Bonding to multiple lines / 250.104

[augie47]

Situation: One building, several,(15), occupancies, (1) Service, (15) metered feeders (one to each occupancy).
Each occupancy has a underground copper water line, separately metered, (each water meter underground, in front of occupancy)and its own electrical panel fed from the main service disconnect.
None of the water lines connect metallically within the structures, however, it is thought that the common waterline (utility) serving the water meters is metallic.

Can 250-104(B) be applied in this case?
If not, can the grounding electrode conductor be run to the one closest water line only?

[ December 08, 2005, 08:22 PM: Message edited by: augie47 ]

 

[websparky]

Re: Bonding to multiple lines / 250.104

Augie,

Let's say that there is not a water line that qualifies as a grounding electrode for the service but there are a couple of ground rods. This alone would satisfy code as far as electrodes.

In this case you could apply 250.104(A)(2) for each occupancy because (A) is for "water piping" and 250.104(B) is for "other metal piping".

 

[bphgravity]

Re: Bonding to multiple lines / 250.104

It seems as though you are combining issues here. To start with, the service needs to be grounded. If a metal underground water pipe meeting the specifications in 250.52(A)(1), that must be used as a grounding electrode.

Each of the isolated water pipe systems for each unit will need to be bonded in accordance with 250.104(A)(2).