If you live in an older home, you might have discovered a unique type of electrical wire in a hidden corner: BX cable. This vintage armored cable is a common feature of old houses, but it comes with unique safety concerns. Learning how to identify and properly handle it is crucial for keeping your home safe.
old bx cable
How to Identify Old BX Cable
The most noticeable feature of BX cable is its distinctive flexible metal armor. This outer sheath is typically made of galvanized steel or aluminum, spiraling around the internal wires like a metallic snakeskin. Unlike modern non-metallic cables (like Romex), it doesn't have a smooth plastic jacket.
Another key identifier is its age and grounding method. Old BX cable installed before the 1940s generally lacks a dedicated ground wire. This means its only grounding path is through the metal sheath itself.
Major Safety Concerns with Old BX Cable
When you find old BX cable in your home, be aware of these potential issues:
- Lack of a Reliable Ground: This is the biggest risk. The metal sheath on old BX cable can lose its grounding function due to corrosion, loose connections, or improper installation. This creates a risk of electric shock if an appliance casing becomes energized.
- Deteriorating Insulation: Early BX cable used rubber insulation for its wires. Over time, this insulation becomes brittle, cracks, and can even fall off, exposing bare wires that can lead to short circuits and fires.
- Insufficient Electrical Load: Old BX cable was designed for the low-power electrical needs of a bygone era. Modern home appliances (like microwaves, hairdryers, and computers) can overload these older circuits, causing the wires to overheat and potentially start a fire.
How to Safely Handle Old BX Cable
When dealing with old BX cable, the best course of action is to hire a licensed electrician for a professional assessment.
- If the cable is in good condition with no signs of damage, and no new electrical work is planned, it may be possible to leave it.
- If the cable shows any signs of damage, or you plan to add new circuits, it's strongly recommended that you have it completely replaced with a modern cable that includes a dedicated ground wire (such as Romex or MC cable).
Remember, electrical work is risky. Never attempt to handle or repair old, deteriorating BX cable on your own.
