Code Change Summary: New code language was added in Part III of Article 230 to specify how far apart the hazard labels must be placed to identify cable trays containing service entrance conductors.

Service entrance conductors are required by 230.70(A)(1) to be disconnected at or nearest the point where the conductors enter a building. Because of this, it’s not very often that cable trays are used to support service entrance conductors. Most of the time, cable trays do not contain service entrance conductors because cable trays are generally installed downstream of the service disconnect.

If a cable tray is in fact used to support service entrance conductors, labels are required on the cable tray so that the servicing electrician is aware that unprotected, unfused service entrance conductors are located on the cable tray. It is important to know that shutting off the service disconnect will not de-energize all conductors in the cable tray.

The 2014 NEC^® requires the labels to be visible after installation and spaced no further than 10 ft. apart. The label ensures that the service entrance conductors can be traced throughout the cable tray.

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).