Search

With the advent of systems at frequencies above 60 Hz, we've seen increased interest in the rating of cables in these applications. Mainframe computer systems, running at 400 Hz, certainly [...]

All questions and answers are based on the 2008 NEC. Q. When a single generator is used to provide standby power for emergency and nonemergency loads, can one transfer switch [...]

Separately derived systems (SDSs) include most transformers as well as any generator or UPS supplying a transfer switch that opens the neutral conductor. What makes a system 'separately derived?' It's [...]

As usual, never consider the following commentary associated with these photos as a formal interpretation of the National Electrical Code (NEC). Without criticizing anyone or any product, the following scenarios [...]

All questions and answers are based on the 2005 NEC. Q. Can I pass conductors from one panel through another panel? If so, what are the restrictions? A. Yes, cabinets, [...]

All questions and answers are based on the 2005 NEC. Q. Since the neutral is bonded to the case at the meter enclosure, do I still need to bond the [...]

Article 210 contains the requirements for conductor sizing, conductor identification, overcurrent protection, and GFCI and AFCI protection of branch circuits. It also contains requirements for receptacle outlets and lighting outlets. [...]

Have you done any service work lately, and noticed a spark as you connect or reconnect the grounding electrode conductor to the ground rod of what appeared to be a [...]

Do you know the special grounding requirements involved in bonding to steel? When you think of grounding, you may visuatize ground grid conductors, electrodes, interconnections-all buried in the soil. But, [...]

How to use the grounded neutral conductor as an equipment-grounding conductor. The NEC says you can use the grounded neutral conductor to ground the noncurrent-carrying metal parts of frames and [...]

When and how to install grounding electrode conductors from separately derived systems on the upper floors of a building can be a challenge. WE HAVE received a number of questions [...]