Article 250 is arguably the most important article in NEC 70, and much of its content is devoted to the proper sizing and installation of equipment grounding conductors. First, let us consider the purpose of an equipment grounding conductor (EGC). We know that EGC’s provide a low impedance path from the equipment to the overcurrent protective device (or ground detector for high-impedance grounded systems) so that a fault condition can be quickly cleared. Hence, EGC’s are a critically important safeguard to persons and equipment.
Metal-Clad (MC) Cable is used every day in the electrical industry. The true conduit benders hate it. The value engineering people love it. MC Cable is really a great product, has a wide variety of uses, and can be installed to look good. Let’s take a closer look at this industry workhorse: Metal-Clad Cable.
MC Cable Definition
MC Cable, by most common definition, is a factory assembly of one or more insulated circuit conductors enclosed in an armor of interlocking metal tape or a smooth or corrugated metal sheath. The smaller cables should be unsheathed by using an armored cutter like the famous “Roto-Split”. The fittings must be listed and identified for use. If the manufacturer provides anti-short bushings, they can be used. The bushings are not an NEC requirement since the listed MC connectors provide the conductor protection from sharp edges.
Have you ever compared your NFPA 70 book with a colleague and found that there were differences, though both books were the same edition of the NEC? We know that we receive a new edition of the NEC every three years, but how does the Code change between cycles?
NEC Section 230.71. Six Switches or Circuit Breakers in One Enclosure
Since the 1937 edition of the NEC, the service disconnecting means used to isolate a building’s premises wiring from the utility provider’s conductors has been allowed to consist of as few as one, but as many as six switches or sets of circuit breakers.
A veteran electrician would tell you that requirement (or permission, depending on your perspective) means six throws of the hand can be used to control all power on the property. Our veteran electrician is correct – if there is one electrical service on the property.
Under Floor Electric Cable and Cable Mat Systems are a great way to warm or even heat a space. These systems can be a supplemental or even a main source of heat in a variety of rooms. The systems can be installed under many types of floors such as tile, wood, concrete, vinyl, and even carpet. The manufacturers offer a variety or pre-engineered packaged units and even piece-by-piece options. The manufacturer’s step-by-step installation instructions must be used to install the heating cables, mats, spacers, thermostats, and other associated equipment. The instructions will also point us in the right direction as far as the branch circuit size but will most likely not give all of the needed information.
Bathroom branch circuit requirements have changed for the 2020 Code cycle. The one 20-amp branch circuit traditionally required by NEC Section 210.11(C)(3) to feed only receptacles in dwelling unit bathroom(s) is now restricted to feeding only countertop receptacles in those same bathroom(s).
The receptacles permitted on this newly defined branch circuit include any countertop receptacles required to be within 3 feet of the bathroom’s sink basin and any other receptacle(s) installed to serve countertops or similar work surfaces in these bathroom(s).
The need for a residential backup generator can vary in different areas of the country. The generator size and installation technique can also vary depending on your level of needed convenience and budget. Let’s take a look at a few different generator installation packages so you can decide what could be the best option for you and your family.
Chapter 7 of the 2020 National Electrical Code (NEC), also known as NFPA 70, covers special conditions and their specific requirements. These requirements modify the general requirements found in Chapters 1-4. Article 700 covers emergency systems, such as hospitals or similar settings where a power outage would put lives in jeopardy. Article 701 covers legally required standby systems and Article 702 covers optional standby systems.
The 2020 National Electrical Code (NEC) has ushered in a brand-new method for determining the number of receptacle outlets required to serve island countertops; peninsular countertops; and work surfaces located in kitchens, pantries, breakfast rooms, dining rooms, and similar areas of a dwelling unit.
The electrical service change is a very common electrical service job. Your standard residential service electrician could complete one on any given day, and it would be an easy task for him. For the rest of the electricians out there, a quick refresher may be needed before diving into an electrical service change. Let’s review some typical service change details and procedures using the 2017 National Electrical Code (NEC).
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