[pscottn]

When my AS '79 trailer is plugged in for electrical power at a campground/park (shore line with direct connection), the air conditioner works on fan and cooling at all speeds with no problems.
However, if I plug the shore line with the proper 30 amp. adapter into a grounded extension cord and plug the extension cord in at home, the air conditioner will run fine on fan at all 3 speeds, but as soon as I turn the air conditioner to cool, it blows the circuit breaker in the trailer lavatory.
What causes this and is there anything I can do to rectify the problem? Does this mean it's time for a new air conditioner? Tell me "no", please!