Code Change Summary: Deleted text changes the rules on overcurrent device enclosure orientation.

In the 2020 NEC^®, a longstanding issue with overcurrent device orientation has been cleared up by deleting the words “unless that is shown to be impracticable” from the 2017 NEC^® Code Language below.

Previously, a fused disconnect switch or panelboard cabinet was required to be installed vertically unless it was “shown to be impracticable”. This language commonly led to fused disconnect switches above a suspended ceiling installed face down (see image) or panelboard cabinets installed face up in commercial laundromats behind the washers and dryers in a laundry bulkhead.

Mounting an overcurrent device enclosure horizontally or face up increases the likelihood that contaminants can accumulate on the circuit breakers or busbars. In addition, providing the required working space can prove to be almost impossible.

The only conflict left is the second sentence that states “circuit breaker enclosures shall be permitted to be installed horizontally where the circuit breaker is installed in accordance with 240.81”. If understood correctly, and read along with the requirements in 240.81, technically, as long as the circuit breakers are marked with an “on” and “off” position (like most are), then the enclosure can still be mounted horizontally.

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.