No, it is not acceptable to have NM cables in direct contact with heat ducts.Hazards



Overheating and Insulation Damage

The heat from the duct can damage the insulation of NM cables, increasing the risk of electrical shorts and fires.

Increased Temperature Ratings

NM cables are typically rated for a maximum temperature of 90°C (194°F). Heat ducts can exceed this temperature, further degrading the cable insulation.

Clearance and Insulation Requirements



Clearance from Ducts

NM cables must be kept at least

12 inches away from heat ducts. Insulation

If the clearance cannot be maintained, a minimum of

1 inch of thermal insulation must be placed between the cable and the duct. The insulation must be rated for a temperature of at least 150°C (302°F).

Alternative Solutions



Use Metallic Conduit

Install NM cables within metallic conduit to provide protection from heat and other hazards.

Relocate Cables

If possible, relocate the NM cables to an area where they will not be in contact with heat ducts.

Use High-Temperature Cable

Consider using cables specifically designed for high-temperature applications, such as THHN or XHHW wires.

Code Requirements



National Electrical Code (NEC) Article 334.80(B) requires a minimum of 12 inches of clearance between NM cables and heat ducts. International Building Code (IBC) Section 1104.1.1(3) enforces the NEC requirements.

Additional Considerations: Inspect the NM cables regularly for any signs of damage or overheating. If heat ducts are added or modified, ensure that they do not create a hazard for existing NM cables. always consult an electrician for professional advice and installation. Flag for review