Code Change Summary: A new code section requires separation when equipment operating at 1000 volts or less is located in the same vault, room or enclosure as equipment operating over 1000 volts.

Read carefully, this can be a big change, depending on how it is interpreted.

“Where switches, cutouts, or other equipment operating at 1000 volts, nominal, or less are installed in a vault, room, or enclosure where there are exposed live parts or exposed wiring operating over 1000 volts, nominal, the high-voltage equipment shall be effectively separated from the space occupied by the low voltage equipment by a suitable partition, fence, or screen”.

This code change is likely to see additional changes in 2020 because of the subjective terminology (in bold) that leaves much open for interpretation. Below is a breakdown of the loose code language that can create issues when applying this code change:

• The term “equipment” can mean just about anything. Article 100 defines “equipment” as A general term, including fittings, devices, appliances, luminaires, apparatus, machinery, and the like used as a part of, or in connection with, an electrical installation.
• “Effectively” is vague. What one considers to be effective, others may not.
• A “suitable” partition, fence or screen does not provide clear direction for the code reader.

This code change, when applied as intended, can create a safer work situation. The code change will most likely affect indoor electrical rooms at large facilities where switchgear often operates at 12,470 volts or more.

Below is a preview of Article 110. See the actual NEC^® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2017 NEC^® edition of NFPA 70.