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Code Change Summary: New requirement added to existing text. For other than one- or two-family dwellings, the 2020 NEC ® will require additional marking to identify where a disconnecting means is fed from.
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. The purpose of a disconnecting means located remotely from the equipment it serves may not be clear and would require field identification to identify what it supplies. Then again, the purpose of a disconnecting means directly adjacent and connected to an air conditioner it serves is evident and further identification would not be required, that is, until the 2020 NEC ® is adopted.
In the 2020 NEC ® , new code language will require any disconnecting means, in other than one- or two-family dwellings, to be field marked to identify the circuit source that supplies it. This code change is a move to promote safety by ensuring that a service electrician or building owner can easily shut off the 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 2020 NEC ® edition of NFPA 70.
2017 Code Language:
110.22(A) General. Each disconnecting means shall be legibly marked to indicate its purpose unless located and arranged so the purpose is evident. The marking shall be of sufficient durability to withstand the environment involved.
2020 Code Language:
110.22(A) General. Each disconnecting means shall be legibly marked to indicate its purpose unless located and arranged so the purpose is evident. In other than one- or two-family dwellings, the marking shall include the identification of the circuit source that supplies the disconnecting means. The marking shall be of sufficient durability to withstand the environment involved.
Below is a Real Question from our Electrical Continuing Education Courses for Electrical License Renewal:
Refer to the image of a group of stainless steel disconnect switches at a wastewater treatment facility:
Based on the 2020 NEC, which of the following is true?
