Magnetic Fields Meter 1

[charcoal]

Hi
We are planning to purchase a new Magnetic Fields meter and currently looking at the Narda EFA 300 Exposure Field Analyser (Electric & Magnetic Fields)

http://www.narda-sts.com/en/produkte/efa.htm

We plan to use the meter to measure Magnetic Fields from subtransmission (66kV & 33kV) and distribution feders (22kV & 11kV) including Sub Stations. This meter also measures Electric Fields which is useful.
Has anyone used this type of instrument? If so any comments on ease of use, accuracy, support service, maintenance required etc. would be appreciated. Also has anyone used a alternative manufacture which they would recommend?

 

[Skogsgurra]

I wouldn't support this kind of measurements at all. There is no evidence and no scientific proof that any magnetic or electric field has any effect on living creatures. Including human beings.

We (Sweden) have one of the lowest recommended ELF limits in the world (o.2 microtesla) and that limit has been established without any regard to biological effects. I even suspect that someone plugged 1:s (1 A, 1 m) into Biot-Savarts formula and got 0.2x10^-6 in return. It has caused lots of unnecessary angst and costs. It has also given charlatans a possibility to make a lot of money offering less informed individuals "shielding" of their homes.

I have a workplace in the vicinity where people have been working in a 50 - 60 microtesla environment for more than thirty years. No problems at all. There are also international limits saying 600 uT and 1500 uT. And no problems there either.

So, unless you are going to test for hundreds of microtesla; don't do it. It is a completely meaningless measurement and it will only bring problems. Society has not found a rational way of handling the results of these measurements. Not yet.

Gunnar Englund

http://www.gke.org

 

[vic3fan]

Herr Gunnar,

Thanks for sharing the data-it's impressive and it's not so handy to find it out from other resources (I think).

On the other hand, why not encourage them to do these measurements if they have time and money for it? Let's see what they come up with. It's better to spend the money on scientific research instead of wasting millions of dollars in meaningless golf, soccer or any other sport tournaments.

 

[Skogsgurra]

The problem is that the more people measure and publish measurements, the more people worry. The reasoning goes like this: "If they do measurements, then there must be a risk involved. Otherwise they wouldn't measure. Would they?" That is why you shall not do measurements. They have no purpose, but they make people nervous.

Study this document.

http://www.labour.gov.sk.ca/safety/radiation/e-l-f/printpage.htm

The snip from the document below summarises the status of today's knowledge. Please note that "more research" is not asked for. We know enough. Magnetic fields have no adverse (or positive, I think) health effects.

"The overall view obtained from the research literature indicates that while some biological effects of exposure to ELF electric and magnetic fields occur, there are no resulting adverse health effects from these exposures. The observed biological effects have not been shown to be significant in terms of a health hazard. Therefore this lack of cause/effect evidence for disease induction for the exposure levels of concern to workers and the general public prevents the derivation of guidelines for protection against any chronic or long-term effects at typical low levels that most people are exposed to."


Gunnar Englund

http://www.gke.org

 

[nbucska]

Gunnar:
I think you deserve a star for chanpioning reason.

We accept risk of driving for easy/fast transportation
danger for coaLminers and smog for energy -- well,
if transmission lines have some risk, the risk of the
fields is certainly less than the risk of freezing
without electricity.




Plesae read FAQ240-1032
My WEB: <

http://geocities.com/nbucska/>

 

[charcoal]

skogsgurra
Thanks for your reply.
Fully accept at respect your opinion, however the forum is not about EMF standards, Guidelines, Health effects or similar.

The aim of this forum is to identify peoples experience with a particular EMF instrument, identify the pro's & con's of the instrument or even an alternative solution.

While your reply's are topical and interesting, they are not relevant to the subject, and would be better suited to a separate discussion.

Can anyone else assist?

 

[Skogsgurra]

Yes, you are right if you do not care about what your measurements are used for and if it is meaningful to do the measurements.

But, since this is engineering tips, and engineering is a lot more than reading an instrument, I think that we are on topic.

The whole "business" that has developped around the unfounded and ininformed fear that magnetic fields has health effects is bordering to being criminal. And I think that it is correct to point that out.

There are many "non human fear" reasons to measure magnetic field strength and I can recommend the FW Bell systems for technical measurements on magnet systems. They are in business for decades and are still developping their equipment. You may also look at DC magnetometers made by AlphaLab, Inc., in Salt Lake City and a lot of other manufacturers found by googling the right keywords. For extreme sensitivity, I have used flux gates from SCL in UK.



Gunnar Englund

http://www.gke.org