A model for characterizing residential ground current and magnetic field fluctuations

Mader, David; Peralta, S. B.; Sherar, Michael D.

doi:10.1002/bem.2250150109

Cited by 3 publications

(2 citation statements)

References 8 publications

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“…In addition to the 1,000-Home Study, the relationship between residential magnetic fields and features of the residential and neighborhood grounding systems has been addressed in several other studies, using both measurements and modeling (Kavet et al 2006;Mader et al 1990Mader et al , 1994Zaffanella et al 1997). A more thorough analysis of 333 1,000-Home Study residences, restricted to the two lowest Wertheimer-Leeper wire code categories (see Kheifets et al 1997 for wire code description) to minimize power line effects, reported that in decreasing order, ground current, number of service drops on the transformer serving the residence, residence age, and location (urban, suburban, rural) influenced the residential magnetic field.…”

Section: Discussionmentioning

confidence: 97%

Residential Magnetic Fields and Measures of Neutral-to-Earth Voltage: Variability Within and Between Residences

Kavet¹,

Hooper

2009

Health Physics

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The objectives of this study were to characterize temporal patterns of magnetic fields (Bavg) and two measures of neutral-to-earth voltage: the voltage between the water line and earth (VW-E), and the voltage between bathtub plumbing fixtures and the drain (Vbath). The latter is a source of exposure to contact current in bathing children that has been proposed to explain the reported association between power-frequency magnetic fields and childhood leukemia. These quantities were measured each minute in a sample of 15 single-detached residences in San Jose, CA. Generally, Bavg, VW-E, and Vbath were positively correlated with each other within residences, and displayed similar diurnal patterns. Weekday and weekend patterns displayed qualitative differences that reflect the more scheduled workday for weekdays, and a less structured pattern for weekends. When pooled with two prior measurement studies, positive associations across residences between Bavg and both VW-E and Vbath were observed. Home designs over the past 30-40 years have lead to a decreasing prevalence of Vbath as conductive drains have been swapped out for non-conductive materials. Nonetheless, the observed relationships within and across residences indicate that contact current has the characteristics of a factor that could explain the association of magnetic fields with childhood leukemia.

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Section: Discussionmentioning

confidence: 97%

Residential Magnetic Fields and Measures of Neutral-to-Earth Voltage: Variability Within and Between Residences

Kavet¹,

Hooper

2009

Health Physics

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“…The report concluded that net currents from the medium-voltage distribution system are a common source of residential fields and that their contribution can usually be assessed with reasonable accuracy from outside the residence. Mader et al (1994) produced a model for characterising ground current and magnetic field fluctuations within the curtilage of US homes. Ground currents are caused by a non-balanced system arising from the use of appliances within the home.…”

Section: Introductionmentioning

confidence: 99%

The contribution of local distribution substations and associated area distribution system to personal exposure to power frequency magnetic fields

Grainger

Preece

2000

International Journal of Environmental Health Research

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A number of epidemiological studies has shown a significant correlation between wire coding, magnetic fields and childhood cancer, although a more recent study has not [McBride et al. (1999) Am. J. Epidemiol. 149 (9), 831-842]. In the UK there is currently no equivalent to wire-codes and there is some uncertainty about the extent to which the UK medium-voltage electricity distribution systems contribute to personal exposure and how this compares with US overhead supply systems. Studies on four different area types were carried out to measure magnetic field intensities from typical electricity supply utility substations and cabling in the vicinity of domestic housing. Typically at distances of two metres from the substations mean magnetic field intensities were 20 nano teslas (nT) or less, increasing to 0.98 microT or less at the closest public access point. The mean magnetic field exposure level sampled around the four main test areas varied between 0.012 and 0.27 microT increasing to 0.30-0.80 microT at road junctions.

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Study of magnetic fields from power-frequency current on water lines

Lanera

Zapotosky

Colby

1997

Bioelectromagnetics

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The magnetic fields from power‐frequency current flowing on water lines were investigated in a new approach that involved an area‐wide survey in a small town. Magnetic fields were measured outside the residence under power cables and over water lines, and each residence was characterized as to whether it received water from a private well or the municipal water system. The magnetic field data revealed two statistical modes when they were related to water supply type. The data also showed that in the case of the high mode, the magnetic field remained constant along the line formed by power drop wires, at the back of the house, and the water hookup service, in front of the house, all the way to the street. The patterns are explained by the coincidence of measurement points and the presence of net current flowing on power mains, power drop conductors, residential plumbing, water service hookups, and water mains. These patterns, together with other characteristics of this magnetic field source, such as the gradual spatial fall‐off of this field and the presence of a constant component in the time sequence, portray a magnetic field more uniform and constant in the residential environment than has been thought to exist. Such characteristics make up for the weakness of the source and make net current a significant source of exposure in the lives of individuals around the house, when human exposure to magnetic fields is assumed to be a cumulative effect over time. This, together with the bimodal statistical distribution of the residential magnetic field (related to water supply type), presents opportunities for retrospective epidemiological analysis. Water line type and its ability to conduct power‐frequency current can be used as the historical marker for a bimodal exposure inference, as Wertheimer et al. have shown. Bioelectromagnetics 18:307–316, 1997. © 1997 Wiley‐Liss, Inc.

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A model for characterizing residential ground current and magnetic field fluctuations

Cited by 3 publications

References 8 publications

Residential Magnetic Fields and Measures of Neutral-to-Earth Voltage: Variability Within and Between Residences

Residential Magnetic Fields and Measures of Neutral-to-Earth Voltage: Variability Within and Between Residences

The contribution of local distribution substations and associated area distribution system to personal exposure to power frequency magnetic fields

Study of magnetic fields from power-frequency current on water lines

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