Code Change Summary: New subsection about field-applied hazard markings.

Many places in the NEC^® require “WARNING”, “CAUTION”, or “DANGER” signs. Until now, there has been no clear direction given on what is considered a proper label that adequately warns of the potential hazard.

Now, any time the NEC^® requires a hazard marking, and section 110.21(B) is mentioned, the labels must adequately warn of the hazard with effective words, colors or symbols. These labels cannot be handwritten (other than portions of the label that may have variable values or information that is subject to change).

The new code language also includes an informational note referencing ANSI Z535.4-2011, Product Safety Signs and Labels which provides guidelines on how to make proper hazard signs and labels.

Some NEC^® examples where specific hazard markings are required:

110.16 requires a WARNING label to warn the qualified electrician that an arc-flash hazard exists at switchboards, switchgear, panelboards, industrial control panels, meter socket enclosures, and motor control centers, that are in other than dwelling units, and are likely to require examination, adjustment, servicing, or maintenance while energized.

110.22(B) requires a CAUTION marking for series rated systems where two overcurrent devices are working together to eliminate a fault condition that exceeds the AIC rating of the lowest rated circuit breaker.

110.34(C) requires a DANGER sign at the entrance to all buildings, vaults, rooms, or enclosures containing exposed live parts or exposed conductors operating at over 600 volts.

Below is a preview of the NEC^®.  See the actual NEC^® text at NFPA.ORG for the complete code section. Once there, click on the “free access” tab and select the applicable year of NFPA 70 (National Electrical code).