Zinsco Panel Replacement

How to Identify It

Zinsco (and GTE-Sylvania-Zinsco) panels are easy to spot once you know the look: slim breakers with brightly colored handles — teal, red, blue, green — lined up like crayons. Check the label for “Zinsco,” “Sylvania,” or “GTE-Sylvania.” They were installed heavily in the Valley through the 1960s and 70s, especially in Glendale, west Phoenix, and older Mesa.

• Label reads Zinsco, Sylvania-Zinsco, or GTE-Sylvania
• Colorful breaker handles (teal, red, blue, green)
• Slim vertical breakers on an exposed bus
• Home built 1955–1978 with its original panel

Why It Needs to Go

Zinsco’s fatal flaw is the connection between breaker and bus bar. The aluminum bus corrodes and the breakers’ grip on it loosens; the connection arcs, overheats, and in the classic failure, the breaker literally welds itself to the bus. Current keeps flowing even when the handle says off — which means the “dead” circuit you’re about to work on may not be dead at all.

Zinsco was never formally recalled — the company was sold and the design quietly discontinued — but the failure pattern is so consistent that inspectors, electricians, and insurers treat Zinsco as a replace-on-sight panel. In our own Valley work, it’s rare to open a 50-year-old Zinsco that doesn’t show bus pitting or heat discoloration somewhere.

Warning signs to act on now

• Breakers that won’t reset or feel loose in the panel
• Discoloration or bluish arcing marks on the bus
• A circuit that stays live with the breaker off
• Flickering that moves from room to room
• Insurance or inspection flag during a sale

REPLACEMENT COST

What Replacement Costs

FREE ESTIMATE — we come out, open the panel, inspect it, and give you a written flat-rate price. No diagnostic fee, no obligation, no pressure.