MC cable is a factory-assembled armored wiring solution used for services, feeders, and branch circuits in indoor and outdoor settings.
Metal-clad cable, usually called MC cable, bundles insulated conductors inside a flexible metal armor that protects the wires without requiring rigid conduit. Electricians reach for it when they need a durable, code-compliant way to run power across exposed surfaces or through concealed spaces. The question of what is MC cable used for comes down to one idea: it delivers power and control signals to everything from residential lighting to industrial machinery.
Where MC Cable Is Approved For Installation
Type MC cable may be used indoors and outdoors, and in exposed or concealed installations when the cable is listed for the application. You will find it carrying power to lighting circuits, feeding subpanels, or running control wiring through commercial buildings.
NEC Article 330 governs how MC cable is used, constructed, and installed. The cable must also meet requirements found in Articles 230 and 300, which cover service entrances and general wiring methods.
Fire-Resistive and Plenum Applications
Some MC cable products are built for fire-resistive or plenum spaces, but these variants follow stricter rules than standard MC. A manufacturer guide identifies traditional Type MC cable as manufactured to UL Standard 1569, while specialty constructions carry additional listings.
Fire-resistive MC cable must be installed exactly as the manufacturer directs, including specific spacing, support, and junction-box transition methods. The product listing controls where each cable can go, not a generic rule that fits every armored cable.
How The Grounding and Bonding Works
MC cable grounds equipment differently than AC cable. For MCI-A constructions, you fold out and cut the bare aluminum grounding conductor flush rather than using the bonding strip-back method common with AC cable.
The NEC-recognized grounding approach may rely on the armor plus a bond wire for certain constructions. This is why mixing installation methods between cable types causes problems, and why the grounding conductor handling differs by construction.
Key Installation Steps Per Manufacturer Guidance
Southwire’s installation guide states MC cable must meet NEC requirements. The correct process starts with selecting a listed MC connector sized for the cable and its application, then removing the required armor length with an appropriate cutting tool.
The cable must insert fully so the armor does not extend past the connector end stop. Secure the connector to the box or enclosure, then terminate the conductors per the product instructions. A common mistake is using a connector not listed for the specific MC construction, which creates a compatibility problem. Never assume every MC cable works everywhere, because listing, marking, and NEC article conditions control where it is allowed.
| Application | What It Does | Key Requirement |
|---|---|---|
| Services and feeders | Brings power from the service point to distribution panels | UL 1569 and NEC compliance |
| Branch circuits | Feeds lighting, receptacles, and appliances | Listed connector for the construction |
| Control and signal circuits | Carries power and control voltage in one cable | All conductors insulated for highest voltage |
| Exposed installations | Runs along walls or ceilings without conduit | Proper supports and fittings |
| Plenum or fire-resistive spaces | Maintains circuit integrity during a fire | Product-specific installation guide |
| Hazardous locations | Used only with specific listings | Cable marked for the location class |
Hazardous locations require MC cable listed and marked specifically for that use.
For a feeder to a garage subpanel or the branch circuit feeding a workshop, it performs like a workhorse. If you are planning a project and need to compare options, our 10 3 MC cable recommendations sorts through tested choices for heavier loads.
The outer metal jacket handles physical protection, while the internal conductors stay flexible enough to route around obstacles. That combination is why you see it in commercial buildings, parking garages, and industrial plants where exposed wiring must survive contact and stay code-legal.
FAQs
Can MC cable be buried directly in the ground?
Standard MC cable is not rated for direct burial. Underground installations require cable types listed for wet locations and direct earth contact, such as UF cable or conductors in rigid conduit. Some MC products carry wet-location listings for outdoor exposed runs above grade, but the listing must explicitly permit the installation method.
Does MC cable require a separate ground wire?
It depends on the construction. Some MC cable relies on the armor combined with an internal bond wire for equipment grounding, while other constructions include a full-size grounding conductor. The cable’s markings and listing indicate the recognized grounding method. Your local electrical inspector applies the NEC rules for the specific cable type installed.
Is MC cable the same as armored cable?
MC cable and AC cable are both armored, but they are different products with different rules. AC cable uses an internal bonding strip and lacks a dedicated grounding conductor in some constructions. MC cable typically includes a grounding conductor and follows NEC Article 330, while AC follows Article 320. The installation methods for grounding do not interchange.
References
- Southwire. “MC Cable Installation Guide.” Details NEC requirements and proper connector and termination procedures.
- NEMA. “Bulletin No. 112: Selection and Installation of Type MC-PCS Cable.” Covers dual-voltage applications and insulation requirements.
- Encore Wire. “MC Cable Guide Specification.” Lists UL and federal standards for Type MC cable.
