Thread: Grounding to water supply from feeder panel

Is it permitted to run a ground wire to the water supply pipe from the feeder panel ground terminals instead of from the main panel? In this installation the grounding electrode was run from the main panel, but the ground to the water supply pipe was run from the feeder panel.

The grounding needs to come from the service panel.

Originally Posted by Jim Port

The grounding needs to come from the service panel.

Thanks. That is what I have always through, but I saw grounds originating at feeder panels in two newer houses recently and started to question whether this was correct.

I would need to look it up to be sure, but bonding of the interior water piping system may not be required to be directly bonded to the service equipment as bonding to the groundING conductor in a remote panel bonds the metal water piping back to the service equipment to.

Jim P what say you? I can look it up later.

I have never done it that way and don't know whether it would fly or not. Jack D would know

Originally Posted by Jim Port

I have never done it that way and don't know whether it would fly or not. Jack D would know

I just got back to my office and looked it up, the answer is yes and no ... sort of.

From the 2008 NEC (on my computer for easy copy and paste): (bold and underlining are mine)
- 250.104 Bonding of Piping Systems and Exposed Structural Steel.
- - (A) Metal Water Piping. The metal water piping system shall be bonded as required in (A)(1), (A)(2), or (A)(3) of this section. The bonding jumper(s) shall be installed in accordance with 250.64(A), (B), and (E). The points of attachment of the bonding jumper(s) shall be accessible.
- - - (1) General. Metal water piping system(s) installed in or attached to a building or structure shall be bonded to the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor where of sufficient size, or to the one or more grounding electrodes used. The bonding jumper(s) shall be sized in accordance with Table 250.66 except as permitted in 250.104(A)(2) and (A)(3).
- - - (2) Buildings of Multiple Occupancy. (basically not applicable to houses)
- - - (3) Multiple Buildings or Structures Supplied by a Feeder(s) or Branch Circuit(s). (not likely applicable to most houses in most cases)

If the grounding conductor to a remote panel met the requirements of 250.104(A)(1), then I can see that being permitted as the bonding jumper (for a potential 'yes' answer), otherwise the answer would be 'no, needs to be bonded at the service equipment'.

Yo JP,
Just to clarify and for the record, not trying to be flippant...by bonding the panels downstream to the SEP (which connect to the SEP), "technically" bonds the water piping by proxy?

Originally Posted by Jerry Peck

I just got back to my office and looked it up, the answer is yes and no ... sort of.

From the 2008 NEC (on my computer for easy copy and paste): (bold and underlining are mine)
- 250.104 Bonding of Piping Systems and Exposed Structural Steel.
- - (A) Metal Water Piping. The metal water piping system shall be bonded as required in (A)(1), (A)(2), or (A)(3) of this section. The bonding jumper(s) shall be installed in accordance with 250.64(A), (B), and (E). The points of attachment of the bonding jumper(s) shall be accessible.
- - - (1) General. Metal water piping system(s) installed in or attached to a building or structure shall be bonded to the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor where of sufficient size, or to the one or more grounding electrodes used. The bonding jumper(s) shall be sized in accordance with Table 250.66 except as permitted in 250.104(A)(2) and (A)(3).
- - - (2) Buildings of Multiple Occupancy. (basically not applicable to houses)
- - - (3) Multiple Buildings or Structures Supplied by a Feeder(s) or Branch Circuit(s). (not likely applicable to most houses in most cases)

If the grounding conductor to a remote panel met the requirements of 250.104(A)(1), then I can see that being permitted as the bonding jumper (for a potential 'yes' answer), otherwise the answer would be 'no, needs to be bonded at the service equipment'.

Originally Posted by Marc M

Yo JP,
Just to clarify and for the record, not trying to be flippant...by bonding the panels downstream to the SEPtechnicalitconnect to the SEP[/I]), "technically" bonds the water piping by proxy?

Marc,

I will rephrase the above: bonding to downstream panels may bond the metal water piping back to the service equipment by proxy, but ... "technically" ... it does not bond the metal water piping back to the service equipment unless the bonding conductor meets the requirements for the bonding conductor.

It may accidentally bond it to the service equipment by proxy ... but I would not like to rely on accidents happening at the precise time the accident needs to happen.