Electricity and water (pipes) DO mix
Summary: In older homes with metal pipes, the household electrical system may be grounded to a pipe. When the pipes are replaced with modern plastic piping, the electrical system MUST be properly regrounded - NOT to a plastic pipe.
The article below is reprinted with permission from BLUEPRINTS, a newsletter of the City of Bellevue Building Division. Thanks are due to Max Clark, editor of BLUEPRINTS, and Fred C. Volkers, Plumbing Inspector, the author of the article.
This article is intended to inform the public of a danger that could easily be overlooked and prove to be lethal. We know plumbing systems within buildings can wear out. We especially see this in water piping installed over the past 50 or more years. When a water system wears out it must be replaced, and the Uniform Plumbing Code (UPC) requires a building permit to be obtained and the system to be inspected to insure that the piping has been properly installed. Washington state law requires that the installation be done by either the homeowner or a state of Washington certified Journeyman Plumber.
Section 604.8 of the Uniform Plumbing Code states the following: "Approved plastic materials may be used in water service piping, provided that where metal water service piping is used for electrical grounding purposes, replacement piping shall therefore be of like material." The exception to this is "where a grounding system acceptable to the Administrative Authority is installed, inspected and approved, metallic pipe may be replaced with non-metallic pipe." Now you are probably saying "that is an electrical problem; why should I have to worry about it; I'm not an electrician; I'm a plumber or a homeowner." Well, for one thing, the previously quoted section of the code makes the person installing the new water piping responsible. Electrocution or electrical shock caused by a faulty grounding system can be FATAL.
Five times over the past few weeks City of Bellevue inspectors have inspected water service replacements and/or complete water system replacements where the plumber or homeowner has eliminated the ground for a home's electrical system. Most electric cords and electrical systems have three wires: one wire carries the power, one wire is the neutral, and one wire is the ground. The power wire carries the electricity to the electrically operated item or appliance, and the neutral carries the power back to the source through the electrical system. The ground has the potential to carry the current, when the neutral has been interrupted or the power wire comes in contact with appliance housing. The National Electric Code (NEC) defines grounded as: "Connected to earth or to some conducting body that serves in place of the earth." In order to protect yourself, you need to understand that electricity, like water, follows the path of least resistance. In other words, if it is easier for the power to go through you to ground, rather than through the neutral wire or ground wire, that is where it will go.
The NEC has always recognized the utilization of the metallic water service as one of the primary grounding electrodes. Every home and building with metallic water piping should have a ground wire leading from the panel to a metallic water pipe. Homes built prior to approximately 1960 used the metallic water pipe as the primary grounding electrode. After this time the NEC started requiring homes and buildings to have a ground rod (an 8-foot metal rod driven into the earth) installed along with the connection to the metallic water pipe. After approximately 1988, with the advent of non-metallic water systems in homes, the NEC required two ground rods to be installed as the primary grounding electrodes. The NEC still requires the electrical system to be grounded, and the metallic water pipe may be one of the primary electrodes. The metallic water system must also be bonded to the electrical system. Bonding includes the connecting of the hot and cold water pipe to each other with a properly sized copper wire. Bonding must also occur across any dielectric union, pressure reducing valve, D.C.V.A., R.P.B.A., and any valve or appurtenance that can be removed.
As previously noted, UPC Section 604.8 requires the plumber to maintain the electrical grounding system. In some situations this means you must merely reattach the grounding clamps to the new metallic water system. In other cases it means that a minimum of ten feet of metallic pipe must be buried in the earth between the end of the non-metallic water service and the new water system within the building. In cases where there is a non-metallic water service and non-metallic interior piping, the grounding system must be updated per the NEC Sections 250-50, 250-52 c (2&3) by a licensed electrician. In recent weeks we have talked to plumbers who have told us that they have done numerous water system replacements without confirming that the grounding system has been maintained. Without a properly maintained grounding system there is the potential that the electrical safety devices, breakers, or fuses will not do their job. The liability in these instances, per the UPC, would belong to the person who worked on the plumbing system, be it plumber or homeowner.
We hope this article generates awareness about a dangerous situation. In closing, if you have had your water system replaced and a permit was not obtained for any reason, we suggest a thorough check be made to assure that the electrical grounding system is still intact. If there is any doubt as to whether the electrical grounding system has been maintained or needs to be updated, an electrical contractor should be contacted.
Fred C. Volkers
This reprinted article is intended for informational use only and cannot be used as a substitute for the City of Kirkland Code. To obtain further information, please visit or call the Building Division (425-587-3600) between 8 a.m. and 5 p.m., Monday through Friday.
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