The Mike Holt Podcast

210.8 GFCI Protection - https://www. Mikeholt.com/code. There’s no doubt that ground-fault circuit-interrupters have protected many people from electrical hazards. This Code cycle there is an increased emphasis on GFCI protection and many new locations that require GFCI protection have been added. The 2020 changes and revisions to this section are numerous and include clarifications, expansions to...

300.21 Fire-Rated Walls, Ceilings, and Floors – https://www. MikeHolt.com/code. Wherever there’s airflow, the potential for a fire to spread exists. The requirements in section 300.21 of the NEC are designed to prevent, as much as possible, increasing the spread of fire where electrical installations may decrease fire-resistive ratings of walls, ceilings, and floors. In this podcast, you’ll learn...

A fire pump wouldn’t be of much use during a fire if the circuit conductors that supply it failed. Sizing these conductors isn’t the same as sizing other motor conductors. Listen to this podcast to ensure that you’re sizing fire pump circuit conductors correctly.

Service conductors supplying the entire load associated with a dwelling unit can be sized in accordance with Table 310.12 but are there any rules or considerations before using this table? What about if it’s a feeder instead? The answers to these and many other questions can be found by listening to this podcast on sizing these service/feeder conductors.

250.122 Equipment Grounding Conductor, Sizing – https://www. MikeHolt.com/bonding . The equipment grounding conductor sizes for 15A -30A circuits are easy to remember since they are required to be full sized and are part of cable assemblies. Larger circuits, however, typically require the use of Table 250.122 and that can be a little confusing. Listen to this podcast to better understand how these...

250.119 Equipment Grounding Conductor Types – https://www. MikeHolt.com/bonding . Equipment grounding conductors can be identified in several ways. In this video clip, we discuss how the NEC requires these conductors to be identified.

There is now so much sustainable electrical energy being produced that we need to find ways to store it! An Energy Storage System (ESS) consists of one or more components capable of storing electrical energy for future use. Article 706 in the NEC covers the requirements for ESS and it’s important to understand what Article 706 does and does not apply to. Find out why in this podcast on the Scope o...

For most of us, a loss of utility or normal electrical power is an inconvenience and is usually restored as soon as humanly possible. But where electrical power is essential for maintaining safety to human life, an emergency electrical system is required. Do you know what types of occupancies might require this consideration and who classifies these systems as emergency? To answer these questions...

For years, a common practice for one and two-family dwellings has been to install a meter enclosure outside and main breaker panel suitable for use as a service disconnect inside. As electrical professionals, many of us had that hunch to ask ourselves, "what about first responders." A recently added Code rule now requires an emergency disconnect for ALL one and two-family dwellings regardless of t...

Electric vehicles have been around for a long time. With bi-directional transfer of electrical power from your electric vehicle to your home becoming commonplace, the industry has had to adapt and the scope of Article 625 has changed again. Listen to this podcast to learn the scope of what’s covered in this article and what has changed since the last cycle.

250.122(F) EGC for Parallel Conductors, Sizing – https://www. MikeHolt.com/bonding. One of the costliest mistakes made in electrical installations is a failure to read and fully understand the Code rules for sizing and installing the EGC when paralleling conductors. Read your Code book while listening to this podcast and you could wind up saving yourself a huge amount of aggravation and money!

When three conductors are pulled into a raceway, they may flatten out creating a condition where the conductors could jam. In this podcast we’ll explain how to avoid this condition.

Factors that impact conductor sizing include not only conductor ampacity and equipment terminal temperature rating, but also the conductor insulation temperature rating. In this podcast we discuss Table 310.4(A) which provides information on conductor insulation properties such as letter type, maximum operating temperature, application, insulation, and outer cover properties.

To understand when to apply the requirements of Article 725 for remote-control and signaling circuits, you need to understand the Scope of this article. Listen to this podcast and discover what distinguishes “Class 1” from “Class 2” and “Class 3” circuits and what this article applies to.

210.4 Branch Circuit, Multiwire – https://www. MikeHolt.com/code . Multiwire branch circuits are an efficient and cost-effective approach to installing electrical circuits, but there are inherent hazards when this wiring method is used. In this podcast, we discuss how important it is for these circuits to be installed and serviced properly, and the consequences for failing to do so!

810.21 Bonding, Radio Antenna Grounding – https://www. MikeHolt.com/bonding . You may be surprised at the number of CB and HAM radio operators there are around the country. These radio frequencies require line-of-sight antenna which requires a substantial height (some are hundreds of feet tall) to maintain that line-of-sight. You can probably already figure out that these heights make them a prime...

250.96 Bonding, Other Enclosures – https://www. MikeHolt.com/bonding . If you remember that the whole purpose of bonding is to establish an “effective ground-fault current path” in order to clear a fault, then you can better understand why proper bonding of enclosures and raceways is crucial in maintaining a safe electrical installation.

250.97 Bonding, Metal Raceways – https://www. MikeHolt.com/bonding . If you remember that the whole purpose of bonding is to establish an “effective ground-fault current path” in order to clear a fault, then you can better understand why proper bonding of raceways is crucial in maintaining a safe electrical installation.

250.94 Bonding, Communications Equipment – https://www. MikeHolt.com/bonding . Many believe that because of lower the operating voltages of communications systems, proper bonding of such systems is no big deal. That couldn’t be further from the truth! Find out why intersystem bonding and creating a “zero” potential is an important factor in a safe electrical system.

250.102 Bonding Jumper, Supply Side – https://www. MikeHolt.com/bonding . There are basic rules for supply-side bonding jumpers, find out just what those rules are in this video clip.

Mike Holt discusses Overvoltage Protectors with John Cavaroc, Ph. D., P.E. from Safe Laboratories and Engineering Corp.

110.16 Arc-Flash Hazard Warning Label – https://www. MikeHolt.com/code . What’s an arc-flash warning label? Where do these warnings need to appear? Who’s responsible for posting these warnings? The answers to these questions (and more) are discussed in this podcast on section 110.16 of the NEC.

The number of conductors in the same raceway that are carrying current can affect conductor ampacity, as can the ambient or surrounding temperature. In this video we’ll explain how to evaluate these factors to make the proper choice when sizing electrical conductors.

440.4(B) Air-Conditioning, Circuit Sizing – https://www. MikeHolt.com/code . The first time you’re called upon to size a conductor and overcurrent device for central air-conditioning and you look at the nameplate requirements that clearly state that a 10 AWG copper conductor and a 50A OCPD are required, it may contradict everything you’ve learned about small conductors. In fact, you may adamantly...

Adjustable-speed drives can be variable-frequency speed drives(VFDs)—which refer to alternating-current drives only, or variable-speed drives (VSDs) which can be alternating-current or direct-current drives. Either of these can vary the speed of a motor, one by altering frequency and the other by adjusting voltage. But how does this affect the conductor sizing for the motor branch circuit? Does it...