Why Rewiring Your Home Can Be Dangerous
Rewiring a home can be extremely dangerous if proper safety precautions are not taken. Electricity poses significant risks, including electrocution, burns, fires, and equipment damage. Home electrical systems carry high voltage and amperage that can easily kill or seriously injure. However, with proper planning, protective equipment, and adherence to electrical safety procedures, the risks can be minimized.
Main Electrical Hazards
When rewiring a home, the main hazards to avoid are:
- Electrocution - Contact with live wires or components can result in severe shock or death. As little as 50V can be fatal under certain conditions.
- Arc flashes - Short circuits can create explosive electrical arcs with intense heat capable of causing severe burns.
- Fire - Faulty wiring can overheat and ignite nearby combustible materials. Electrical fires are extremely dangerous.
- Equipment damage - Power surges can destroy appliances, electronics, and other electrical equipment.
How Electrical Shock Occurs
Electric shock occurs when a person becomes part of an electrical circuit, causing current to flow through their body. This disrupts the body's normal electrical signals, which can affect critical organs like the heart.
There are several ways a person can become part of an electrical circuit and get shocked:
- Direct contact - Touching exposed live conductors or components.
- Indirect contact - Touching something electrically energized that shouldn't be, like a metal appliance chassis.
- Step potential - Current flows from one foot to the other through the body.
- Touch potential - Current flows from the hands through the body to the feet.
Factors Affecting Shock Severity
The severity of an electrical shock depends on several key factors:
- Amount of current flow - Measured in amperes (A). The more current, the more dangerous. As little as 0.01A can be fatal.
- Pathway through body - Current crossing the heart is most hazardous.
- Duration of exposure - Longer exposure results in worse effects.
- AC vs DC - AC is generally more dangerous than DC at the same voltage.
- Frequency - Higher frequency AC is more dangerous.
- Skin conditions - Sweaty or wet skin reduces body resistance.
Safety Gear to Wear
Rewiring a home safely requires wearing proper protective gear and being prepared for unexpected situations. At minimum, you should wear:
- Provide protection against accidental contact with live conductors.
- Must be designed for electrical work. Regular gloves can ignite or melt.
- Should be inspected for damage before each use.
- Tested regularly per ASTM standards.
- Safety glasses or face shield to prevent arc flash burns.
- Side shields recommended for maximum protection.
- Prevent step potential shocks through the feet.
- Ensure soles are unconductive and oil resistant.
- Check for cracks in soles or damage.
- Tested to meet ASTM electrical hazard standards.
Flame Resistant Clothing
- Long sleeves/pants provide arc flash protection.
- Materials like cotton better than synthetics.
- No polyester, nylon, rayon which can melt.
- Hard hat protects from falling objects or electrical arcs.
- Face shield for facial protection.
Safe Electrical Work Procedures
Follow these procedures to perform electrical work safely:
De-energize and Lock Out/Tag Out
- Turn off power at breaker/fuse box and verify it is off.
- Engage lock out/tag out devices to prevent accidental re-energization.
- Check for dangerous backfeed or feedback voltage.
Establish Proper Work Zone
- Clear area of slip/trip hazards and flammable materials.
- Allow adequate workspace for activity.
- Restrict access to qualified personnel only.
Insulate Exposed Parts
- Cover/block live components that cannot be de-energized.
- Install protective barriers as needed.
Use Insulated Tools
- Non-conductive hand tools prevent direct contact.
- Tools should be regularly tested and rated for purpose.
Minimize Energized Work
- Only work live when absolutely necessary.
- Have experienced spotter oversee work.
- Use properly rated equipment and PPE.
Work in Pairs
- Second person can shut off power or provide aid in emergency.
- Avoid distractions which can lead to accidents.
- Take breaks to maintain concentration.
How to Rewire a Home Room by Room
Rewiring a house is a major project that requires careful planning and execution. It's safest and most efficient to rewire one room at a time. Here is the basic process:
1. Turn Off Power
Shut off the main breaker/fuse for the room you'll be working in. Verify power is off with a contactless voltage tester.
2. Remove Old Wiring
Take down existing wires, outlets, switches, and junction boxes. Properly dispose of old electrical components.
3. Plan New Wiring
Map out new circuit routes and devices. Consider additional circuits, grounded outlets, lighting needs, etc.
4. Install New Wiring and Boxes
Run new NM cables and install junction boxes and mounting brackets where required.
5. Connect Devices and Outlets
Connect wires to devices like switches, outlets, and fixtures. Secure them to boxes.
6. Turn Power Back On
Restore power at the breaker and test operation. Check for faults.
7. Finish Surfaces
Patch over holes and refinish walls, ceilings, etc. to match old surfaces.
Follow this basic sequence for each room. Pay close attention to electrical safety procedures throughout the process.
Tips for Safe Rewiring
- Shut off power at the breaker before starting any work.
- Wear insulated gloves and eye protection.
- Use GFCI outlets or breakers for added protection.
- Label all wires and take photos before dismantling.
- Mount junction boxes securely and use cable clamps.
- Avoid overloading circuits with too many devices.
- Use the proper wire gauge for the amperage rating.
- Connect ground wires to all devices.
- Organize wires neatly inside boxes without kinks.
- Secure cables every 4.5 ft with staples/straps.
- Caulk around boxes to prevent fire spread.
- Cover all junction boxes and exposed wires.
- Take frequent breaks when doing live testing.
- Get permits and have work inspected as required.
Warning Signs of Electrical Problems
While rewiring, watch for any of these warning signs of faulty wiring:
- Unusual odors - burning smell may indicate overheating.
- Discolored wires - melted insulation exposes copper.
- Warm outlets or cords - overcurrent causes heat buildup.
- Flickering lights - loose connections interrupt flow.
- Buzzing/crackling from outlets - arcing due to faulty wiring.
- Frequent tripped breakers - overloads or short circuits.
- Tingling feeling - sign you may be getting shocked.
- Blackened receptacles - evidence of overheating.
If you notice any of these, turn off power and thoroughly inspect connections. Faulty wiring can't be ignored and should be repaired by a qualified electrician.
When to Call a Professional
While do-it-yourselfers can perform basic electrical repairs, it's safest to call a licensed electrician for:
- Major rewiring jobs.
- Upgrading the main service panel.
- Installing new circuits and subpanels.
- Rewiring old, outdated electrical systems.
- Running wiring through finished walls/ceilings.
- Meeting building codes and permit requirements.
Hire a qualified electrician any time you feel unsure about performing a task safely. They have the proper tools, training and expertise to handle hazardous electrical work.
Rewiring a home has serious risks if safety rules aren't followed. With careful planning, the right protective gear, and proper procedures, you can minimize hazards and complete a successful, code-compliant rewiring project safely. Pay close attention to warning signs and don't hesitate to call a professional electrician when needed.