Electrical Questions? Ask an Electrician Online.
Hi, I'm Mike and I'll be assisting you. Please stand by while I review your question.
Your description indicates the you lost one leg of the service. It could be the main breaker or a failed connection ahead of the main. You'll need a 2 wire voltage tester to pin point exactly where.
With the tester, put one probe on each termination where the service wire is connected. Then test each to the neutral bar. First reading should be 240V and the next 2 should be 120V each. Let me know the readings.