What thickness of steel plate is required to protect Type NMC cable installed in shallow chases?

To effectively protect Type NMC cable installed in shallow chases, a thickness of 1/16 inch steel plate is specified. This requirement is established by the National Electrical Code (NEC) to ensure adequate protection against physical damage that could occur during installation or subsequent activities within the chase.

Using a steel plate of this thickness provides a balance between adequate shielding from potential impacts and the ability to install the plate without excessive structural disruption. Thicker plates might be over-engineered for typical residential applications, while thinner options would not provide sufficient protection. Therefore, specifying a 1/16 inch thickness meets the safety and performance requirements for protecting NMC cable in shallow chases effectively.

In contrast to the other thickness options, a 1/4 inch thick plate would likely be unnecessarily heavy and not practical for typical installations, while 1/8 inch and 1/32 inch would not meet the protective standards required for this type of cable.