Code Change Summary: New language was added that requires marking the location of the circuit source.

Since 1965, the NEC^® has required each disconnecting means to be legibly marked to indicate its purpose unless located and arranged so the purpose is evident.

If the purpose of a disconnecting means located remotely from the equipment it serves is not clear it requires field identification to identify what it supplies. On the other hand, the purpose of a disconnecting means located directly adjacent and connected to an air conditioner it serves is evident and further identification is not required.

In the 2020 NEC^®, the existing language was expanded with another provision, specific to other than one- or two-family dwellings, requiring a disconnecting means to be field marked to identify the circuit source that supplies it.

In the 2023 NEC^®, this concept was taken a step further. Now, if the purpose of a disconnecting means in other than one- or two-family dwellings is not evident, not only is the circuit source required to be marked, but the “location” of the circuit source as well.

It’s not enough to know that a circuit from panelboard H-1 supplies a remote disconnect if nobody knows where to find panel H-1.

This code change is a move to promote safety by ensuring that a service electrician or building owner can easily shut off the circuit supplying a disconnecting means in the event of a problem.

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.