In cable trays, which statement is true about communication cables?

In cable trays, which statement is true about communication cables?

• A. Only CMX cables may be used in cable trays.
• B. No communication cables may be used in cable trays.
• C. All communication cable types except CMX may be used in cable trays.
• D. Only fiber optic cables may be used in cable trays.

Answer: (C)

In cable trays, you can run most communication cables as long as the cable is listed for use in a tray. The key point is the listing and rating of the cable, not the general type. The only common exception is CMX, which is not permitted in cable trays; all other communication cable types (such as other CM variants) are allowed when they’re listed for tray installation. This reflects how the NEC treats tray installations: what matters is the cable’s listed use in that environment, including fire and heat considerations. Fiber optic cables are also allowed where the listing permits, but the important takeaway is that CMX is the one that’s excluded, while the others can be used in trays.

In cable trays, you can run most communication cables as long as the cable is listed for use in a tray. The key point is the listing and rating of the cable, not the general type. The only common exception is CMX, which is not permitted in cable trays; all other communication cable types (such as other CM variants) are allowed when they’re listed for tray installation. This reflects how the NEC treats tray installations: what matters is the cable’s listed use in that environment, including fire and heat considerations. Fiber optic cables are also allowed where the listing permits, but the important takeaway is that CMX is the one that’s excluded, while the others can be used in trays.