What are overcurrent protection devices?

Overcurrent protection devices include circuit breakers and fuses. Overcurrent protection devices are meant to protect against the potentially dangerous effects of overcurrents, such as an overload current or a short-circuit current, which creates a fault current.

Where should an overcurrent protective device be located?

Overcurrent protection devices located next to equipment can be mounted above 6 feet 7 inches, if accessible by portable means. OCPDs must not be exposed to physical damage. Electrical equipment must be suitable for the environment.

Where must an overcurrent device be located in a circuit?

A – An overcurrent device shall be connected at the point where the conductor to be protected receives its supply. NEC Section 240.21.

How can we prevent overcurrent situations?

The most common of these protection devices are fuses, circuit breakers, and overcurrent relays. In cases where an overcurrent occurs, these devices will break the circuit through which the current is flowing, eliminating or re-routing the current flow.

When do you need an overcurrent protection device?

Article 240 provides the requirements for selecting and installing overcurrent protection devices (OCPDs). Depending on your application, other Articles may apply (see Other Articles below). An overcurrent exists when current exceeds the rating of conductors or equipment. It can result from overload, short circuit, or ground fault.

Can a thermal relay be used for overcurrent protection?

Thermal Devices. Thermal cutouts, thermal relays and other devices not designed to open short-circuits, shall not be used for protection of conductors against overcurrent due to short-circuits or grounds but may be used to protect motor branch circuit conductors from overload if protected in accordance with Section 430-40. 240-9.

What is the maximum overcurrent protection for copper?

Unless specifically permitted in 240.4 (E) or (G), overcurrent protection must not exceed (after ampacity adjustment and/or correction): 15A for 14 AWG copper. 15A for 12 AWG aluminum. 20A for 12 AWG copper.

When do you need to mark the available fault current?

The 2020 NEC added a new requirement in Section 408.6 for panelboards, switchboards, and switchgear that requires field marking of the available fault current in other than one- and two-family dwelling units. This is a significant change requiring nearly all electrical power distribution equipment to be marked with the available fault current.