Thread: Nec 250.32 question

If a separate building or structure is required to have a grounding electrode Nec 250.32, why do swimming pool panels not have a separate electrode?

Always something to be learned here - - - I have never seen an electrical panel that could swim. I am no pool expert, but believe they have a defacto grounding electrode via the extensive bonding of all the potential current carrying components in a pool, ( rebar, mesh, code required copper conductor grid, conductive scupper or lighting and anything requiring power ).

Originally Posted by Garry Blankenship

Always something to be learned here - - - I have never seen an electrical panel that could swim. I am no pool expert, but believe they have a defacto grounding electrode via the extensive bonding of all the potential current carrying components in a pool, ( rebar, mesh, code required copper conductor grid, conductive scupper or lighting and anything requiring power ).

I see..., but under NEC: Structure: That which is built or constructed.
Such as a pool. AFA equipotential bonding, I assumed that was something different and separate.
I was just wondering about the need for a grounding electrode for separate structure. Hopefully, this isnt a stupid question, but Im sure I will find out here real quick.

Originally Posted by Robert Meier

Yes a separate structure requires a GES or grounding electrode system. If the supply is a single circuit or a MWBC then the GES is not required. In the case of a pool panel it's not the pool that is the separate structure but the structure built to hold the panel.

Not taking any issue with the above, but curious, ( a question ), wouldn't the extensive bonded ground grid in a pool qualify as a GES and hence be a defacto GES or grounding electrode ?

Originally Posted by Garry Blankenship

Not taking any issue with the above, but curious, ( a question ), wouldn't the extensive bonded ground grid in a pool qualify as a GES and hence be a defacto GES or grounding electrode ?

Thanks Robert. So in the case of the panel, then no It does not require such a GE.
Garry you raised a pretty darn good point.

Originally Posted by Robert Meier

In the case of a pool panel it's not the pool that is the separate structure but the structure built to hold the panel.

The structure which holds the pool panel is typically the same structure as that which supplies the pool - the house.

The pool is a separate structure and is one giant (for concrete pools) concrete encased electrode, however, the pool is not used as such, the pool steel is bonded to the the pool perimeter bonding ring, the pool pump, the pool heat pump, etc.

The intent is that if the water in the pool becomes energized, then all things associated with the pool and within 5 feet of the pool are also energized the same as the pool water, thus no shock. While the pool is a giant concrete encased electrode, nothing has -0- resistance and any current through any resistance creates a voltage drop across that resistance, thus there could be a voltage different from ground (earth) even though the pool is one giant concrete encased electrode.

Now, taking that a step further, if the pool is a giant concrete encased electrode and IT is not -0- resistance to ground (earth), then it is easy to understand that a concrete encased electrode would have even higher resistance to ground (earth) and why a simple ground rod makes a poor grounding electrode.

Because the entirety follows strict bonding rules, including the equipotental grid, equipment, water, from the feeder source equipment grounding conductor.See Section 680, see esp.680.3, 680.6 (680.6 Number (7)), 680.21(A)(4), 680.21(B), all of 680.25 (Feeders) & 680.26 of your 2010 California Electrical Code (also IIRC, you're nearly -- if not entirely -- 100% service laterals with risers to exterior serivce equipment).

Originally Posted by H.G. Watson, Sr.

Because the entirety follows strict bonding rules, including the equipotental grid, equipment, water, from the feeder source equipment grounding conductor.See Section 680, see esp.680.3, 680.6 (680.6 Number (7)), 680.21(A)(4), 680.21(B), all of 680.25 (Feeders) & 680.26 of your 2010 California Electrical Code (also IIRC, you're nearly -- if not entirely -- 100% service laterals with risers to exterior serivce equipment).

I'm feeling confident you made a point in there, but I missed it. My best guess is you're saying it is basically a separate service , (?). Could you maybe drop all the code article citations and give it to me in lay terms ?