How to Replace Two-Prong Outlets in an Old House

Introduction

Replacing two-prong outlets in an old house with grounded three-prong outlets can greatly improve safety and allow the use of modern appliances. However, working with electrical wiring requires knowledge and caution to avoid hazards. This guide will walk through the complete process of replacing two-prong outlets with three-prong outlets in an old house.

Reasons to Upgrade to Three-Prong Outlets

There are several benefits to upgrading outlets in an old house from two-prong to three-prong:

Safety - Two-prong outlets lack a ground wire which is essential for safe operation of modern appliances and preventing shocks. Three-prong outlets provide grounding.
Appliance Compatibility - Many modern appliances like computers, TVs, and kitchen appliances require a three-prong grounded outlet to plug in safely. Two-prong outlets limit what you can use.
Electrical Capacity - Three-prong outlets allow grounded 15 amp and 20 amp circuits. This provides more power capacity for running multiple and larger appliances.
Resale Value - Upgraded electrical improves home value. Grounded three-prong outlets meet modern safety standards.

Evaluating the Existing Electrical System

Before replacing two-prong outlets, you need to assess the existing electrical system to understand how to properly upgrade. Consider the following:

Age of wiring - Old cloth-wrapped wiring has degradation risks. Newer rubber/plastic insulated wiring is safer.
Circuit breaker box - An up-to-date grounded circuit breaker box is essential for three-prong outlets to be compliant. Old fuse boxes need replacement.
Grounding wire - Check if a ground wire is present. If not, running new ground wires involves more work.
Electrical load - Consider if circuits have adequate capacity for running heavier loads with 3-prong outlets.

Consult an electrician if the electrical system needs significant upgrades beyond just swapping outlets.

Gathering the Right Replacement Outlets & Supplies

Make sure you have the correct materials available before starting outlet replacement:

Three-prong outlets - Buy new 15 amp or 20 amp rated three-prong outlets that match the circuit capacity and design aesthetic.
Pigtails - Get 12 or 14 gauge insulated copper ground pigtails to connect ground wires.
Wire strippers - A proper wire stripper makes stripping insulation easy.
Voltmeter - A non-contact voltmeter pen can detect live wires to avoid shocks.
Screwdrivers - Have Phillips and flat head screwdrivers available.
Wire nuts - Properly joining copper wires requires anti-oxidant wire nuts.
Electrical tape - Use it to insulate wire connections.
Safety gear - Wear insulated gloves and eye protection when doing electrical work.

Turning Off the Power

Before touching any electrical connections, turn off power to the circuit you're working on at the main circuit breaker panel.

Identify the circuit - Note which breaker controls the two-prong outlets you want to replace.
Switch off breaker - Flip the breaker switch to fully off position.
Confirm power is off - Test outlets with a voltmeter or by plugging in a lamp to check the power is off.

Working on outlets with live power still flowing risks getting a serious shock. Always triple check the power is OFF before proceeding.

Removing the Existing Two-Prong Outlets

With the power safely disconnected, you can now remove the old outlets:

Unscrew mounting screws - Unscrew the top and bottom screws mounting the outlet in the electrical box.
Detach wires - Carefully detach the hot and neutral wires coming from the outlet. Note wire placements.
Remove outlet - Pull the outlet out of the electrical box once the screws and wires are detached.
Inspect box - Check for any signs of damage or wear on the electrical box itself. Replace if needed.
Check wires - Ensure the existing wires are in good shape. Fraying or cracked insulation indicates replacement wiring is needed.

Installing New Three-Prong Outlets

Follow these steps to install each new three-prong outlet:

Connect ground wire - Attach the copper ground pigtail to the green ground screw on the outlet.
Connect hot and neutral - Match the corresponding hot and neutral wires to the brass and silver screws, usually colored red for hot and white for neutral.
Secure outlet - Tighten the mounting screws to secure the outlet firmly in the electrical box.
Test fit cover plate - Attach the decorative outlet cover plate to ensure it fits properly.
Label circuit - Note the circuit number on the back of the outlet for easier identification.

Take care not to overtighten wire connections or screw terminals. A loose wire can cause dangerous arcing.

Restoring Power and Testing

Once you've safely installed all the new three-prong outlets:

Turn circuit breaker back on - Flip the breaker switch to the on position to restore power.
Test each outlet - Plug in a lamp or voltmeter and verify proper operation of each new three-prong outlet.
Check grounding - Test that ground connection works at each outlet using a circuit tester with ground indication.
Connect appliances - Plug in and turn on appliances to confirm normal operation.

Turn off power again immediately if any issues are detected and recheck connections. Safety first!

Conclusion

While replacing two-prong outlets requires working carefully with electrical wiring, the upgrade to modern three-prong grounded outlets is absolutely worth the safety and functionality benefits. Carefully following proper precautions and procedures will ensure the process goes smoothly. Take your time and don't hesitate to consult an electrician if any concerns arise.