Older wiring
Home Rewiring for Older Walnut Creek Homes
Homes built or rewired between 1965 and the mid-1970s may have aluminum branch wiring, which CPSC links to overheating at connections. CPSC recognizes three permanent fixes: copper rewiring, COPALUM crimp connectors or AlumiConn connectors.
Aluminum branch wiring
The timing matches the local housing stock: Walnut Creek's median home was built in 1974, Pleasant Hill's in 1972 and Concord's in 1970 (Census).
CPSC says cable installed between 1965 and the mid-1970s, in new homes, additions and rewired circuits, may contain aluminum. The hazard it investigated is at the connections: outlets, switches and junction boxes, where aluminum can overheat when current flows.
An electrician can confirm it; the cable sheathing in an attic, basement or garage is often printed with "AL" or "ALUMINUM."
Repairs CPSC recognizes
| Method | What it is | CPSC view |
|---|---|---|
| Copper rewiring | Replacing aluminum branch circuits with copper cable | Permanent |
| COPALUM connectors | Copper pigtails joined with a special crimp tool | Permanent |
| AlumiConn connectors | Set-screw lug connectors for pigtailing | Permanent alternative |
| Twist-on connectors | Standard wire nuts used as pigtails | Not a permanent repair; overheated in CPSC testing |
Ungrounded and overloaded circuits
- Two-prong outlets: no equipment ground. Options are a new grounded circuit, or GFCI protection marked "No Equipment Ground" under NEC 406.4(D).
- Too few circuits: kitchens, home offices and bathrooms sharing one circuit trip breakers. New circuits may also need panel space.
- Old cloth-covered cable or brittle insulation: have an electrician evaluate it rather than disturbing it.
Partial or whole-home rewire
| Scope | Disruption | Makes sense when |
|---|---|---|
| Connection repair (COPALUM, AlumiConn) | Low: work at each device | Aluminum wiring is the main issue |
| Partial rewire | Moderate: some wall openings | One area (kitchen, addition) is the problem |
| Whole-home rewire | High: many openings, patching, paint | Remodeling anyway, or several problems at once |
Rewiring is quoted per job; there's no reliable local average. Ask whether patching and paint are included. Cost guide.
Often paired with a panel replacement
Homes from this era may also have a Federal Pacific or Zinsco panel. Doing the panel and wiring together means one permit cycle and one set of wall repairs. See old panel replacement and panel upgrades.
Rewiring questions
Is aluminum branch wiring dangerous?
CPSC investigated it and found that connections with aluminum wire, at outlets, switches and junction boxes, can overheat, sometimes to hazardous levels. Not every aluminum-wired home has a problem, but CPSC recommends permanent repair methods rather than leaving it as is.
Do I have to rewire the whole house?
No. CPSC recognizes repairing the connections with COPALUM crimp connectors or AlumiConn connectors as alternatives to full copper replacement. An electrician can tell you which fits your home and budget.
Can I just add grounded three-prong outlets?
Only with a real equipment ground, or under the code's exception that allows replacing an ungrounded outlet with GFCI protection and marking it "No Equipment Ground" (NEC 406.4(D)). Surge protectors and some electronics still want a true ground.
Does rewiring need a permit?
Yes. Rewiring is permitted electrical work. Walnut Creek accepts permit applications only through its online portal; other cities and the County have their own.
Sources
Next step
Talk to an electrician about older wiring
Call to talk it through, or send the short form. A local electrician can follow up to look at your panel and service and give you a written quote.
Call (925) 722-6103Prefer to type? Use the form.