240.6(D) Remotely Accessible Adjustable-Trip Circuit Breakers.

Section 240.6(D) was added to address some of the newer circuit breakers available that have adjustable settings which can be accessed remotely by a computer, smartphone, or tablet.
Click to Enlarge
Section 240.6(D) was added to address some of the newer circuit breakers available that have adjustable settings which can be accessed remotely by a computer, smartphone, or tablet.

Code Change Summary: New code section on remotely accessible adjustable-trip circuit breakers.

Many circuit breakers have adjustable trip settings to alter the circuit breaker trip curves to selectively coordinate with other devices. These settings should not be modified other than by qualified persons who are familiar with the system design.

In Section 240.6(C), prior to the 2020 NEC®, adjustable circuit breaker settings required restricted access by measures such as removable and sealable covers over the adjusting means, or bolted equipment enclosure doors, or installation behind locked doors accessible only to qualified personnel.

In the 2020 NEC®, Section 240.6(C) saw a new line item 4 which included password protection as a method to provide the required “restricted access”. Circuit breakers with newer electronic trip units provide the ability to require a password to keep unauthorized users from changing the settings.

In the 2023 NEC®, new Section 240.6(D) was added to address some of the newer circuit breakers available that have adjustable settings which can be accessed remotely by a computer, smartphone, or tablet.

Newer technologies such as remotely accessible adjustable circuit breakers have many benefits but can also bring vulnerabilities since these devices have provisions to be accessed, monitored, and adjusted from a computer.

Cyberattacks are now a threat to network connected building life-safety equipment and other critical systems which can negatively affect their ability to operate in their essential roles.

The new 2023 NEC® language in Section 240.6(D) permits circuit breakers that can be adjusted remotely to have an ampere rating equal to the adjusted current setting (long-time pickup setting) if one of the following methods is utilized to ensure restricted access is maintained:

(1) The remote access is connected directly through a local non-networked interface.

(2) The remote access is connected through a networked interface complying with either of the following methods:

a. The circuit breaker and associated software for making remote adjustments are identified as being evaluated for cybersecurity.

b. A cybersecurity assessment of the network has been completed. Documentation of the assessment and certification must be made available to those authorized to inspect, operate, and maintain the system.

Section 240.6(D) Informational notes 1, 2, and 3 provide references to cybersecurity standards, examples of commissioning certification, and remind the code user that cybersecurity is a specialized field which requires constant monitoring of security vulnerabilities that could arise from defective software, system changes, or user interactions.

When considering accepting an installation that is vulnerable to cyberattacks, inspectors and plans examiners will likely begin to ask for assurance that the electrical equipment has some sort of framework to mitigate current and future cybersecurity vulnerabilities and address the integrity of the software that will be used for the installation.

Below is a preview of the NEC®. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2023 NEC® edition of NFPA 70.

2020 Code Language:

This code section did not exist.

2023 Code Language:

N 240.6(D) Remotely Accessible Adjustable-Trip Circuit Breakers. A circuit breaker(s) that can be adjusted remotely to modify the adjusting means shall be permitted to have an ampere rating(s) that is equal to the adjusted current setting (long-time pickup setting). Remote access shall be achieved by one of the following methods:

(1) Connected directly through a local nonnetworked interface.

(2) Connected through a networked interface complying with one of the following methods:

a. The circuit breaker and associated software for adjusting the settings are identified as being evaluated for cybersecurity.

b. A cybersecurity assessment of the network is completed. Documentation of the assessment and certification shall be made available to those authorized to inspect, operate, and maintain the system.

Did You Like This? Let Us Know With A Like! Thanks!

240.6(D) Remotely Accessible Adjustable-Trip Circuit Breakers.

Below is a Real Question from our Electrical Continuing Education Courses for Electrical License Renewal:

Based on the 2023 NEC, which of the following is an acceptable method to ensure restricted access to remotely adjustable overcurrent devices?

A: The remote access is connected directly to the Homeland Security Office.
B: The remote access is connected directly to the FBI.
C: The remote access is connected directly through a local nonnetworked interface.
D: The remote access is connected directly to the police department.
Please register or sign in for electrical continuing education courses.

If you were already signed in, your session probably expired, please sign back in.