One embodiment of the present invention provides a circuit which blocks a keeper from interfering with a dynamic node during an evaluation phase for a dynamic wide-NOR structure. The electrical junction box has a casing assembly including an upper casing and a lower casing. The ESD potential between the electrodes andor the wheels may be measured in several selected modes for point to point, point to ground and point to bench top measurements. A method to assemble a portable tack rack from a plurality of rigid members and, optionally, one or more flexible mesh structures is disclosed.