Okay, let's break down the proper and code-compliant way to extend your BX cable in your garage.

The Correct and Code-Compliant Method

The only code-compliant and safe way to extend a BX cable is by using a junction box. You cannot simply wire nut and tape connections inside the wall cavity or without a proper enclosure.Here's a step-by-step guide:1.

Safety First: Turn Off the Power! Locate the circuit breaker that controls the light fixture you're working on and switch it to the "OFF" position. Double-check with a non-contact voltage tester to ensure the wires are de-energized. Safety is paramount.2. Prepare the Existing BX Cable

Carefully cut the existing BX cable at a convenient point where it will reach inside the junction box you'll be installing. Remove the outer metal armor of the BX cable, exposing the wires inside. Use a BX cutter or a hacksaw carefully. Be careful not to nick the insulation of the wires. Install an anti-short bushing (red head) on the end of the BX cable to protect the wires from the sharp edges of the cut armor.3.

Install the Junction Box

Choose a metal junction box appropriate for the gauge of wire you're using (usually a standard 4" square or octagon box is fine). Securely mount the junction box to a stud or solid surface near the existing BX cable. Use appropriate screws or nails for the material you're mounting to. The box must be securely supported.4.

Prepare the New BX Cable

Measure the distance from the junction box to the light fixture. Add a little extra length for working inside the box. Cut the new BX cable to the required length. Remove the outer metal armor of the new BX cable, exposing the wires inside. Install an anti-short bushing (red head) on the end of the BX cable.5.

Connect the BX Cables to the Junction Box

Use appropriate BX cable connectors (also called "cable clamps" or "Romex connectors" even though you're using BX). These connectors are specifically designed to secure the BX cable to the junction box and provide strain relief. They prevent the cable from being pulled out of the box and damaging the connections. Insert the existing and new BX cables into the junction box through the cable connectors. Tighten the connectors securely to clamp the cables in place.6.

Make the Wire Connections

Inside the junction box, connect the wires from the existing and new BX cables using appropriately sized wire connectors (marrettes/wire nuts).

Important

Connect like colors to like colors: Black (hot/live) to Black White (neutral) to White Bare copper (ground) to Bare copper (or green if the new BX cable has a green ground wire). Ensure the wire nuts are twisted on tightly and securely. Optionally, you can wrap electrical tape around the wire nuts for added security, but this is not a substitute for properly tightening the wire nuts.7.

Grounding

The metal junction box must be grounded. Connect the bare copper (ground) wires from both BX cables together inside the box. Use a short "pigtail" of bare copper wire to connect the ground wires to a grounding screw inside the metal junction box. This ensures the box itself is grounded.8.

Neatly Arrange Wires

Carefully tuck the wires and wire nuts neatly inside the junction box. Avoid overcrowding the box.9.

Install a Cover Plate

Install a blank cover plate on the junction box. The cover plate must be securely fastened.10.

Restore Power

Turn the circuit breaker back to the "ON" position.11.

Test

Test the light fixture to ensure it's working correctly.

Why is a Junction Box Required? Safety

The junction box provides a fire-resistant enclosure for the wire connections. If a short circuit or other fault occurs, the box will contain the heat and sparks, preventing a fire from spreading.

Protection

The box protects the wires and connections from physical damage, moisture, and dust.

Accessibility

The junction box provides access to the connections for future inspection, maintenance, or repairs. Connections hidden inside walls are inaccessible and violate code.

Code Compliance

Electrical codes (NEC in the US, CEC in Canada, and similar codes worldwide) require all wire splices and connections to be made inside approved junction boxes.

What You Cannot Do (and Why)



Wire Nuts and Tape Alone

This is a fire hazard and a code violation. The tape can dry out and fail over time, exposing the bare wires. The connection is not protected from physical damage or moisture.

Wire Nuts, Tape, and Burying in the Wall

This is even worse. It's a fire hazard, a code violation, and makes future repairs impossible. Hidden connections are extremely dangerous.

Using a Plastic Box for BX

While plastic boxes can be used in some situations, they're generally not appropriate for BX cable. The grounding of BX relies on the metal armor, and the metal box provides a more secure and reliable grounding path.

Important Considerations



Local Electrical Codes

Always check your local electrical codes and ordinances. They may have specific requirements or restrictions that you need to follow. It's always best to consult with a qualified electrician if you're unsure about anything.

Wire Gauge

Use the same gauge wire for the extension as the existing wiring. Using a smaller gauge wire can overload the circuit and create a fire hazard.

Amperage Rating

Ensure the wire connectors and junction box are rated for the amperage of the circuit. Your electrician can help you determine this.

Aluminum Wiring

If your existing wiring is aluminum, you must use connectors and procedures specifically approved for aluminum wiring. Connecting copper to aluminum directly can cause corrosion and create a fire hazard. Consult an electrician.*

Garage Environment

Garages can be damp or dusty environments. Consider using a weatherproof junction box if moisture is a concern.

In Summary:

Extending BX cable requires a junction box, proper connectors, and careful wiring. It's a task that should be approached with caution and a thorough understanding of electrical safety and codes. If you're not comfortable working with electricity, hire a qualified electrician. It's always better to be safe than sorry when dealing with electrical wiring. Flag for review