Jack tells us: In an existing commercieal pool we are adding a diving board. Board will be supported by ancor bolts expoxyed to the existing deck. Support for the board is concrete, does the rebar and support bolts in this addition require connection to the existing equipotential system?
Thank you for your question regarding swimming pool grounding, it is our pleasure to help.
Yes, you must bond all of the rebar and support bolts in to the equipotential ground system. In fact, Article 680.26 (7) requires you to bond all the rebar within 5-ft of the pool wall, including the sidewalk. The National Electrical Code (NEC) is quite clear on this subject. We recommend the NEC 2011 Handbook and McGraw-Hill’s National Electrical Code 2011 Handbook for reference. In particular you may want to look at Article 280.26 and Exhibit 680.8. The Exhibit in particular specifically shows the diving board and the mounting plate for it being bonded to the equipotential grounding plane.
Just a quick reminder, you are required to have two (2) grounding systems for swimming pools: the “green wire” ground, and an additional bare copper equipotential ground system. The “green wire” ground is only designed to ensure that circuit breakers and other Over Current Protection Devices (OCPD) operate properly. The equipotential grounding system is designed to reduce the formation of life-threatening voltages that can form in the pool. We talk about these voltages all the time on our blog, however we discuss them in their technical terms: Step & Touch Voltage hazards, Ground Potential Ride (GPR, and Ground Potential Difference (GPD). Please feel free to go through our blog, there is a lot of material on these subject matters.
We hope you find this useful, if you should have any further questions, please do not hesitate to call us at 310-318-7151 California time.
The Engineering Team at E&S Grounding Solutions