2017 National Electrical Code

Conductor Derating on a Rooftop Made Easy

Derating conductors for the environment where they are installed is an important consideration for selecting the type and size of conductor for a particular installation. When installing a system on a rooftop, special consideration must be given to the ambient temperature inside the wire way or conduit that contain the conductors to prevent heating beyond the rating of the insulation of the conductors.

Conductors installed in raceways on rooftops can be subject to higher temperatures than they would be just from the heating effect of solar energy absorbed by the wall of the raceway. This effect becomes more evident when the proximity is very close to the roof or the raceway is in contact with the roof surface.

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Conductor Derating on a Rooftop Made Easy

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Stepping Up and Stepping Down: Using Transformers to Change Voltages to Desired Levels

Transformers are used when power voltages need to be changed, or transformed, to other levels. Sometimes voltages need to be increased when sending power long distances. Other times, voltages need to be decreased for equipment that uses the power. Regardless of whether the voltages are being stepped up or stepped down, the same process of changing windings is used to transform voltages to different levels.

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JADE Learning Offers Updated Electrical Exam Prep and CE for the California Building Standards Commission’s 2017 NEC Adoption

The California Building Standards Commission voted to adopt the 2017 National Electrical Code (NEC). The adopted codes were published on July 1, 2019, and became effective on January 1, 2020. With the adoption of the new code, there are now new requirements for the California Electrical Certification Continuing Education and California Electrical Certification Exam.

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Understanding Box Fill Calculations: Must-Have Knowledge for Installers and Inspectors – NEC 2017, Article 314.16

Can you do a box fill calculation at the jobsite? This is an important skill for installers and inspectors alike, since a box that is overfilled can cause a fault, arcing, or even a fire. But how do we determine if a box is overfilled in a real-world situation?

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How to Pass 99% of Your Electrical Inspections

Recently while working as an electrical foreman I was able to pass fifty – yes, fifty!- electrical inspections in a row. I was a rock star to my crew, the GC and my employer. The crew respected me. I was keeping the project schedule on track. I was saving the company money in permitting fees and labor. I didn’t have to work an enormous amount of overtime, and I didn’t have to bring in bags of unmarked bills on inspection day. What I did is simply follow this basic procedure.

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Grounding Electrodes – to be or not to be? 2017 NEC 250.52(B)(3)

Prior to 2017, only two items were prohibited for use as grounding electrodes, underground gas piping and aluminum. For 2017, another item has been added to the list of prohibited items. For the 2017 NEC Code cycle, the structures as well as steel reinforcement materials that pertain to swimming pools have been added to the list found in 250.52(B)(3) of components that are prohibited from being used as grounding electrodes for an electrical system.

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Conduit and Cables Exposed to Sunlight on Rooftops

Anyone who has been on top of a roof on a hot summer day knows what it’s like to stand in the middle of an oven. Extreme temperatures from the sun can bake everything in sight, from shingles to appliances, and even electrical conductors and conduit.
Conductor insulation is meant to provide long lasting protection from expected heat due to the flow of electricity and normal environmental factors. However, excessive heat from solar radiation can damage conductors and cause premature failures.

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Field Labeled & Field Evaluation Body (FEB)

Two new terms found in Article 100, and a clarified evaluation-practice established for the 2017 NEC code-cycle
Electrical equipment is generally approved by a testing laboratory before being shipped by a manufacturer. However, sometimes electricians may need to install spe-cialized gear that has not yet been formally certified. When field certification is neces-sary due to a lack of a UL (or other approved laboratory) Listing, electricians are then required to contact a Field Evaluation Body (FEB) to receive an approval label. Fortunately, updates and new terms in the 2017 NFPA 70 National Electrical Code (NEC) help clarify what should be done when items need to be field labeled by a Field Evaluation Body (FEB).

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NEC 210.52(C)(3) New Peninsular Receptacle Requirements for the 2017 NEC

The method for measuring the countertop space for peninsulas has been changed for 2017. We know that NEC Section 210.52 requires that at least one receptacle be provided for each island or peninsula countertop that fits the dimensional requirements. The intent of the Code here is to discourage the use of extension cords. For example, countertop outlets must be spaced so that the typical two-foot extension cord can reach an outlet from any part of the countertop. Previously, the minimum distance triggering the outlet requirement was measured from the junction where the peninsula abutted the front edge of the perpendicular countertop, thus usually requiring an outlet mounted in the peninsular base cabinet. The new method of measurement begins at the wall behind the countertop.

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How To Apply Ohm’s Law

Electricity operates within predictable boundaries. We have come to identify these boundaries as Ohm’s Law. Ohm’s Law was developed as a means of explaining how electricity operates within a closed circuit. The Ohm’s Law formula helps to communicate the relationship between different properties within an electrical circuit. We can use Ohm’s Law to explain what has occurred, as well as what will occur, when certain conditions are imposed upon an electrical circuit.

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