Rewiring or upgrading a home’s electrical system is a multi-step process that typically involves assessing the existing wiring, pulling permits, replacing outdated or unsafe wiring with modern cable, upgrading the electrical panel if needed, and passing inspections at each phase. The scope depends on your home’s age, the condition of the existing wiring, and what you’re trying to accomplish — from a targeted upgrade in one area to a whole-house rewire. In Colorado, all electrical work of this nature must be performed by a licensed electrician and inspected by the local authority having jurisdiction (AHJ).

Step 1: Assessment and Planning

A licensed electrician starts by evaluating what you have. In Denver-area homes built before the 1970s, that often means knob-and-tube wiring or early aluminum wiring — both of which carry safety and insurance implications. Homes from the 1970s through 1990s may have aluminum branch-circuit wiring in certain areas, which requires specific remediation at device connections. The assessment covers the panel, service entrance, branch circuits, grounding, and the condition of existing wiring throughout the home.

From there, the electrician develops a scope of work: which circuits need to be replaced, whether the panel needs an upgrade to handle modern load demands, and what GFCI or AFCI protection must be added to bring circuits up to current code. A permit is pulled before any work begins — this isn’t optional, and skipping it can create serious problems when you sell the home or file an insurance claim.

Step 2: Panel Upgrade (If Needed)

Many older Denver homes were built with 100-amp service panels — enough for the appliances of 50 years ago, but insufficient for today’s loads: EV chargers, heat pumps, electric ranges, home offices with multiple workstations, and large HVAC systems. Upgrading to a 200-amp panel (or larger for high-demand homes) is often the first phase of a rewire project. The utility must be coordinated to temporarily disconnect service, the new panel is installed and grounded, and the meter base may be upgraded as well.

Step 3: Branch Circuit Rewiring

The actual rewiring involves running new NM-B (Romex) or conduit-based wiring from the panel to each outlet, switch, and fixture location. In an occupied home, this is done in phases to minimize disruption. Walls may need to be opened in targeted areas, or electricians may use fish tape and flexible drill bits to route wire through wall cavities with minimal drywall damage. Some rooms — kitchens, bathrooms, garages, exterior areas — require GFCI-protected circuits. Bedrooms require AFCI (arc-fault) protection under current code.

  • Kitchen circuits: dedicated 20-amp circuits for appliances, GFCI protection at all countertop outlets
  • Bathroom circuits: GFCI-protected, typically shared but on a dedicated 20-amp circuit
  • Bedroom circuits: AFCI protection required at the breaker in new or rewired circuits
  • Exterior and garage outlets: GFCI-protected, weatherproof covers on outdoor receptacles

Step 4: Inspections and Sign-Off

Colorado requires inspections at rough-in (before walls close) and at final completion. The inspector verifies that all wiring meets the adopted National Electrical Code (NEC) as amended by the state and local jurisdiction. In Denver, the city’s Building and Safety Inspection Division handles residential electrical permits and inspections. Passing final inspection is what officially makes the work legal and documentable for insurance and resale purposes.

How Long Does a Rewire Take?

A targeted upgrade — say, rewiring a single floor or replacing a panel — may take one to three days. A whole-house rewire of a larger older home can take a week or more, depending on construction type and how accessible the wall cavities are. Your electrician should give you a realistic timeline and a clear scope of work before the project starts, along with a firm price so there are no surprises.

Never attempt to rewire branch circuits yourself — this is one area where unlicensed work creates genuine fire and electrocution risk and will void your homeowner’s insurance. Done’s licensed electricians handle panel upgrades and full rewires throughout the Denver metro. Learn more on our panels and wiring page or explore our full range of electrical installation and remodel services.