Any piece of metal connected to the electrical system, intentionally or unintentionally, will carry some current.
There is no way to stop it.
I totally agree. I was taught to bond the hot and cold and believe its required in the gray area of the code and here is my 2 cents worth.
Anything conductive thats connected to an electrical system had the potential of becoming energized hence it must be or grounded or bonded. The cold water side of a water heater on an all metal plumbing system. My problem with not bonding is most waters have dielectric fittings to prevent electrolysis between the copper pipes and iron tank. They are also insulates the hot side of the plumbing from the cold side. There could be a conductive connection between the hot and cold lines at faucets where they mix together but how can we be sure that's an adequate conductive path with the use of more and more plastic parts used in faucets and Teflon tape? If the hot side becomes energized some how, if there is not a sufficient pathway between the hot and cold lines, there will be potential voltage between the two and we all know what will happen if both are touched at the same time like reach under the sink of shutting off both faucets. More and more plastic parts. As electricians we have to ensure that anything that is likely to become energized must be effectively bonded.
I started to research this in greater detail years ago because of the confusion. I have PE's arguing its a must to bond and other going no way. Maybe I need to continue this research...
