The purpose of ground-fault protection on temporary wiring installations during construction, remodeling, maintenance, repair or demolition of buildings, structures or equipment is to ensure personnel protection.
In section 250.52(A)(2) of the 2005 and the 2008 editions of the National Electrical Code (NEC), the metal frame of a building or structure is considered to be a grounding electrode if the metal frame is connected to earth by one of four different methods.
A group of apprentices asked if there is an easy way to locate equipment and wiring method requirements in the Na-tional Electrical Code (NEC). If indeed there is a procedure, they wanted me to demonstrate such by designing and installing a motor system with examples.
Contractors often field calls from prospective customers regarding the installation of a fire alarm system. The customer has made the decision to protect his building and wants advice on how best to accomplish this goal.
Recently, I fielded a question about the basic statement in Section 695.3 of the 2008 National Electrical Code (NEC) that “electric motor-driven fire pumps shall have a reliable source of power.” The question involved the reliability of the power source for one of the most important electrical motor
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.
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
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.
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.