Many of the mixing manifolds are now nonmetallic and even if they are metallic they are often connected to the metal water piping system using a nonmetallic flex connector.When the cold water is bonded, the hot water is also thru every mixing manifold in the building.
Many water heaters have a dielectric fitting to isolate the tank from the water piping system.The water heater tank itself provides this connection between the two.
Unless these mixing manifold/bonding jumpers are listed for the purpose of bonding, wouldn't relying on them be a violation of 250.8?Originally posted by roger:
When the cold water is bonded, the hot water is also thru every mixing manifold in the building...
Roger
Originally posted by roger:
Eprice, using that reasoning we would have to provide a jumper around every copper coupling that was soldered. But I'm still not convinced. The NEC and everyone else has accepted the concept that joints in recognized metal piping systems provide electrical continuity (despite the solder). I guess questions might be, is the mixing manifold part of the piping system, or is it a connection between two separate sections of the piping system? Will internal gaskets etc. intefere with fault current flow?
You stated earlier that if we know there is a complete isolation of the piping system there would need to be a connection. I'd rather say, if we don't know for sure that there isn't an isolation we need to make an intentional bond.
I guess it's another area of the code that is open to differing interpretations. In my neck of the woods bonding hot to cold just seems to be the accepted practice.