The afternoon storm passed over the Castillo and now the AC breaker won't hold: the one-reset rule

One reset, then stop

A breaker trips because something downstream drew more current than the wire is rated for, or because a surge came through. Reset it once. If the system starts and runs normally, note the day and move on; a single trip after a nearby strike is common and often harmless. If it trips again within minutes or hours, leave it off and call. The second trip means a real fault, and each additional reset sends full current into a compressor or a wire that is already in trouble. We have seen a repairable capacitor problem turned into a failed compressor by an afternoon of resetting.

Why breakers trip more in this town

Four reasons, and most St. Augustine houses have at least two.

Lightning. The summer storm pattern builds inland and rolls east over the city most afternoons from June into September. A strike anywhere near the FPL lines sends a surge into every house on the circuit, and the outdoor unit, with its big motor and its control board, is the most sensitive load in the house.

Salt. East of the Intracoastal, at Vilano, St. Augustine Beach and Crescent Beach, and along the bayfront, salt air corrodes the contactor, the terminals and the wire ends inside the outdoor unit. Corroded connections arc and heat; arcing draws current; the breaker trips.

Age. The compressors installed across World Golf Village and Murabella in 2004 to 2008 are now drawing more starting current than they did new. A tired compressor on a 93-degree afternoon is the classic second-trip scenario.

Old wiring. The historic core, Lincolnville, the Abbott Tract and the Model Land District have houses whose electrical systems predate central air by decades. Undersized circuits, panels at capacity and aluminum branch wiring from mid-century additions all show up as nuisance trips that are not nuisances.

Breaker, disconnect or float switch: which one tripped?

Three different things can stop a system and get called a “trip.” The breaker is in the panel, usually a double-pole for the outdoor unit and another for the air handler; a tripped one sits between On and Off. The disconnect is the small box on the wall near the outdoor unit; it has a pull-out or a switch and sometimes its own fuses, which blow rather than trip. The float switch is on the drain line at the air handler; when it opens, the system stops as if the power were cut, but nothing in the panel moves. Check all three before you call, and tell us which one you found. A float switch is a drain problem; a blown fuse at the disconnect is often a shorted compressor; a tripped breaker could be either side.

Tell us what you found

What we test, in order

The breaker itself, for correct size and signs of heat. The wire from panel to disconnect and disconnect to unit, for loose or corroded terminations. The contactor and capacitors, which fail from heat and salt long before anything else. The compressor and fan motor windings, for shorts to ground and for starting current against the nameplate. The control board, for surge damage. Then the air handler circuit: the blower motor and the heat strips, which trip their own breaker when a sequencer sticks or an element shorts. Every step gets a reading, and the reading decides the fix. You get the price before the part.

When the panel is the problem and not the air conditioner

Sometimes the system tests clean and the breaker still trips. A breaker that has tripped many times weakens and trips below its rating. A panel with a loose bus connection heats the breaker from behind. A circuit shared with something else, a garage freezer, a well pump in Flagler Estates, overloads under both. Those are electrician work, and we say so, and we coordinate rather than installing a part that will not fix it. On an older downtown house, that conversation often starts with the first repair visit and ends with a panel upgrade before the next system goes in.