Just today I have heard a loud buzzing noise in the house. I have lived here 16 years and never heard it before. It is loud, lasts a few seconds and sounds electrical. I cannot isolate where it is from. I looked to see if the breaker box had any tripped breakers, no. I also have the furnace running, sounds normal. Does the electrical box make a noise if something is going bad? I shut everything down and turned off the main switch. Then re-started everything. About 20 minutes later, I heard the noise again. It is from somewhere in the basement....Circuit Breaker? Water Heater? Furnace? Any ideas?