Updated October 2026
Straight answer
Federal Pacific and Zinsco panel replacement in Boston means removing the whole panel, because new breakers do not fix a worn bus or a breaker design with a poor record of tripping. If the label inside your panel door says Federal Pacific, FPE, Stab-Lok, Zinsco or Sylvania, plan to replace it. We swap the panel, move every circuit, and test each one before inspection.
Why these panels get replaced, not repaired
A breaker has one job that matters: open the circuit when too much current flows. Independent testing of Federal Pacific Stab-Lok breakers found a high rate of breakers that failed to trip under overload, and Zinsco panels have a long record of breakers loosening on the bus and arcing. Neither problem shows up while everything is working normally, which is why these panels can run quietly for decades.
Home inspectors flag these brands on sight, and some insurers ask about them when you buy or renew. You do not need to panic if you have one, but you should not plan around keeping it. The fix is a full panel replacement, and it is often the right moment to look at service size if you are adding load.
The panel brands we replace most
Federal Pacific Stab-Lok panels
Federal Pacific panels went into many houses from the 1950s into the 1980s. You can usually spot one by the Stab-Lok name on the inner label and thin breakers that press straight onto the bus. The concern is the breakers, which in testing too often stayed closed under overload, and the way they grip the bus, which can loosen and overheat. Swapping in replacement Stab-Lok breakers keeps the same design, so we do not recommend it. We replace the enclosure, bus and breakers with a current panel, and check the service conductors and grounding while the power is off anyway.
Zinsco and Sylvania panels
Zinsco panels, and the Sylvania-branded versions that followed, are known for colorful breaker handles and an aluminum bus. The breakers clip onto that bus, and over time the connection can loosen, arc and in some cases weld the breaker to the bus so it cannot trip or be pulled out. When we open a Zinsco cover we often find pitting or discoloration on the bus stabs. Replacement breakers are scarce and do not cure a damaged bus. The answer is a new panel, and where the service conductors are aluminum we clean, treat and torque those terminations to spec on the new main.
Challenger and Pushmatic panels
Challenger panels from the 1980s have a record of certain breakers overheating at the bus, and one line of their ground fault breakers was recalled. Pushmatic panels, made by Bulldog, are older and often still work, but their push-button breakers stiffen with age, replacements are hard to find, and no AFCI or GFCI breakers are made to fit them. With either brand we inspect first. Sometimes the honest advice is replacement soon rather than today, and we tell you which it is and why, based on what the bus and breakers look like.
Read the label inside the panel door, then call us with the brand name.
Call (617) 843-6591What changes the price of replacing a problem panel
Replacing a problem panel is priced much like any panel swap, with a few details specific to these brands.
- Panel size. Matching the existing service is less work than moving to 200 amps at the same time.
- Bus and conductor damage. Heat at the old bus can mean trimming and extending circuits whose ends were cooked near the panel.
- Aluminum service conductors. Common with these panels, and they need cleaning, antioxidant and correct torque on the new main.
- Circuit protection rules. Circuits that are extended or modified pick up AFCI and GFCI requirements.
- Service equipment. An old meter socket or cracked service cable gets replaced in the same visit.
Replacing an old panel under current Massachusetts code
Boston houses collect panels the way they collect paint layers. A Federal Pacific or Zinsco box often went in when someone moved off fuses decades ago, and it has stayed through every kitchen and bath remodel since. Those later projects tend to add circuits by doubling up on breakers or adding tandems wherever they fit, so by the time we open the cover the panel is crowded and warm. Damp basements add rust on the enclosure and bus. Replacement is the moment to undo all of that: one conductor per breaker, a labeled directory, and room left for what comes next.
What comes with a problem panel replacement
- Inspection of the bus, breakers and wiring at the old panel
- New panel and all new breakers
- Every circuit moved, tested and labeled
- Cleaning and torque on aluminum service terminations
- Heat-damaged wire ends cut back to sound conductor
- Grounding and bonding checked at the service
- Permit filed and inspection scheduled
- Old panel taken out of the house
How a problem panel comes out
Identify and inspect
We confirm the brand, open the cover and look for heat damage on the bus and wire ends.
Plan the size
Same service size or an upgrade, based on what you run now and plan to add.
Permit and shutdown
We file the permit and arrange the power shutdown for the work day.
Replace and reland
New panel and breakers in, every circuit moved, tested and labeled.
Inspection
The wire inspector reviews the work before the job is closed out.
Signs your old panel is failing
Breakers that feel warm
Heat at the breaker face points to a poor connection at the bus or terminal.
Breakers that sit crooked in the row
A loose grip on the bus, common in worn Stab-Lok and Zinsco panels.
A breaker that will not switch off
A stuck handle can mean the breaker has welded itself to the bus.
Scorch marks or a burnt smell at the panel
Arcing has already happened; call before resetting anything.
The label says FPE, Stab-Lok or Zinsco
The brand alone is reason enough to plan a replacement.
Federal Pacific and Zinsco questions
The risk is that a breaker does not trip during an overload or short, so the wire heats up instead. Many FPE panels run for years without trouble, but the failure stays invisible until it matters, which is why we recommend replacement.
Not usefully. Replacement Stab-Lok and Zinsco breakers use the same design, and they do nothing for a bus that has already loosened or pitted. A new panel fixes both problems at once.
Open the panel door, not the cover, and read the label on the inside. Federal Pacific, FPE, Stab-Lok, Zinsco, Sylvania, Challenger and Bulldog Pushmatic are the names to look for. Read us the name when you call.
It is not usually an emergency unless there is heat damage, a burning smell or a breaker that will not reset. Plan the replacement soon, and call right away if you notice any of those.
Some insurers ask about panel brands when you buy or renew a policy. After the replacement, we give you a written description of the new panel and the work done for your records.
If a heat pump, EV charger or electric range is in your plans, it is often the right time. If not, a same-size replacement is less work and fully solves the safety issue.