I conduct a number of National Electrical Code (NEC)-related seminars each month. Lately, people have been asking about the requirements for grounding and bonding systems together to provide an equipotential plane.
Communications systems and circuits in buildings must comply with the applicable rules in National Electrical Code (NEC) 2008 Article 800. Even though these systems operate at lower energy levels, improper grounding and bonding can result in severe consequences for equipment, property and people.
While preparing a presentation, I noticed a photo taken at a facility where temporary power was needed periodically. The facility rented a generator when necessary. It showed a disconnecting means with four individual conductors stubbed out of the bottom of the enclosure.
A veteren electrician asked what the National Electrical Code (NEC) requirements are for installing cord-and-plug-connected room air conditioners. I thought the answer might be interesting to others.
Determining ampacity and rating
Low voltage systems are often ungrounded, which is normal, but non-current-carrying metal parts of equipment associated with low voltage systems are generally required to be grounded if the supply system is grounded. This article reviews NEC requirements for grounding low voltage systems.
When installing recessed fixtures, carefully consider the location of the units. The presence of combustible materials surrounding the luminaire is very important, and recessed lights can act as chimneys for heat loss and moisture transfer into attic spaces.
A faithful reader of ELECTRICAL CONTRACTOR asked how to design and install high-voltage feeders according to the 2008 National Electrical Code (NEC). He requested that I write an article pertaining to such an installation.
The 2008 National Electrical Code (NEC) includes a new definition covering “Intersystem Bonding Termination” and a total rewrite of Section 250.94 covering the requirements for installing a bonding connection point for communications systems.
A contracting firm I work for is bent out of shape over the new revised Section 210.4(B) and (D) in the National Electrical Code (NEC). The firm, plainly speaking, said this was going to require time to police the trimming out of a panelboard.
Article 220 Branch Circuit, Feeder, and Service Calculations; Article 240 Overcurrent Protection; Article 250 Grounding and Bonding; Article 404 Switches; Article 700 Emergency Systems; Guide Information for Electrical Equipment Directory (White Book) published by Underwriters Laboratories Inc.
I recently did a workshop for a major city experiencing problems with inspections on photovoltaic (PV) systems during and after installation. The problem was between the inspection and fire department.
Selecting the correct size conductor involves referencing more than one section and more than one chapter in the National Electrical Code (NEC). The following questions must be answered before selecting conductors.