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Home Rewiring and Old Wiring Repair in Sacramento

Rewiring replaces old wiring, such as knob-and-tube or aluminum branch circuits, with modern grounded cable. It's a permit job, and national guides put a whole-house rewire at about $7,300 to $13,300 for a 2,200-square-foot home. Not every older home needs a full rewire; targeted repairs or GFCI upgrades may be enough. Call (916) 712-7030 to reach an independent local electrician.

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Does my house need rewiring?

Condition matters more than age. The CPSC warns that failing connections often give little warning, so get an inspection if you notice any of these:

  • Outlet or switch plates that feel warm
  • Flickering lights or circuits that stop working
  • A burning plastic smell near outlets or switches
  • Brittle or cracked insulation where wires are visible
  • Knob-and-tube or aluminum wiring that's never been evaluated
  • Two-prong outlets throughout the house
  • Breakers that trip often

Is knob-and-tube wiring dangerous?

It isn't automatically dangerous, but it's obsolete. InterNACHI says knob-and-tube wiring was common from about 1880 to the 1940s, has no ground wire, and becomes a hazard with age, amateur changes, and insulation packed around it. It was designed to shed heat into open air, so burying it in attic insulation is a fire risk.

Insurance can be the deciding factor. InterNACHI notes that many insurers refuse to cover houses with knob-and-tube wiring unless an electrical contractor says the system is safe. If you're adding insulation or buying an older home, have it evaluated first.

What should I do about aluminum wiring?

Get it checked. The CPSC says homes wired with aluminum before 1972 were 55 times more likely to have an outlet connection reach fire hazard conditions than copper-wired homes. Aluminum shows up in some homes wired from 1965 to the mid-1970s. Look for AL or ALUMINUM printed on the cable jacket in an attic or garage.

The CPSC recognizes three permanent fixes: replacing the aluminum with copper, the COPALUM crimp repair, or AlumiConn connectors. It strongly recommends hiring a qualified electrician for this work.

Are two-prong outlets safe?

They work, but they have no ground wire. This Old House explains that without a ground, a worn wire touching a metal appliance case can make it shock someone, and grounding also helps protect electronics.

The code gives three ways to replace them. An electrician can install another two-prong outlet, install a GFCI outlet marked No Equipment Ground, or install a three-prong outlet that's GFCI-protected and marked both GFCI Protected and No Equipment Ground, according to EC&M's review of the National Electrical Code. Running a new ground wire is the more complete fix.

How much does it cost to rewire a house?

National guides vary. Fixr estimates $7,286 to $13,257 to rewire a 2,200-square-foot home (2025). This Old House puts rewiring at $6 to $10 per square foot, or $9,000 to $15,000 for 1,500 square feet (2026). These are national figures, not Sacramento quotes.

Access drives the price. Homes with open attics or crawlspaces are usually easier to run new wire through than homes with finished ceilings everywhere, and drywall patching and painting are often extra.

What code rules apply when old wiring is updated?

Rewiring needs a permit from your local building department. California's 2025 Electrical Code, in effect since January 1, 2026, adopts the 2023 National Electrical Code with state amendments. Under that code, extending, modifying, or replacing 120-volt circuits in rooms like bedrooms, kitchens, and living rooms generally requires arc-fault (AFCI) protection, and kitchens, bathrooms, laundry areas, garages, and outdoor outlets need GFCI protection.

What wiring to expect by the era a home was built
Era builtWhat you may findSource
About 1880 to the 1940sKnob-and-tube wiring with no ground wireInterNACHI
Before 1965Fuse panels instead of breakersESFI
1950s to mid-1980sSplit-bus panels with no single main breakerInterNACHI
1965 to mid-1970sPossible aluminum branch wiringCPSC
Before about 1972No GFCI outlets (first receptacle type in 1972)ESFI
Before 1999No AFCI breakers (first required in the 1999 NEC)ESFI

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Frequently asked questions

Can I add GFCI outlets instead of rewiring?
For two-prong outlets, often yes. A GFCI outlet adds shock protection without a ground wire, and the code allows it as a replacement when it's labeled No Equipment Ground. It won't fix brittle insulation, aluminum connections, or overloaded circuits, though, and it doesn't give sensitive electronics a ground. An electrician can tell you which problems a GFCI solves and which need new wire.
Will insurance cover a house with knob-and-tube wiring?
It depends on the insurer. InterNACHI says many insurance companies refuse to cover houses with knob-and-tube wiring because of fire risk, though some make exceptions when an electrical contractor deems the system safe. If you're buying an older Sacramento home, ask your insurer early and get an electrician's evaluation before closing.
Is it safe to put insulation over old wiring?
Not over knob-and-tube. InterNACHI says that wiring was designed to release heat into open air, and the insulation wrapped around it becomes a fire hazard. Have an electrician check the attic and walls before an insulation job, especially in a home built before about 1950, when knob-and-tube was still common.

Available across the Sacramento area

Sources

  1. Repairing Aluminum Wiring (Publication 516) — U.S. Consumer Product Safety Commission
  2. Knob-and-Tube Wiring — InterNACHI
  3. Replacing Two-Prong Receptacles — This Old House
  4. Stumped by the Code? NEC Requirements When Replacing Nongrounding-type Receptacles — EC&M
  5. Average Costs to Wire a House (updated January 31, 2025) — Fixr
  6. How Much Does an Electrician Cost? (updated June 5, 2026) — This Old House
  7. The 2025 California Electrical Code, Title 24 Part 3 (based on the 2023 National Electrical Code) — California Building Standards Commission
  8. 2025 Triennial Edition of Title 24 (effective January 1, 2026) — California Building Standards Commission
  9. NEC Requirements for GFCIs and AFCIs — EC&M
  10. NEC Requirements for GFCI Protection: Section 210.8 — IAEI Magazine
  11. Fuse and Breaker Breakdown — Electrical Safety Foundation International (ESFI)
  12. Home Electrical Safety: A guide to understanding and maintaining your home's electrical system — Electrical Safety Foundation International (ESFI)
  13. Inspecting the Main Electrical Panelboard — InterNACHI
  14. 2024 AFCI and GFCI Performance Survey (California) — Electrical Safety Foundation International (ESFI)
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