Q. An equipotential plane installed at a catfish farm pond is required for the service equipment installed outdoors (adjacent to the pond), where the service equipment controls equipment is installed in and adjacent to the water. This equipotential plane shall consist of a minimum size ______ copper conductor, installed ________, and extended out a distance of at least ______ in all directions from the equipment.
A) No. 8 solid / a minimum of 3 inches beneath or embedded in the walk surface / 36 inches
B) No. 8 stranded / a minimum of 3inches beneath or embedded in the walk surface / 36 inches
C) No. 6 solid / 24 inches beneath the service entrance equipment / 42 inches
D) No. 4 solid / no requirement / 48 inches
Explanation: A new article was added to the 2005 NEC covering electrical wiring and equipment in or adjacent to bodies of waters. Section 682.33 of Article 682, Natural and Artificially Made Bodies of Water, requires an equipotential plane (ground grid) beneath and extending out 36 inches in all directions of service equipment and disconnecting means operated by personnel, where the disconnecting means and/or service equipment is used to control equipment in or on the water. In addition, Section 682.2 establishes a minimum 3-inch depth or embedment in the walk surface.
The requirements of this section are similar to the requirements in Section 680.26 for the grounding and bonding of swimming pools.
Owen is the owner and president of National Code Seminars and the holder of master electrician certifications in 46 states. He can be reached at [email protected].