Chapter 7, Problem 1R

Is it permissible to install a recessed luminaire directly against wood ceiling joists when the label on the luminaire does not indicate that the luminaire is suitable for insulation to be in direct contact with the luminaire? This is a Type Non-IC fixture.

To determine

Find whether the recessed luminaire is permitted to directly install against a wood ceiling joist when the label on the luminaire does not indicate that it can be used for insulation in contact with the recessed luminaire.

Answer to Problem 1R

No, the recessed luminaire is not permitted to directly install against a wood ceiling joist when the label on the luminaire does not indicate that it can be used for insulation in contact with the recessed luminaire.

Explanation of Solution

Discussion:

The National Electrical Code committee develops NEC – the standard electrical code and the main objective for the origin of the code is to protect and safeguard the person and elements from electrical hazards. The codes for clearance and installation of luminaire are defined in an article NEC 410.116.

According to an article NEC 410.116(A)(1), for Non-Type Insulated Contact(IC), the recessed luminaire which is not identified for the contact with the insulation should have recessed parts that are spaced not less than $13\text{mm}\left(\frac{1}{2}\text{in}\right)$ from the combustible materials.

The trim finishing and points of support of the openings in the walls, ceilings, or the other finished surfaces are allowed to be in contact with the combustible materials. Therefore, the recessed luminaire is not permitted to directly install against the wood ceiling joists when the label is not indicated on the luminaire.

Conclusion:

Thus, the recessed luminaire is not permitted to directly install against a wood ceiling joist when the label on the luminaire does not indicate that it can be used for insulation in direct contact with the recessed luminaire.