grounding pipe at water heater even though all plastic water lines

[Stevenfyeager]

My instructor told me to run a separate ground from the panel to the metal fitting on top of the electric water heater even though this brand new animal clinic has all plastic water lines including the underground supply. He retired two months ago. I've roughed it in, was it necessary? Thank you.

 

[Smart $]

My instructor told me to run a separate ground from the panel to the metal fitting on top of the electric water heater even though this brand new animal clinic has all plastic water lines including the underground supply. He retired two months ago. I've roughed it in, was it necessary? Thank you.

Necessary? No... especially if it is an electric water heater.

Metal piping systems are required to be bonded if likely to become energized, but they are usually bonded through the EGC of electrical equipment from which they are likely to be energized from.

Additionally, where metal water piping is a qualified grounding electrode (not your particular case though), it gets bonded through the GEC and a jumper around metering equipment.