Fault-finding
The AC trips the breaker
Usually not the compressor. A failed capacitor, a shorted fan motor, moisture in the outdoor unit after rain, or an undersized supply cable that has been marginal since installation account for most of them — and all four are far cheaper than the compressor everyone fears.
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Note when it trips, because that names the cause
Tripping at the moment of start-up points at start-up current — a failed capacitor, a stiff compressor, or a supply cable too thin for the inrush. Tripping after a period of running points at heat, a motor drawing progressively more, or a marginal breaker. That single observation narrows the diagnosis before anyone opens a panel.
Test the capacitor first
Capacitors fail more than any other component in this climate, and a failed one leaves the compressor or fan motor drawing far above its rating until something trips. It is inexpensive, quick to test with a meter, and quick to replace. Assuming a dead compressor before testing the capacitor is how a small repair becomes a quotation for a new unit.
Check for moisture and rodents in the outdoor unit
Outdoor units sit exposed, and after heavy rain water finds its way into a terminal box with a perished seal. Rodent damage to cabling is also more common than people expect. Both produce intermittent tripping that looks mysterious until someone actually opens the outdoor casing and looks.
Then question the supply itself
An AC on an undersized cable or sharing a circuit with other heavy loads sits close to the breaker's limit permanently, and trips on a hot day when everything runs at once. That is a wiring fault rather than an AC fault, and no amount of work on the unit will fix it. It also needs fixing for safety, not just convenience.
Why does my AC trip the circuit breaker?
Can I just replace the breaker with a bigger one?
No — and this is the most dangerous shortcut in this list. The breaker is sized to protect the cable, so fitting a larger one means the cable can now overheat without anything intervening. If the breaker is genuinely undersized, the cable has to be assessed and usually upgraded with it.
It trips only in the afternoon. Why?
Because everything is working hardest then: ambient temperature is highest, the compressor draws more, and other loads in the house are also running. A system sitting marginally within its limits at nine in the morning is over them at three. That pattern usually points at a weak capacitor or a supply that was never quite adequate.
How do I know if it really is the compressor?
By measurement — insulation resistance and winding continuity, after the capacitor and the supply have been ruled out. A genuine compressor failure is uncommon relative to how often it is diagnosed. Ask what was measured and what the readings were; a diagnosis with no numbers behind it is a guess.
Rather have it done?
AC repair covers units that will not start, trip the breaker, run without cooling, leak water into the room or make a new noise. Callout and diagnosis in Islamabad or Rawalpindi is PKR 2,500, taken off the bill if you proceed, and the repair is priced before any part is fitted.
AC repair and spare parts in Islamabad — prices and scope