What should not be used to seal spare or unused raceways?

The choice of sealants not compatible with cable insulation as a means to seal spare or unused raceways is essential for ensuring safety and maintaining the integrity of the electrical system. The use of incompatible sealants can lead to deterioration of the cable insulation, possibly resulting in exposure of conductors to moisture and environmental contaminants. This can significantly increase the risk of electrical faults, shorts, or even fire hazards.

Proper sealing materials must be used to protect the raceways and their contents from moisture ingress or pests. Sealants specifically identified for the purpose of sealing raceways are designed to create an effective barrier while being safe for the materials with which they come into contact. Choosing materials that do not match or are incompatible with the insulation can jeopardize the performance and safety of the entire electrical system.