Rewiring your home's electrical system to increase its capacity can be a complex project, but with proper planning and safety precautions, it's possible for a homeowner to do it themselves without hiring an electrician. In this article, I'll walk through the complete process of rewiring a home electrical system to handle more power, from assessing your current electrical load and service, to installing new wiring, circuits, and electrical panel upgrades.
Assessing Your Current Electrical Service
The first step is to understand your current electrical service and determine if it can handle more capacity or needs upgrading. Here's what to check:
Check Your Electrical Panel
- Open the main electrical panel and look at the main breaker size - this determines the max amps/watts your system can deliver. A 100 amp breaker panel can deliver 24,000 watts, 200 amp can deliver 48,000 watts.
- Count the number of 120V and 240V circuits to understand capacity. Each 120V/15 amp breaker circuit can deliver 1,800 watts. Each 240V/30 amp circuit can deliver 7,200 watts.
- Note if there are open breaker slots to add new circuits. Lack of open slots indicates your panel may be maxed out.
Calculate Electrical Load
- Add up wattages of all lights, appliances, equipment. A laptop is 60W, fridge is 700W. Measure devices or check nameplates.
- Compare total load to your main breaker capacity. If approaching 80-90%, your panel may be underpowered.
Check Voltage Drop
- Turn on high-wattage devices like the AC or electric stove. Use a multimeter to measure voltage at outlets.
- Significant voltage drop under load indicates undersized wiring. Some drop is normal, but above 5% indicates upgrades needed.
If your panel is maxed out and you're seeing voltage drop, your home definitely needs upgraded electrical service for more capacity.
Upgrading Electrical Service
If your current electrical service is inadequate, you'll need to upgrade for more power:
Install New Electrical Panel
- Choose a main breaker panel with extra capacity - 100 amps may need to go to 200 amps. Make sure the amp rating exceeds your calculated electrical load.
- Hire an electrician to install the new, larger electrical panel by the main meter. This often requires new, thicker main wires.
Run New Wire to Circuits
- For high-power 240V circuits like stoves or AC units, run thicker 10 or 8 AWG wire instead of 12 or 14 AWG. Higher gauge wire allows more power flow.
- You can splice into existing wires, or run entirely new home runs from circuits back to panel. Use cable staples/clips to securely attach.
Add 240V Circuits
- Many high-watt appliances like dryers and water heaters use 240V. Hire an electrician to install new 240V circuit breakers in the upgraded panel.
- Run 10/3 or 8/3 NM cable from the panel to the 240V appliance locations. Use thicker 8 AWG for 50 amp+ circuits.
- Install new 240V outlets or direct wire appliances to the cables. Use proper strain relief and wire nuts.
Install Higher Amp Breakers
- Standard wall outlets are usually 15 amp breakers, allowing just 1,800 watts. For high-power devices, install 20, 25, or 30 amp breaker circuits.
- Use 12 AWG wire for 20 amp breakers, 10 AWG for 30 amp breakers. Higher amperage allows more power delivery.
- Label these dedicated circuits clearly in the breaker panel, i.e. “Outlets - 20A”.
Adding More Circuits and Outlets
To increase capacity for multiple devices, add additional standard wall outlet circuits wired with 12 or 14 AWG NM cable:
- Calculate total watts needed. Group compatible devices on shared circuits (15/20 amps).
- Pull cable from breaker panel to outlets. Staple neatly along joists and studs.
- Match wire color to breakers. Black to hot, white to neutral, bare copper to ground.
- At outlets, strip sheathing, insert into boxes, and terminate on receptacles. Follow codes for cable clamps.
- Connect the circuit's ground wire to outlet boxes using pigtails. Maintain ground continuity.
- Label each new circuit clearly. Balance loads across new circuits.
Consider Arc-Fault and GFCI Protection
- For bedroom circuits, consider installing AFCI breakers, which detect dangerous arcs that can start fires.
- Use GFCI outlets in bathrooms, kitchens, wet areas to prevent shocks. GFCIs shut off power rapidly if a ground fault occurs.
- Both options add safety when increasing capacity with more outlets and appliances.
Doing It Safely
Rewiring an electrical panel and running new circuits has risks if not done properly. Follow these safety tips:
- Turn off main breaker and verify power is off before doing any work. Test wires with a non-contact voltage tester.
- Follow local electrical codes for cable gauge, wiring methods, breaker sizes, and outlets. Inspectors will check this.
- Label all wires clearly and update the circuit map in the electrical panel box.
- Ensure outlets and devices are compatible with higher voltage circuits. Use heavy duty commercial grade outlets.
- Hire electricians for complicated work like installing the main panel, running 240V circuits, or connecting wires to the panel.
Rewiring a home electrical system with more power takes planning and care, but following proper guidelines helps ensure success. Adding more circuits, higher amperage breakers, and larger wire allows safe delivery of more electricity to power hungry appliances and devices. Just be sure to calculate your true needs, adhere to codes, and seek experienced help when necessary. With some diligent DIY work, you can upgrade your electrical service to handle the increased loads from modern living without outsourcing the entire project to an electrician.