Originally Posted By: bmargiotti This post was automatically imported from our archived forum.
greetings,
a recent home inspection with the seller present invited a small discussion regarding grounding electrodes. i noted that there was no grounding rod to the buyer and the seller interrupted saying, “Oh, you dont need one, its grounded to the water pipes.” now i know the water pipe cant be the sole electrode, but more times than not i dont see a rod on old (50+ yrs) homes. are you all recommending that an electrician come and install one?
Originally Posted By: bking This post was automatically imported from our archived forum.
I always recommend a rod because water pipes get changed to plastic sometimes.
Metal water pipes should still be bonded to the system ground.
When water heaters get replaced with plastic stubs to the copper then you also need both hot and cold pipes bonded to the grounding system.
Originally Posted By: bbadger This post was automatically imported from our archived forum.
The NEC.
Quote:
250.53 Grounding Electrode System Installation.
(D) Metal Underground Water Pipe. Where used as a grounding electrode, metal underground water pipe shall meet the requirements of 250.53(D)(1) and (D)(2).
(2) Supplemental Electrode Required. A metal underground water pipe shall be supplemented by an additional electrode of a type specified in 250.52(A)(2) through (A)(7). Where the supplemental electrode is a rod, pipe, or plate type, it shall comply with 250.56. The supplemental electrode shall be permitted to be bonded to the grounding electrode conductor, the grounded service-entrance conductor, the nonflexible grounded service raceway, or any grounded service enclosure.
Exception: The supplemental electrode shall be permitted to be bonded to the interior metal water piping at any convenient point as covered in 250.52(A)(1), Exception.
I do not know how long this has been in the NEC at least a few code cycles.
Originally Posted By: russell r. This post was automatically imported from our archived forum.
Lots of older homes around here,and other areas where I work have either Copper,or Galvanized Steel water Service Lines,and this is the only grounding Electrode used.
My question would be,if it's determined that the Water Service is indeed Copper or galvanized,and there's at least 20 or 30 ft in the ground,how much good would it do to drive 2 ground rods?
Originally Posted By: Greg Fretwell This post was automatically imported from our archived forum.
The supplimental electrode requirement happened sometime between 90 and 75 but I don’t have those books. 75 just says you need a supplimental electrode if the pipe is continious for less than 10 feet or likely to become compromised
Originally Posted By: pbolliger This post was automatically imported from our archived forum.
In the city of Chicago, older buildings, I have rarely ever seen a grounding rod in homes. We have a water pipe grounding systems with a tag that states a city “article” number for people not to remove it… Newer construction I see some rods but there are plenty of old homes using water pipes…
Originally Posted By: russell r. This post was automatically imported from our archived forum.
My question would still be,If there’s several ft of metallic Water service line being used as a grounding Electrode,what do you fix or Upgrade by adding a driven ground rod? Other than making a 1950’s home comply with present Code Standards? Have you offered the Customer $200( or what ever the cost to add the ground Rods is) more lightning protection?
Well,it coulda been like I saw one several years ago. Plumber had replaced the Service Line with PVC,and had dutifully put the ground clamp back on the PVC line. 
Originally Posted By: dduffy This post was automatically imported from our archived forum.
Russell,
I have not seen a mess like today in a long time. The old KT was upgraded to Zinsco's at sometime in the past. All the galvanized water lines were cut and PVC installed all the way to the water meters.
Every wire in those boxes in the previous pictures were Hot except the two coming from the top of the one box.
40 volts of electricity back feeding out of the transformers attached to some panels, how I don't have a clue, leading to cut wires in the soffits.
My electricians will be there all day tomorrow finishing their report, before I can do the the entire report for the property.
It is a wonder the buildings have not burned down Yet... 