When I planned my own backyard wedding, I assumed we could just run a few heavy-duty orange extension cords out the kitchen window to power the reception. I had zero understanding of how much electricity a wedding actually requires.
A standard home outlet can handle about fifteen amps. A single commercial coffee percolator pulls almost nine amps. If your caterer plugs in a coffee maker, and the DJ plugs in his massive speakers, and you turn on two hundred feet of bistro lighting all on the same circuit, you will instantly blow a fuse. I know this because we blew the garage breaker three times during our dress rehearsal.
You cannot run a wedding of eighty people off your living room outlets. You have to rent a commercial, super-quiet inverter generator.
They are heavy, they smell like exhaust, and they cost a few hundred dollars to rent for the weekend. You also have to figure out where to put it so the guests do not have to listen to a motor humming during the toasts. We ended up hiding ours behind the neighbor’s detached garage and running a massive thick black cable across the lawn.
Do not wait until the caterer arrives to figure out your power situation. Rent the generator. It is the only way to guarantee the music does not suddenly stop when someone tries to brew decaf.