Effect of Grounding and electrical properties ON WATER QUALITY

Abstract

For many years, the water utility industry has had concerns about the effect of grounding currents on water quality. Early research on the subject included studies that focused primarily on grounding's effects on water quality in terms of

Issues associated with use of dielectrics in drinking water systems

“…Use of water pipes for electrical grounding has long been a controversial subject (Duranceau et al, 1998; Horton, 1995; Carlton, 1974), and there have been well‐documented cases of service line failure because of external corrosion, electrocution of utility employees, and evidence of excessive metal leaching to potable water in at least some plumbing configurations (Bell & Duranceau, 2002; Duranceau et al, 1998; Horton, 1995; Carlton, 1974). In cases in which a service line carries stray current from a miswired electrical system, a dielectric could reduce the risk of electrocution to utility employees.…”

“…Some current building construction codes require that electrically continuous metallic water lines extend at least 3 m ( ≈ 10 ft) from the structure if they are to be used as an effective grounding electrode for homes (ICC, 2011a). Other studies indicated that dielectrics will reduce stray currents flowing on pipes (Horton, 1995; Carlton, 1974), but it has also been shown that if stray currents are allowed to persist, use of a dielectric can contribute to excessive internal corrosion in at least some plumbing configurations (Holtsbaum, 2007; Bell & Duranceau, 2002).…”

“…Reduces lead or iron in water resulting from direct galvanic corrosion Can actually increase corrosion and metals in at least some cases if stray alternating/ direct currents are carried on pipes Bell & Duranceau, 2002;Holtsbaum, 2007;St. Clair et al, 2012 Deposition corrosion Deposition corrosion not controlled by dielectric Hu et al, 2012;Triantafyllidou & Edwards, 2010 Fe-iron, Pb-lead…”

“…Obviously, any potential benefit of preventing galvanic corrosion must be weighed against a more rapid localized attack of the iron mains at copper service line connections; however, no cost-benefit analysis of these tradeoffs has ever been conducted (Gehring et al, 2003;Rajani & Kleiner, 2003;O'Day, 1989). Finally, in at least some cases, installation of dielectrics on lines carrying alternating/direct stray currents can induce corrosion and cause ele-vated iron, lead, and copper in water (Bell & Duranceau, 2002;Horton, 1995). The use of a dielectric does not eliminate all issues related to galvanic corrosion.…”