>>>>>>>>>

That sounds like a Substation. Just an example of a Substation in a residential area, 3 phase 69KV feeding the Substation 7.2KV/13.2KV 3 phase 4 wire out.

Substation near a large university could be 169KV feeding the Substation.

Best guess, how high are the power lines, and the size of the insulators?
Jea48: maybe 80 feet high. Insulator about the height of a large owl or hawk (maybe a foot?) (I often see them sitting on the line).
Dreadhead: well, consider that I live in an earthquake zone and commute some 75 mi per day; these are probably my biggest risks. And just being 49 years old has its risks - bell-curve-wise, many of me are already dead. I don't smoke, but I like wine; my cholesterol is moderate, but on the high side (along with my weight). And I drink tap water. EM from the power lines ranks below these other things on my list of threats to life.

At least I want to enjoy music while the radiation crisps my genetic material.

(Please note that I'm attempting to make light of the situation, I hope no one is offended by these off-hand remarks. All of us have had loved ones who have been affected by various unpleasant health issues, and I mean no disrepect, I'm just being flippant to put some emotional distance between me and the consequences of taking risks.)
Update: it may be due to poor grounding of the house. I found the ground spike, connections to it are corroded. Plus I found a degenerate cable connection that was not in use. Oddly, disconnecting this hidden cable connection actually made the hum louder. I need to get an expert in here to asses the house grounding.
Steverw...Please do the portable radio check. This would probably set some people's minds at ease about radiated EMF.
Just as I figured. You'd be amazed how many houses have bad grounds. Keep us posted on the repair.
I agree with Aball. If you have a metallic main incoming water line that should be your main earth grounding electrode. Call an electrical contractor and have him check all the earth ground connections, both ends.

Be careful messing with the earth ground connections. Sometimes a difference of potential, voltage, can exist between the ground wire/s, (grounding electrode conductor/s), and the earth ground/s, (grounding electrode/s).
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01-31-06: Steverw
>>"Jea48: maybe 80 feet high. Insulator about the height of a large owl or hawk (maybe a foot?) (I often see them sitting on the line)."<<
>>>>>>>>

Sure sounds like 69KV. No Kite flying near those lines.
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Turned out to be a loose connection.

There was no radio noise, even right under the wires.

But now I know a lot more about grounding, thanks for the advice.
Two things about so-called 'harmful' EMF - 1) The fields decrease at a square of the distance, i.e. if you double the distance away from the line, the field intensity goes down by 1/4, triple the distance 1/9, etc. So while there is detectable electromagnetic radiation below the lines, its pretty weak at ground level. 2) If EMF from power lines causes cancer,etc., why isn't there any epidemic among power company Lineman (there isn't). And no, I don't work for an electric utility. But there is No solid proof of EMF from power lines being harmful (unless, of course, you come in contact with one and are grounded)...
Steverw, have you called someone out yet to check your grounding?

What part of the country do you live?

With a plastic main incoming water line you should have a minimum of two 8ft ground rods. One wire coming from your main electrical panel to one of the grd rods and continuing to the next.
Minimum of 6ft apart, 8 to 10ft apart is better. Three or more ground rods is better.

If you have not called someone to come out yet, when you do have the electrician verify just how many grd rods you have. Unearthing the tops of the rods, cleaning and reterminating them as needed.

Depending on what part of the country you live, soil conditions is very important for the type of earth grounding electrode system you have. And depending how old your home is the electrician will be able to advise you what is now required by local codes for your area.

Also while the electrician is there have him check and tighten all termination in the main electrical panel.
Jim
Jea48: I live in Santa Cruz, CA. I've called some local electricians, but so far I haven't invited anyone out yet because I want to research a little bit more.

Specifically, our house is on a hill that is a big rock. Dig down 8" and you hit this yellowish rock. This area used to be quarried for limestone. I think the type of geology is called "karst". The rock is not hard like granite, but it is hard enough that you need to chip at it with a pick to make any sort of hole.

The thing I'm wondering about is whether this rock (is it limestone?) has good grounding qualities. The local electricians I have called say they don't know and don't have the measurement tools to test, all they do is visually check compliance with local codes. Do you know if there is a lab somewhere I can send the rock for testing?

In my own visual inspection, I can see that we have just one ground rod, which appears to be just some rebar pounded into the ground; I don't know how deep it goes. The earthing strap is all corroded. So this definitely needs some attention!
If you can't drive a rod down into earth, another approach is a metalic mat, say 4X8 feet, which you bury as deep as posible.
Steverw, I have no idea what to tell you. The Electrical contractors in your area must know how to deal with your situation. They should come out to your home for free and give you an estimate on how much it would cost to fix your problem. Ask lots of questions, don't be shy. What kind of electrical earth grounding Electrode system do they recommend? How deep will they need to go? How much $$$$.

Here is a Link to some NECA/IBEW electrical contractors in your area I believe. Did you call any of these? I think you will have the best luck with a Commercial/Industrial Electrical Contractor.
http://www.mbccneca.org/member_list.htm
Are any of them in your area?

You have one hell of alot of power around you. I guarantee you that Substation has earth grounding up the Ying Yang, lightning protection.

What ever you do to solve you problem post back and let us know what you ended up doing.
Jim