Aug 29, 2019
Two new terms found in Article 100, and a clarified evaluation-practice established for the 2017 NEC 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).
Aug 29, 2019
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.
Aug 07, 2019
It’s mid-January and 15 degrees outside. A fresh snow has fallen and covered all the roads and yards in your neighborhood. Thanks to your natural gas furnace, your home is a toasty 70 degrees. This is because a properly installed gas furnace has a large temperature rise that heats your home quickly and works very well on high demand days. Could it be possible that a new gas furnace will be unavailable as a home heating appliance in the coming decades? Not only is it possible, it is probable.
Aug 07, 2019
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.
Aug 07, 2019
New for the 2017 code cycle is section 330.15, entitled “Metal-Clad Cable: Type MC Exposed Work.” This new Code section requires an exposed run of MC Cable to closely follow the surface to which it is mounted while enjoying a new permission that allows the MC cable to be installed on the underside of floor joists.
Jul 02, 2019
There is an old joke among HVAC contractors. When bidding on a replacement system for a customer, step back 100 feet from the house and hold up your hand. If three fingers will block the view of the house, install a three-ton unit. If it takes four fingers to block the view, then install a four-ton unit. That meager attempt at humor does highlight an issue that has been kicked around since the beginning of the industry. Are load calculations necessary? If so, how do you properly size a heating and air conditioning system for a house or commercial building?
Jul 02, 2019
Prior to the 2017 edition of the NEC, 120-volt receptacles equipped with USB charging outlets had not been addressed by the National Electrical Code. Universal Serial Bus (USB) connections have been around since the 1990s and are widely used to charge portable devices and computer peripherals, as well as transfer data.
Jul 02, 2019
It is no surprise that Ground Fault Circuit Interrupter protection has again been expanded in the 2017 edition of the National Electrical Code. Since its inception in the 1971 edition, GFCI coverage has been expanded and tweaked with just about every code change. In this edition, coverage has been increased in several significant ways, but an important clarification has also taken place. Specifically as regards protection for 15 and 20 amp outlets near sinks, the point at which the measurement is taken as well as the method to be used to measure the 6-foot distance has been clarified.
