Split bolts to GEC / Sizing water meter bond?

[bill@enleyelectric.com]

Good Morning,

I have a job that we are finishing up and ran into some trouble on my rough inspection. We have a mixed use old bldg (major university dorm/frat house area where all of the frat houses are old brown stones converted) that will be 8 studio apartments, a 3 br apartment and various meeting rooms / commercial kitchen / worship area.... I have dual 600 amp services; one single phase for the meter stack feeding the apartments and the other 3 phase serving all house loads and the commercial kitchen.
The plans called for a 3/0 GEC which we took continuosly from the cabinet of the single phase meter stack breaker, into our 3 phase CT cabinet where we lugged it to the 3 phase service neutral out of there to a 10' 3/4" rod, up to the top of the room where we lugged it to bldg steel, and then to the 2" copper water line at its point of entry to the bldg where we ended it in a water pipe clamp listed for such.
Two things: As the GEC traveled through our electrical room we bonded all of the cabinets/troughs to the GEC with the appropriatley sized conductor based on largest ungrounded conductor in that particular cabinet or trough (i believe 250.166 but im not in front of my code book), to teminate at the GEC we used split bolt connectors to attach to the unbroken GEC. My inspector wants those connections to be weld or crimp (is that correct??

He also wants me to crimp onto/extend the GEC at the incoming water service and then instead of ending the GEC at the water pipe, he wants me to extend it in its unbroken (now continuous crimped) length across the water meter/backflow preventer and then leave enough 3/0 so that when the gas equipment/meter is installed we can bold across that with this GEC also. Does this seem right? We did have the water meter bonded/jumpered indepently from the GEC. Is that jumper also sized according to the GEC size that he is requesting?:?

I love this forum, ive been a member for a long time and dont post much but read often.

 

[Smart $]

...
Two things: As the GEC traveled through our electrical room we bonded all of the cabinets/troughs to the GEC with the appropriatley sized conductor based on largest ungrounded conductor in that particular cabinet or trough (i believe 250.166 [250.122] but im not in front of my code book), to teminate at the GEC we used split bolt connectors to attach to the unbroken GEC. My inspector wants those connections to be weld or crimp (is that correct??

Equipment Bonding Jumpers are not required to be irreversibly spliced.

He also wants me to crimp onto/extend the GEC at the incoming water service and then instead of ending the GEC at the water pipe, he wants me to extend it in its unbroken (now continuous crimped) length across the water meter/backflow preventer and then leave enough 3/0 so that when the gas equipment/meter is installed we can bold across that with this GEC also. Does this seem right? We did have the water meter bonded/jumpered indepently from the GEC. Is that jumper also sized according to the GEC size that he is requesting?:?.

Bonding of the water piping system, making the system continuous from GEC attachment, the jumpers are sized per 250.66 in most cases, especially when bonded to the service. Irreversible splicing not required. You could even use a second clamp by the GEC clamp. There are provisions for bonding in multi-dwelling to non-service panels using jumpers sized per 250.122, but that doesn't sound like you situation. Bonding of other metal piping systems (gas) is sized per 250.122 using the largest rating of circuits likely to energized. This is commonly handled by bonding the EGC of the circuit likely to energize the pipe at the utilization outlet... but can be done as inspector "suggests".

 

[bill@enleyelectric.com]

Thank you for the reply smart$.

When sizing the bonding jumper for the water meter as per the table 250.122 i dont quite understand the way I am sizing based on the setting of the overcurrent device likely to energize the piping. It looks that for me to have to bond the water piping with 3/0 copper, the rating or setting of the overcurrent device would have to be 1200 amps? Am I way out in left field on this? If I am to use this table, should I be basing my size on the full incoming 600 amp service disconnect?

In my first post, I neglected to include the fact that we also bonded each gas tite run from the manifold across its compression nut (as per mftr bulletin) and back to the GEC with a #6 copper and split bolt. Thats why Im a little confused as to why i now need to jumper the gas meter with a full 3/0. The gas manifold is only a few feet from where the gas valve and meter is located.

 

[Smart $]

When sizing the bonding jumper for the water meter as per the table 250.122 i dont quite understand the way I am sizing based on the setting of the overcurrent device likely to energize the piping. It looks that for me to have to bond the water piping with 3/0 copper, the rating or setting of the overcurrent device would have to be 1200 amps? Am I way out in left field on this? If I am to use this table, should I be basing my size on the full incoming 600 amp service disconnect?

The bonding jumper to the metal water piping system is sized per 250.66, for the manner in which you are bonding (jumpering across the water meter from your street-side GEC connection). Bonding jumpers from subpanels in multidwelling buildings is the only time you are permitted to size per 250.122.

In my first post, I neglected to include the fact that we also bonded each gas tite run from the manifold across its compression nut (as per mftr bulletin) and back to the GEC with a #6 copper and split bolt. Thats why Im a little confused as to why i now need to jumper the gas meter with a full 3/0. The gas manifold is only a few feet from where the gas valve and meter is located.

Here's the relevant subsection of 250.104 from the 2011 NEC...

(B) Other Metal Piping. If installed in, or attached to, a
building or structure, a metal piping system(s), including
gas piping, that is likely to become energized shall be
bonded to the service equipment enclosure; the grounded
conductor at the service; the grounding electrode conductor,
if of sufficient size; or to one or more grounding electrodes
used. The bonding conductor(s) or jumper(s) shall be
sized in accordance with 250.122, using the rating of the
circuit that is likely to energize the piping system(s). The
equipment grounding conductor for the circuit that is likely
to energize the piping shall be permitted to serve as the
bonding means. The points of attachment of the bonding
jumper(s) shall be accessible.

Informational Note No. 1: Bonding all piping and metal​

air ducts within the premises will provide additional safety.

​

Informational Note No. 2: Additional information for gas​

piping systems can be found in Section 7.13 of NFPA 54-​

2009, National Fuel Gas Code.​