Half your outlets are dead and the breaker looks fine

The confusing part of this problem is the thing that did not happen. You went to the panel expecting to find a breaker sitting halfway, and every one of them is sitting exactly where it should be. So the natural conclusion is that the panel is fine and something stranger is going on.

The panel probably is fine. A breaker is only one of several things that can open a circuit, and it is the only one that announces itself. A GFCI can cut power to outlets three rooms away without moving a breaker. A single loose connection inside a receptacle can kill everything wired after it while the breaker stays closed, because from the breaker's point of view nothing is wrong: no overload, no fault, just less current than before.

What a quiet breaker does tell you is real and worth keeping. It rules out an overload on that circuit. Whatever is happening, you are not asking for more power than the wire can carry, which takes the most common cause of electrical trouble off the table and points the search somewhere more specific.

This is the part worth slowing down for. People describe this problem by what stopped working, and the far more useful measurement is how much stopped working and whether the dead outlets sit together.

A handful of outlets clustered in wet-area rooms points upstream to a GFCI. A full run going dead in order points at a failed connection partway along the chain. Roughly half the house going dark while the other half behaves perfectly points at something else entirely: a lost leg at the service, which is not a circuit problem at all. Work the check below, or read the same logic in the table under it.

All four of these stay on the safe side of the line. Nothing here asks you to open a device or remove the cover from the panel.

1. 1

   Map what is actually dead before you touch anything

   Walk the house with a phone charger or a small lamp and test every outlet, room by room, including the garage and any outdoor boxes. Write down what works and what does not. The shape of that map is most of the diagnosis, and it is the first thing our team asks about on the phone.

2. 2

   Check the lights separately from the outlets

   In most homes the ceiling lights and the wall receptacles are on different circuits. Lights that still work in a room with dead outlets is normal and useful: it tells you the house has power and the problem is confined to one circuit rather than the service.

3. 3

   Find every GFCI, not just the obvious ones

   Look in the garage, the laundry area, outdoors behind weatherproof covers, in crawlspaces and basements, and in every bathroom. One bathroom GFCI commonly protects a second bathroom that has no button of its own. Press the reset button firmly on each one and listen for the click.

4. 4

   Reset the suspect breaker fully, off then on

   A breaker that has tripped often rests in a middle position that looks close enough to ON to fool anyone. Push it firmly all the way to OFF first, then back to ON. If it will not latch, or it snaps straight back off, stop there and read the guide on breakers that keep tripping.

This is the single most common answer to dead outlets with a live breaker, and it is the one homeowners solve themselves most often once they know where to look.

A GFCI does not just protect the outlet it is built into. Wired the usual way, it also protects every receptacle downstream of it on that circuit, and those downstream outlets have no buttons of their own. There is nothing on their faces to suggest they are being controlled from somewhere else. So when the GFCI trips, four or five ordinary-looking outlets across two or three rooms go dead at once, and the device responsible can be somewhere you would never think to check.

The places it actually turns up, roughly in order:

• The garage, often behind a workbench, a shelf, or a parked car, and frequently the culprit for dead kitchen or exterior outlets
• An outdoor receptacle under a weatherproof cover, which is also the one most likely to trip after heavy rain
• The laundry area, sometimes behind the washer or dryer
• A crawlspace, basement, or utility closet
• A different bathroom from the one with the problem, since one bathroom GFCI commonly protects a second
• The panel itself, if the home has GFCI breakers rather than GFCI outlets. In that case the reset is a small button on the breaker

Press reset firmly on each one and listen for the click. If a GFCI resets and then immediately trips again, that is a different problem with its own answer, and the guide on GFCI outlets that will not reset covers it.

If every GFCI in the house is reset and a run of outlets is still dead, the circuit itself has been interrupted somewhere along its length.

Outlets are wired in a chain. Power arrives at the first one, passes through it, and carries on to the next, and so on to the end of the run. That means any single failed connection takes out that outlet and everything after it, while everything before it works normally. The pattern on your map, one section of a room dead and the rest fine, is that chain broken at a specific point.

The usual failure point is a push-in connection on the back of a receptacle, where the wire is held by a small internal spring rather than clamped under a screw. Those contacts relax over decades of heating and cooling, and Santa Clara County has an enormous number of homes old enough for that to have happened. Loose wire nuts in a junction box and corroded terminals are the other common versions.

In homes wired between roughly 1965 and 1973 there is a further wrinkle worth knowing about. Aluminum branch wiring was widely used in that window, and aluminum expands and contracts more than copper does, so its connections loosen faster and run hotter when they do. Dead outlets in a house of that age deserve a closer look at the connections themselves rather than a single repair and a shrug.

Finding the break means opening devices in order and testing the run, which is where a homeowner should stop and our team should start.

If your map came back showing something close to half the house dead and the other half completely normal, this section is the one that applies, and it is a different category of problem from everything above.

Your home is fed by two 120-volt legs. Combined they give you the 240 volts that runs a dryer, a range, an AC condenser, or a car charger, and individually they each carry about half of your 120-volt circuits. When one of those legs is lost, every circuit sitting on it goes dead simultaneously, and every circuit on the other leg carries on as though nothing happened.

That is why the outage looks so arbitrary from inside the house. The dead rooms are not next to each other and have nothing obvious in common, because what they share is not location, it is which leg they were assigned in the panel.

The cause is usually one of three things: half of the main breaker has failed, a connection in the panel has loosened, or there is a fault on the utility side of the meter. Telling those apart takes a meter inside an energized panel, which is not homeowner work under any circumstances.