Fire Alarm Systems, based on the 2017 NEC - Mike Holt
Cable used in a wet location must be listed for use in wet locations or have a moisture-impervious metal sheath. Fire alarm cable must have a voltage rating of at least 300V and (new with the 2017 NEC) a temperature rating of at least 60 DegrC [760.179(C)].
Article 555 - Marinas, Boatyards, and Docking Facilities, based on …
An individual branch circuit of the voltage class and rating corresponding to the rating of the receptacle must supply each receptacle that supplies shore power to boats. Informational Note: Supplying 120/240V, 3-wire receptacles from a 120/208V, 3-wire supply may cause overheating or malfunctioning of connected equipment.
Code Forum Recap - 2018 - Mike Holt
Do you have any information regarding the re-use of wire nuts? Some claim that we should discourage re-use despite common practice. Gary January 9 2019, 1:10 pm EST
Flexible Cords and Fixture Wires, based on the 2023 NEC
Flexible cords Article 400 covers the general requirements and applications for flexible cords as contained in Table 400.4. The NEC does not consider flexible cords to be a wiring method like those addressed in Chapter 3 because they are not used as part of the wiring in the construction of a building. Flexible cords (and their fittings) must be suitable for the use and location …
Safety - Electrical Outlet Covers - Mike Holt
Safety – Electrical Outlet Covers “Hi Mike, I'm not an electrician nor studying to be one, but I've been educating myself on some basics just to be able to correct some problems with switches and receptacles around our house such as exposed switches with no covers because somebody put paneling on the walls and did not correct recessed boxes so covers could be put on, …
Switchboards and Panelboards, based on the 2023 NEC
Article 408 covers the requirements for switchboards and panelboards that control power and lighting circuits. Bus arrangement Panelboards supplied by a 4-wire, delta-connected, three-phase (high-leg) system must have the high-leg conductor (which operates at 208V to ground) terminate to the “B” phase of the panelboard [408.3(E)(1)]. Such a panel or switchboard must have a …
Code Forum Recap - October 2022 - Mike Holt
18: Melting wire nuts with 28 replies in the General Electrical Forum 19: EV charging with 28 replies in the General Electrical Forum 20: 14/2 and 18/2 with 28 replies in the General Electrical Forum
Article 310 - Conductors for General Wiring, based on the 2017 NEC
The neutral conductor of a 4-wire, three-phase, 120/208V or 277/480V wye-connected system is considered a current-carrying conductor for conductor ampacity adjustment of 310.15(B)(3)(a), but only if more than 50 percent of the load is nonlinear [310.15(A)(5)(c)].
Services, based on the 2023 NEC - Part 1 - Mike Holt
You can't use trees or other vegetation to support overhead service conductor spans or service disconnects [230.10] Conductor spans above roofs must maintain a vertical clearance at least 8 ft 6 in. above the surface of a roof for a minimum distance of 3 ft in all directions from the roof edge [230.24(A)]. Five exceptions exist. For example:
Free Videos - Mike Holt
How to use the National Electrical Code (29min:14sec) 2020 Aluminum Conductor Termination Methods (3min:29sec) 2022 Air-Conditioning, Circuit Sizing (8min:53sec) 2022 Ampacity Table [310.15] (13min:25sec) 2020 Adjustable-Speed Drives [430 Part X] (15min:31sec) 2020 Arc-Flash Hazard Warning 110.16 (23min:50sec) 2020