Extend Electrical to New Space
Your home addition needs proper electrical service to function safely and meet code. This step covers outlet placement, circuit requirements, GFCI/AFCI protection, and whether your existing panel can handle the additional load.
Quick Summary
Typical cost
$2,000-$8,000
Time needed
2-4 days
Professional help
Licensed electrician
Why This Step Matters
Electrical work isn't just about having lights and outlets—it's about safety. Improper wiring is a leading cause of house fires, and code violations can derail your final inspection. Modern electrical codes require specific outlet spacing, dedicated circuits for certain rooms, and arc-fault/ground-fault protection throughout.
Common Mistake
Many homeowners underestimate their panel capacity. If your existing panel is 100 amps and already heavily loaded, adding a 400+ sq ft addition often requires a panel upgrade to 200 amps—adding $1,500-$3,000 to your project.
Electrical Code Requirements
Outlet Spacing: Every 12 Feet
The NEC (National Electrical Code) requires that no point along a wall be more than 6 feet from an outlet. In practical terms, this means outlets every 12 feet along walls, plus outlets on any wall section wider than 2 feet.
Kitchen counters: Require outlets every 4 feet and within 2 feet of any countertop edge. All kitchen counter outlets must be GFCI protected.
GFCI Protection (Ground Fault)
GFCI outlets prevent electrocution by detecting ground faults and cutting power within milliseconds. They're required in:
- Bathrooms (all outlets)
- Kitchens (countertop outlets within 6 feet of sink)
- Laundry areas
- Garages and unfinished basements
- Outdoor outlets
AFCI Protection (Arc Fault)
AFCI breakers detect dangerous electrical arcs that can cause fires. The 2020 NEC requires AFCI protection for virtually all living spaces including:
- • Bedrooms (required since 1999)
- • Living rooms and family rooms
- • Dining rooms
- • Hallways and closets
- • Home offices and dens
Note: AFCI breakers cost $30-$50 each vs. $5-$10 for standard breakers, but they significantly reduce fire risk from faulty wiring.
Dedicated Circuits
Certain appliances require their own dedicated circuits that serve only that appliance:
- • Refrigerator: 20-amp dedicated circuit
- • Dishwasher: 15 or 20-amp dedicated
- • Garbage disposal: 15 or 20-amp (can share with dishwasher)
- • Microwave: 20-amp dedicated
- • Bathroom: 20-amp dedicated (can serve multiple bathrooms)
- • Electric dryer: 30-amp 240V dedicated
- • Electric range: 50-amp 240V dedicated
Does Your Panel Need an Upgrade?
Your electrical panel has a maximum capacity measured in amps. Adding circuits for a new space increases demand on this panel. Here's how to evaluate:
| Current Panel | Addition Size | Likely Need |
|---|---|---|
| 100 amp | < 300 sq ft | May be OK if panel has spare capacity |
| 100 amp | 300-600 sq ft | Upgrade to 200 amp likely needed |
| 100 amp | > 600 sq ft | 200 amp upgrade required |
| 200 amp | Any typical addition | Usually sufficient |
Electric car chargers, hot tubs, or all-electric HVAC increase panel requirements significantly.
Cost Breakdown
Basic Electrical (No Panel Upgrade)
- • Rough-in wiring: $1,000-$2,500
- • New circuits (5-10): $500-$1,500
- • Outlets and switches: $200-$500
- • Light fixtures: $300-$1,000
- Total: $2,000-$5,500
With Panel Upgrade
- • 200 amp panel upgrade: $1,500-$3,000
- • Utility coordination: $200-$500
- • Permit fees: $150-$400
- • Basic electrical (above): $2,000-$5,500
- Total: $4,000-$9,400
Frequently Asked Questions
Can I extend electrical myself to save money?
In most jurisdictions, homeowners can do their own electrical work, but it still requires permits and inspections. However, for a permitted addition with multiple circuits, most inspectors will scrutinize DIY work heavily. Mistakes can fail inspection or cause fires. We strongly recommend licensed electricians for additions.
How many outlets do I need per room?
Code requires outlets every 12 feet along walls, but plan for more based on furniture layout. Bedrooms typically need 6-8 outlets, living areas 8-12, and home offices may need 10+ to accommodate equipment. Adding outlets during rough-in costs about $50-$100 each; adding them later costs $200-$400.
What wire gauge is required?
Standard 15-amp circuits use 14-gauge wire; 20-amp circuits require 12-gauge. Heavy-duty 30-amp circuits (like dryers) need 10-gauge, and 50-amp circuits (like ranges) need 6-gauge. Your electrician will size wire appropriately for each circuit's load.
Should I plan for an EV charger?
Yes, if there's any chance you'll own an electric vehicle within 10 years. Running a 240V 50-amp circuit to your garage during construction costs $300-$500. Adding it later can cost $1,000-$2,500 depending on panel capacity and wire runs.
Ready for the Next Step?
With electrical rough-in complete, the next step is running plumbing for any bathrooms in your addition. Coordinate with your electrician and plumber to avoid routing conflicts.