Wiring armored cable (AC cable), also known as BX cable, involves several steps to ensure a safe and code-compliant electrical connection. Here's a breakdown of the process:
1. Safety First!
- Turn off the power: Always de-energize the circuit at the breaker box before starting any electrical work. Use a non-contact voltage tester to verify the circuit is off.
- Wear appropriate safety gear: Safety glasses and gloves are recommended.
2. Gather Your Materials and Tools:
- Armored Cable (AC Cable): Determine the correct gauge (wire size) and number of conductors based on the circuit's requirements. 14/2 and 12/2 are common sizes.
- Junction Box: A metal or plastic box to house the electrical connections. Ensure it is properly sized for the number of wires and devices.
- AC Connector: Specifically designed for armored cable. These connectors secure the cable to the junction box and protect the wires. Choose the correct size for your AC cable.
- Anti-Short Bushings (Redheads): Plastic bushings to protect the wires from the sharp edges of the cut armor.
- Wire Connectors (Wire Nuts): To connect the wires together inside the junction box.
- Grounding Pigtail (if needed): A short length of wire to connect the equipment grounding conductor (bare wire) to the metal junction box, if required by local code.
- Tools:
- Armored Cable Cutter (Roto-Split or similar) or Hacksaw
- Screwdrivers (slotted and Phillips)
- Wire Strippers
- Pliers
- Non-Contact Voltage Tester
- Tape Measure
3. Measure and Cut the Armored Cable:
- Measure the required length: Determine the distance between the power source and the device you are wiring, plus some extra length for connections (at least 6-8 inches at each end).
- Cut the cable:
- Using an Armored Cable Cutter (Roto-Split): This is the preferred method. Follow the tool's instructions to score the armor. Then, flex the cable at the score to break the armor.
- Using a Hacksaw: Carefully score the armor, being very careful not to cut into the wires inside. Only cut through one layer of the armor. Flex the cable at the score to break the armor.
4. Prepare the Cable End:
- Remove the excess armor: After scoring and breaking the armor, carefully unwind and remove the excess portion. You should be able to twist it off, leaving the wires exposed.
- Install an Anti-Short Bushing (Redhead): Insert the red plastic bushing between the armor and the wires. This protects the wires from abrasion against the sharp cut edge of the armor, preventing shorts.
- Strip the wire ends: Use wire strippers to carefully remove the insulation from the ends of the wires, exposing about 1/2 to 3/4 inch of bare wire.
5. Connect the Cable to the Junction Box:
- Insert the cable into the AC connector: Slide the cable into the connector, ensuring the anti-short bushing is fully seated inside the connector.
- Secure the AC connector to the cable: Tighten the screws on the AC connector to securely grip the armored cable.
- Install the AC connector into the junction box: Insert the connector into the appropriate knockout hole in the junction box and tighten the locknut to secure it. The connector should be firmly attached to the box.
6. Make the Wire Connections:
- Identify the wires: Typically, AC cable contains a black (hot), white (neutral), and a bare copper (ground) wire. However, always confirm the wiring configuration.
- Connect the wires: Use wire connectors (wire nuts) to connect the wires to the corresponding wires from the power source or device. Twist the wires together tightly before screwing on the wire nut. Ensure the wire nut is securely tightened.
- Grounding: Connect the bare copper ground wire to the ground terminal in the junction box and to the grounding screw on the device you are wiring (e.g., outlet, light fixture). If the junction box is metal and local code requires it, use a grounding pigtail to connect the ground wire to the box.
7. Secure the Wires and Close the Junction Box:
- Carefully arrange the wires: Tuck the wires neatly inside the junction box, ensuring they are not pinched or strained.
- Install the cover plate: Securely attach the cover plate to the junction box.
8. Test the Circuit:
- Turn on the power: Go back to the breaker box and turn the circuit breaker back on.
- Test the device: Verify that the device you wired is functioning correctly. Use a multimeter or other appropriate testing device to confirm proper voltage and polarity.
Important Considerations:
- Local Electrical Codes: Always follow local electrical codes and regulations when wiring armored cable. These codes may vary and are designed to ensure safety.
- Permitted Uses: Be aware that AC cable has specific permitted uses. For example, it is generally suitable for dry locations. Check local codes for specifics.
- Professional Help: If you are uncomfortable working with electricity, hire a qualified electrician to do the work.
