#750: Ground Current in Rural and Urban Areas
From Magda Havas
Read the Star article and two abstracts below.
Ground Current in Ontario:
Thought you might be interested in this article on what Ontario is doing about Ground Current problems.
The 10 volts currently used in Ontario is as ridiculous as the 833 mG used for magnetic fields and the 1000 microW/cm2 used for radio frequency radiation. None of these guidelines is protective.
It is my hope that Ontario will NOT limit its guideline to 0.5 volts (500 millivolts), which is for 60 Hz frequencies, but instead will recognize that higher frequencies (kHz), recognized as dirty power, have to be even lower.
Dr. Don Hillman has regularly shown that 10 millivolts peak to peak of dirty power causes a problem for dairy cows. So there are at least two issues here that relate to two different frequency ranges: 60 Hz and higher frequencies in the KHz and possibly MHz range.
Some ground current “experts” measure ONLY the 60 Hz frequency and this does not always relate to cow problems. Cows react to voltages lower than 0.5 volts and this often relates to the dirty power. Both 60 Hz and higher frequency ranges NEED to be measured to determine if there is a ground current problem in a particular area.
Dr. Martin Graham has designed a ubiquitous filter (NOTE: this is NOT the GS filter that has been used in homes and schools to reduce dirty electricity) that separates the 60 Hz voltage from the voltage associated with higher frequencies and this allows more accurate measurements on an oscilloscope.
People who work on ground current have to know what to measure and how, when and where to measure it. A small group is working on a protocol and a meter that will enable anyone to do their own measurements accurately without expensive monitoring equipment.
Ground Current in Urban Centres
And for those people who think that ground current is entirely a rural problem . . . think again. Ground current is present in some urban areas as well and enters homes via metal plumbing. Kavet has demonstrated in several of his publications that contact current (the current that flows through your body when you touch an object that is at a different potential) can be a serious issue in some homes and may explain the increased risk of childhood leukemia. Kavet concludes in his 2002 paper (see abstract below):
This correlation, combined with both frequent exposure opportunity for bathing children and substantial dose to bone marrow resulting from contact, lead us to suggest that contact current due to VW-E could explain the association between high residential magnetic fields and childhood leukemia.
Wertheimer et al. 1995 came to the same conclusion in an earlier paper. They found the odds ratio for childhood leukemia was highest in homes with conductive plumbing and a high magnetic field. The last line in this abstract reads:
The associations of cancer with conductive plumbing and with this exposure metric both suggest that cancer risk is increased among persons with elevated magnetic field exposure from residential ground currents.
The abstracts for both of these papers is below Tyler Hamilton’s article. Tyler does a great job in his article below.
-magda
Article 1
Please visit link: http://www.thestar.com/article/228188
Ontario to regulate electrical pollution
Watchdog’s new rules would cut stray currents
Jun 22, 2007 04:30 Am
Tyler Hamilton
ENERGY REPORTER,THE TORONTO STAR
Dairy cows literally shocked by stray voltage buzzing around rural farmlands could soon get some udder relief from Ontario’s energy watchdog.
Energy Minister Dwight Duncan is to ask the Ontario Energy Board today to impose stringent rules on electricity distribution utilities aimed at limiting occurrences of so-called ground current pollution.
It’s a phenomenon often referred to as “tingle voltage,” which is known to make dairy cows and other livestock sick.
Duncan will make the announcement today with Maria Van Bommel, Liberal MPP for Lambton-Kent-Middlesex, at a farm in the southern Ontario riding.
Bommel attempted to address the problem last year by introducing a private member’s bill called the Ground Current Pollution Act, which passed two readings but was eventually referred to a standing committee.
By asking the energy board to tackle the issue, Duncan has decided to bypass the need for new legislation, sources say.
Tingle voltage happens when aging distribution lines “” many designed to handle electricity demand during the 1950s “” can’t properly cope with the flow of electricity, particularly in rural areas facing population growth from new housing developments.
Neutral wires that are supposed to carry the return flow of electricity from a substation can’t handle the load.
That causes excess voltage to flow over the ground instead, on a path of least resistance. If the problem occurs near a farm, the voltage can get into barns, farm equipment, home plumbing, animals and even people.
Dairy cattle, because of their size, tend to be more vulnerable than most animals, and there is rising acceptance among veterinarians, academics and researchers that stray voltage can cause the udders of cows to become swollen and chronically infected, ultimately affecting milk production and farmers’ revenues.
Malformed calves and spontaneous abortions have also been observed. Cows will even become dehydrated because the simple act of drinking from a bowl can cause a shock.
One government source said the new rules will require distribution utilities in rural areas, predominantly Hydro One, to outline a plan of continual line improvement. “It’s all part of modernizing the distribution system, which has always been the poor cousin (of the transmission system).”
And cows wouldn’t be the only ones to benefit. Upgrades to the distribution system will also make it possible for more renewable energy projects based on wind, solar and biomass to connect to the grid. Old and overloaded distribution lines have limited the ability of some projects to move forward.
Daffyd Roderick, a spokesperson for Hydro One, which owns and controls a mostly rural distribution system that spans 75 per cent of the province, said the problem of tingle voltage isn’t unique to Ontario.
“If a farm identifies a tingle voltage issue, we will conduct an engineering investigation to confirm the existence of the problem,” he said.
Hydro One will fix the problem if it is responsible. “If it’s a customer problem, we’ll offer them advice on how to rectify the situation.”
New rules through the energy board, however, would likely force the company to be proactive rather than reactive to customer concerns. “As for an announcement that hasn’t yet been made,” Roderick said, “we can’t comment.”
Hydro One complies with the current stray-voltage limit of 10 volts set in Ontario, but the limit in several U.S. states is 20 times lower. The Ontario Federation of Agriculture has long argued that the limit in Ontario should be set at 0.5 volts.
Article 2
Childhood cancer in relation to indicators of magnetic fields from ground current sources.
Wertheimer N, Savitz DA, Leeper E
Bioelectromagnetics 1995; 16:86-96.
Abstract
This study examines childhood cancer risk in relation to certain factors likely to indicate magnetic field exposure from ground currents in the home. Substantial ground currents are most often found in homes having conductive plumbing, in which an uninterrupted metallic path in the water pipes and water main connects the grounding systems of neighboring houses. Information on plumbing conductivity was obtained from water suppliers for the homes of 347 cases and 277 controls identified in an earlier study of magnetic field exposure and childhood cancer in the Denver area. An increased cancer risk was observed for children in homes with conductive plumbing: The matched odds ratio was 1.72 (1.03-2.88) and increased to 3.00 (1.33-6.76) when analysis was limited to cases and controls who were residentially stable from the reference date to the study date. A measurement metric likely to indicate active ground currents (measurements having above-median intensity and a nonvertical orientation of < 55 degrees from the horizontal) was identified. In contrast to measured field intensity alone, for which only modest associations with cancer have been reported, this metric shows a high and significant cancer risk [matched O.R. = 4.0 (1.6-10.0)] consistent over a range of intensity and angle cutpoints. Such elevated nonvertical fields were also associated with cancer in an independent data set, which was gathered to study adult nonlymphocytic leukemia in the Seattle area. The associations of cancer with conductive plumbing and with this exposure metric both suggest that cancer risk is increased among persons with elevated magnetic field exposure from residential ground currents.
Article 3
Contact voltage measured in residences: Implications to the association between magnetic fields and childhood leukemia
Robert Kavet, Luciano E. Zaffanella
Bioelectromagnetics 2002; 23 (6):464-474.
Abstract
We measured magnetic fields and two sources of contact current in 36 homes in Pittsfield, MA. The first source, VP-W, is the voltage due to current in the grounding wire, which extends from the service panel neutral to the water service line. This voltage can cause contact current to flow upon simultaneous contact with a metallic part of the water system, such as the faucet, and the frame of an appliance, which is connected to the panel neutral through the equipment-grounding conductor. The second is VW-E, the voltage between the water pipe and earth, attributable to ground currents in the water system and magnetic induction from nearby power lines. In homes with conductive water systems and drains, VW-E can produce a voltage between the faucet and drain, which may produce contact current into an individual contacting the faucet while immersed in a bathtub. VP-W was not strongly correlated to the magnetic field (both log transformed) (r = 0.28; P < 0.1). On the other hand, VW-E was correlated to the residential magnetic field (both log transformed) (r = 0.54; P < 0.001), with the highest voltages occurring in homes near high voltage transmission lines, most likely due to magnetic induction on the grounding system. This correlation, combined with both frequent exposure opportunity for bathing children and substantial dose to bone marrow resulting from contact, lead us to suggest that contact current due to VW-E could explain the association between high residential magnetic fields and childhood leukemia.