UL67 Section 5.4 Service Equipment
According to the Occupational Safety and Health Association there are more than 92 work-related deaths per week. A little over eight percent of those are caused by electrocution, most of which occur by inadvertent contact with energized objects.
The UL67 standard has been updated for the purpose of enhancing safety in electrical distribution panels. The revision, which takes effect January 1, 2017, requires panel manufacturers to provide protective devices that guard against inadvertent contact with exposed energized parts. All manufacturers must comply with the UL changes, but the methods they use will vary. The new requirement also appears in the 2017 National Electrical Code® (NEC), with timing subject to state-specific adoption.
The change applies any time a panel is being used as service entrance equipment, whether it’s a main breaker load center, panelboard, or combination service entrance device (CSED) application. Even with the barrier in place, the panel must still be de-energized before removing the deadfront, but the new requirement guards against inadvertent contact with any exposed line side parts that would still be energized unless the upstream meter is pulled.