National Electrical Code
Derating Current-Carrying Conductors for Conditions of Use
If you ask a seasoned electrician how many No. 12 AWG conductors will fit into a 3/4″ EMT conduit system, you may get a response such as “one more!” While this is amusing (and typically true), there are precautions that must be taken according to the NEC whenever conductors are bundled together in a raceway, cable, or even in a ditch in the earth.
New Articles in the 2020 NEC
There will be four new article additions to the 2020 NEC:
1. Article 242 Overvoltage Protection
2. Article 311 Medium Voltage Conductors and Cable
3. Article 337 Type P Cable
4. Article 800 General Requirements for Communications Systems
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.
330.15 New Standards for Installing MC Cable
New for the 2017 NEC 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.