In the NEC^®, there are only a handful of places where selective coordination is required.

Two overcurrent devices are selectively coordinated when the downstream overcurrent device closest to the fault opens before the upstream overcurrent device can.

A faulty emergency light in one room of a building should only trip the 20-amp branch circuit breaker directly ahead of it in the electric panel rather than causing the main 200-amp breaker protecting the entire panelboard to trip. Poor coordination could potentially and unnecessarily shut down all loads supplied from the panel.

Often, no one knows whose job it is to ensure that selective coordination has been achieved on a new project. Its one thing to follow the plans and install the circuit breaker types shown on the plans, it’s another thing altogether to adjust the trip settings to ensure that the required selective coordination has been achieved. Many adjustable trip circuit breakers come from the factory with the dials adjusted to trip at the fastest setting.

In Oregon, the amendment to this section makes it clear in the following code language:

OESC 700 Emergency Systems.

Building officials and inspectors administering and enforcing the state building code under ORS 455.148 and 455.150, shall ensure compliance with Sections 700.32, 701.27, or 708.54 by verifying receipt of a certificate signed by the Engineer of Record or the Signing Supervisor stating that the proposed installation complies with the selective coordination requirements of this code.

Oregon amendments to the 2023 NEC^® are located in “Table 1-E” of the Oregon Electrical Specialty Code (OESC) which can be seen using the following link or the OESC PDF file located near the bottom of the screen: 2023 OESC