No, generally speaking, MC cable cannot be run horizontally in the grooves of the outside metal behind vertical structural braces in a manner that relies solely on those grooves for support and protection. Here's why: Lack of Adequate Support and Protection

The grooves are not specifically designed or approved as a wiring method or a support for MC cable. They might not provide:

Secure Support

The MC cable needs to be properly supported and secured at intervals specified by the NEC (National Electrical Code). The grooves are unlikely to provide consistent and code-compliant support.

Physical Protection

The grooves may not protect the MC cable from physical damage. MC cable is already designed to be rugged, but it still needs protection from potential impacts, abrasions, or other mechanical stresses.

NEC Requirements for MC Cable Support

The NEC (specifically Article 330 regarding MC cable) has specific requirements for how MC cable must be supported and secured. These requirements usually involve using straps, cable ties, or other listed methods.

Potential for Damage

Routing MC cable in a tight groove could potentially damage the outer jacket of the cable over time due to vibration, expansion/contraction, or other factors.

Workmanship

Such an installation would generally be considered poor workmanship and likely to be flagged during an electrical inspection.

Acceptable ways to install MC

Use cable ties to secure the MC cable to the structural braces. Use cable straps and screw them into the metal.* Use J-hooks to hang the MC cable.

Always consult the NEC and local codes. Always consult with a qualified electrician to ensure your electrical installation is safe, compliant, and meets all applicable codes. Flag for review