Thank you for your inquiry.
Is this a 120 volt window unit, or a 240 volt
window unit?
If this is a 240 volt window unit, chances are that
it would have an individual circuit. And if that is
the case, why would it not trip the individual circuit
first, before tripping the main breaker?
If this is a 120 volt window unit, other appliances
could be on the same circuit. And this brings us back
to the same question, why would it not trip the individual
circuit first, before tripping the main breaker?
With so little information, it would be next to impossible
for the electrician or the HVAC man to give you any
useful information.
On the electrical side
Please do not take this as advice, this is simply someone's
opinion.
One of our electrical contributors suggested that this
could be a defective main circuit breaker. He works
with apartment complexes, and they have a big problem
with their main breakers failing where the breaker contacts
the bus bars in the main panel. Sometimes they can get
by with just replacing the main breaker, and other time,
when the bus bars are badly burned, they must replace
one of both of the bus bars in the main panel. At any
rate, if this was the cause, this is definitely a job
for a licensed electrician.
On the HVAC side
Please do not take this as advice, this is simply someone's
opinion.
One of our HVAC contributors have suggested that a dirty
condenser coil, could raise the head pressure, and cause
it to pull a higher amperage. However, he could not
see how even that would cause your main breaker to trip.
Both the electrician and the HVAC men both agree, that
you should contact one of your local contractors, and
have them diagnose the problem.
