No quibbles with the science, but the terminology. I’m an electrical engineer, though not a specialist in the power industry. But I have never seen the phrase “high tension” except from non-technical sources, such as news reporters. I have seen signs in languages other than English around transformer equipment, which says “haute tension” or something like that, which is French for “high voltage.”
That makes me think that “tension” is French for “voltage,” otherwise generically called electromotive force or EMF (not to be confused with the EMF that is an abbreviation for “electromagnetic field”).
In general, I think it’s preferable to use “high voltage” over “high tension.”
Well, I do have a quibble about the science: Cecil says “Some background. Magnets and moving electric currents radiate energy into space,” but magnets do not automatically radiate energy… and all electric currents move by definition! I think what got transposed in the proofing process was the word ‘moving’, and Cecil actually meant “Some background. Moving magnets and electric currents radiate energy into
space”. Right?
In my experience, you are correct. I’ve used the phrase “high tension” before and have taken flak from other engineers about using an unprofessional term. Even though the phrase is sometimes used by professionals (as in QED’s link) there is an attitude among many engineers that the phrase “high tension” should not be used by engineers.
When I worked in the power industry, we almost never referred to a line as a “high voltage” line. We would say what the voltage was. In other words, we wouldn’t refer to the “high voltage line” in a particular location, we’d call it the 33kV line, or whatever the voltage happened to be on it. This also helps with the confusion you have when there are multiple voltage lines running through the same area.
By the way, this week’s topic is something I’ve been following for years. One of my professors in college was doing some of the early research into the subject of the hazards of power lines in the early 1980’s when this really became a hot topic. Statistically, people who live near power lines don’t live as long as people who do, but decades of research haven’t found any good reason why. As my professor used to say, it may just be that people who choose to live healthier lives also choose not to live next to power lines.
Cecil managed wade through all of the crap and biased sources of info out there, and (IMHO) really hit the nail on the head with this article. It’s not often you find a fair and unbiased opinion on this topic. I think Cecil deserves an extra atta boy for this one.
Our local utility has a guy who’ll come out and measure the strength of the electric field at your house if you’re worried. An , since we live near one of the big Bonneville Power lines, we had that done. Turns out the electric field attenuates really quickly, so there wasn’t much present at our house. But his most convincing statement was economic:
“If there was any problem, we wouldn’t bother to cover it up; we’d just pay people to move or whatever, and then we’d just raise the rates to cover it. We’re a public utility. We don’t have to worry about profit and loss.”
“Tension” for “voltage” is (or at least used to be) normal British usage. (For example, one spoke of an “H.T. lead” from the distributor cap. For some reason, it has been picked up in the US only for power-distribution lines, where it is (or at least used to be) very common.
It may well not be proper in US engineering circles – if I were an engineer, I’d be annoyed by it, too – but it’s been a standard lay idiom for as long as I can remember, and I’m 58.
That’s my experience in the industry also, however when a generic phrase like “high voltage” was used, it was generally used for transmission lines, rather than distribution. Roughly, “high voltage” = above 38kV or so (transmission lines), “medium voltage” = “600V to 38kV” (distribution lines), and “low voltage” = under 600V (secondaries of distribution transformers, supplying power to customers). Sometimes I’ll run into the term “extremely high voltage”, used to refer to 500kV or higher transmission lines.
I also seem to recall it being used with reference to Cathode Ray Tubes and electronic valve equipment. Just one of those early British terms that has stayed with us.
Anyone debating this topic really needs to pay a visit to Niagara Falls, NY. You’ll find few places in the country (if not on the planet) with a higher concentration of high tension lines. If it were indeed true that their existence caused cancer, or anything else for that matter, the people in that city would be dropping like flies. I live near an electrified rail line in the Philadelphia area, and I hear the same buzzing from the lines that feed the catenary. I’ve heard of no such similar correlation between the existence of these rail lines and any link to cancer.
I’ll just add that as an Engineer who works in the power industry and who’s been to hundreds of power plants over the last 15 years, “high tension” is used, but what engineer_comp_geek said is more typical - people usually say “125kV line” or something like that. I could not estimate to what extent “high tension” is used in place of “high voltage” other than to say neither is uncommon enough that I note it or its absence. Just IMO.
Another terminological nit: There are electric fields, magnetic fields, and electromagnetic radiation. Steady electric fields develop in response to a charge and magnetic fields in reponse to a magnet. Steady fields lead no radiation. Non-steady fields of either kind lead to EM radiation (emission of photons). An electric current is a moving electric field and thereby emits radiation. Sixty cycle current leads to very long wavelength (5000 km unless I have lost a decimal place) radiation.
FWIW I always took the word tension in ‘high tension wires’ to mean the actual ‘mechanical’ tensile stress in the wires themselves, as the towers are placed very far apart, and the wires must be in a great deal of tension over standard utility pole lines as not to sag too much.
Still not quite. A steady current will result in a steady magnetic field, and still no radiation. A changing current, however, such as is found in AC, does radiate. And you’re correct on the 5000 km wavelength.