How to Splice Cloth-Wrapped Wiring

Introduction

Splicing cloth-wrapped wiring is a skill that many homeowners and DIYers need to learn. Cloth-wrapped wiring was commonly used in homes built before the 1960s. Over time, the insulation can become brittle and cracked, necessitating a splice repair. Splicing this type of wiring properly ensures electrical safety and prevents fires or shocks. In this comprehensive guide, I will cover everything you need to know to splice old cloth-wrapped wiring.

Reasons You May Need to Splice Cloth-Wrapped Wiring

There are several common reasons you may need to splice old cloth-wrapped wiring:

• Insulation deterioration - The cloth insulation can become dried out and cracked over many decades. This exposes the inner conductors and creates a shock or fire hazard. Splicing restores the insulation.

• Wiring damage - Old wiring may get damaged due to pests, moisture, or improper handling. This can require cutting out the damaged section and splicing the old wiring.

• Renovations - Upgrading the electrical system or doing renovations often requires splicing existing cloth-wrapped wiring to extend circuits.

• New fixtures - When adding or replacing light fixtures, switches, receptacles, or appliances, you may need to splice the old wiring to make connections.

Supplies Needed

Splicing cloth-wrapped wiring properly requires having the right supplies on hand:

• Wire strippers - A proper wire stripper with adjustments for small and large gauges is important.

• Electrical tape - High-quality electrical tape designed for splicing is a must. Avoid cheap tape.

• Wire nuts - Properly sized wire nuts to match the gauge of the wire are crucial.

• Electrical lubricant - Lubricant makes twisting wires together easier and improves conductivity.

• Heat shrink tubing - Optional but recommended. This tubing seals splices for added insulation.

• Voltage tester - A non-contact voltage tester to confirm the circuit is dead is recommended for safety.

Turn Off Power and Confirm Circuit is Dead

Before splicing any wiring, you must ALWAYS turn off the power at the breaker. Test the wires with a non-contact voltage tester to confirm the circuit is dead. Attempting to splice live wires can result in electrocution. Never take risks when working with electrical wiring.

To be extra safe, I also recommend taping a sign over the breaker switch indicating you are working on the circuit until the job is completed.

Cutting and Preparing the Wiring

With the power confirmed dead, now you can begin splicing:

1. Use wire strippers to cut and remove about 1 inch of the old cloth insulation from each wire end you will be splicing. Take care not to nick or cut into the inner wire.

2. Twist the inner wire strands together tightly and straighten them out. Ensure no stray strands are poking out.

3. Apply a small amount of electrical lubricant to the wires. This will improve conductivity and prevent corrosion.

4. Optional but recommended - Slide a piece of heat shrink tubing over one wire end. This will seal the splice after completion.

Joining and Securing the Wires

With the wire ends prepared, you can join them together:

1. Choose a properly sized wire nut and twist it onto the two prepared wire ends, twisting clockwise. Twist firmly but not excessively.

2. Secure the wire nut tightly onto the wires. Then, tug firmly on each wire to ensure they are tightly joined. The wires should not come loose.

3. Optional - Slide the heat shrink tubing over the wire nut and use a heat gun to shrink it tightly over the splice, sealing it.

4. Use electrical tape to wrap the joint and provide a second layer of insulation. Wrap the tape tightly around the joint overlapping itself.

Restoring Power and Testing

You're almost done! To complete the splice:

1. Carefully restore power at the breaker and turn it back on.

2. Use a voltage tester to re-confirm power is live to the circuit.

3. Turn on lights, switches, or test receptacles to confirm proper operation.

4. A small spark when restoring power is normal. No sparks, flickering lights, or lost power indicate a problem with the splice.

Safety Tips

Follow these safety tips whenever splicing electrical wiring:

• Turn off power - Always turn off power and double check it's dead before splicing.

• No live wiring - Never work on wiring that is still live or hot.

• Disconnect both ends - When possible, disconnect both ends of the wiring you are splicing.

• Match wire size - Wire nuts and splices must match the gauge of the wire.

• Make tight connections - All wire twists and wire nut connections should be tight and secure.

• Insulate properly - Fully cover splices with electrical tape and/or heat shrink tubing.

• Use caution - Wear safety glasses and work cautiously to avoid wire fragments or shocking wires accidentally.

Conclusion

Splicing old cloth-wrapped wiring properly takes care, patience, and the right techniques and supplies. Maintaining the electrical safety of your home's old wiring prevents the risks of shocks or electrical fires. With the steps I have outlined in this guide, you now have the knowledge to tackle splicing those old cloth-wrapped wires like a pro. Be sure to work safely, and don't hesitate to call an electrician if a wiring job is beyond your skill level. Take your time, double check your work, and you can help preserve your home's vintage electrical system for many more decades to come.