Grounding to plumbing

[Flambo]

I am employed in the drinking water utility and often encounter household corrosion issues that may be caused by grounding of electrical systems to the home plumbing. In older homes that have lead pipes or lead solder in the copper pipes, lead leaching from plumbing has resulted from such grounding. I have been told that this sort of grounding is part of the electrical code. This may be a case where the regulations of one utility may be causing harm to another. How do we, as a water utility, petition the electrical construction people to get this code changed?

 

[haskindm]

Grounding (actually bonding) to plumbing pipes will not in itself cause corrosion. Assuming you are referring to galvanic corrosion, it may be caused by current flowing through the pipes or from the natural current flow that is caused by dissimilar metals being immersed in an electrolyte (water that is less than 100% pure - see the thread on water as a conductor). The dissimilar metals is a hard problem to fix and this problem will exist whether or not the pipes are bonded to the electrical system. The current flow is from improper wiring is relatively easy. If there are improper ground to neutral connections in the building, neutral current will flow on the grounding conductors including the metal water pipes. This is corrected by removing the improper connections. The reduction of corrosion would not be sufficient reason to NOT bond the metal water lines in a building. Unbonded waterlines may become energized with no return path to clear the fault, which would be a dangerous and potentially deadly condition.
I think you are trying to find an easy solution for a difficult problem. Metal waterlines MUST be bonded, end of story, no exceptions. You will need to look for other ways to reduce the effects of corrosion. This section of the code cannot be changed.
The prevention of galvanic corrosion is a science and industry unto itself, ask anyone that operates a boat in salt water.

 

[jtester]

AC currents don't cause galvanic action, that is a dc function. Normal 60 hz currents have no effect, but if there is also dc on something, bonding all the piping together just exposes all systems to the dc currents.

Jim T