Washington Administrative Code › Title 296 - Labor and Industries, Department of › Chapter 296-46B - Electrical safety standards, administration, and installation › Part A - NEC INSTALLATION AMENDMENTS, STANDARDS, INSPECTIONS, AND DEFINITIONS › Section 296-46B-250 - Grounding and bonding

Current through Register Vol. 24-14, July 15, 2024
028 (D)(3) Separately derived system with more than one
				  enclosure.
(1) NEC 250.28
				(D)(3) is amended to read: Where a separately derived system supplies more than
				a single enclosure, the system bonding jumper for each enclosure shall be sized
				in accordance with 250.28 (D)(1) based on the largest ungrounded feeder/tap
				conductor serving that enclosure, or a single system bonding jumper shall be
				installed at the source and sized in accordance with 250.28 (D)(1) based on the
				equivalent size of the largest supply conductor determined by the largest sum
				of the areas of the corresponding conductors of each set.
052 Grounding electrodes.
(2) Except for mobile/manufactured homes, a
				concrete encased grounding electrode must be installed and used at each new
				building or structure that is built upon a permanent concrete foundation. The
				electrode must comply, with NEC 250.52 (A)(3). Inspection of the electrode may
				be accomplished by the following methods:
(a)
				At the time of inspection of other work on the project, providing the concrete
				encased electrode is accessible for a visual inspection;
(b) At the time of the service inspection
				providing the installer has provided a method so the inspector can verify the
				continuity of the electrode conductor along its entire length, with a minimum
				20 foot linear span between testing points (e.g., attaching a length of copper
				wire to one end of the electrode that reaches the location of the grounding
				electrode conductor that will enable the inspector to measure the resistance
				with a standard resistance tester). The concrete encased electrode does not
				have to be accessible for a visual inspection; or
(c) Other method when prior approval, on a
				job site basis, is given by the inspector.
If a special inspection trip is required to inspect a
				  grounding electrode conductor, a trip fee will be charged for that inspection
				  in addition to the normal permit fee.
Exceptions:
(1) If the concrete encased grounding electrode is
							 not available for connection, a ground ring must be installed per NEC 250 or
							 otherounding electrode installed per NEC 250 verified to measure 25 ohms or
							 less to ground. Resistance verification testing must be performed by an
							 independent firm having qualified personnel and proper equipment. A copy of the
							 testing procedures used and a written resistance test record signed by the
							 person performing the test must be available at the time of inspection. The
							 resistance test record must include test details including, but not limited to,
							 the type of test equipment used, the last calibration date of the test
							 equipment, and all measurements taken during the test.
(2) Where a concrete encased electrode is not part of
							 the grounding electrode system of an existing building or structure, a concrete
							 encased electrode that may be available as a result of a new addition to the
							 foundation is not required to be connected to service equipment that existed
							 before the addition.