breaker box trippin in house

[needa]

when i turn on the breaker outside at the ac unit, it immediately trips the breaker inside the house. it only happens when i have the thermostat turned on. nothing happens outside... the breaker just immediately trips. the unit is separate from the fan that blows throughout the house.

the wiring to the unit is in conduit and sits in the concrete for my breezeway. the unit is at least ten years old and the house itself if 18 yrs old.

i can fix anything, i just have to be told what to fix. i cant diagnose anything :(

we called out a repairman and the repairman says that we needed a new unit. this seems foreign to me.... why would i need a new unit if it is only tripping a breaker.

is it as simple as me replacing my breaker... please help.

[Lugnut]

The compressor in the outside unit is shorted to ground. This is not repairable. Need new outside unit.

[needa]

hmmm. bad news is not what i was hoping for ;)

[Lugnut]

Good news is that the old unit was probably under severe strain and costing you money. New unit will have higher SEER rating.

[hiltontech]

I'm with Lugnut, compressor seems to be dead, getting 18 years out of a unit is very good, she did you well, If I'm not mistaken 18 years for a compressor is like 81 in human years. :wall:

[DNT1]

If you really want to check the outside unit yourself and have some electrical skill lets verify first that something has not happened to the wiring to the unit. Turn the breaker off, go outside and verify that there is no power on the two lines L1 and L2 to the contactor now take both lines loose on the incoming side and and move them away from the contactor and apply two large wire nuts and electrical tape to isolate them where they are not touching anything. Not go back in and throw the breaker back on if it trips call your favorite electrician to start running a new feed line, if it holds turn it back off and go back outside remove the cover on the side of the compressor closely examine the wiring connections I have seen these burn off and lay against the housing shorts out and kicks a breaker every time. Take a couple of ohm readings to see if any of the feed wires are going to ground if so you have a bad compressor and can feel good about getting a new condensing unit.