A340. From left to right top to bottom.
Silver bat switch: 1, 2, apu. Selects what bat voltage is displayed in lcd next to it.
Bat 1, Bat 2, APU Bat push buttons: Turns bats on or off.
Galley: Turns off power to galleys.
Commercial: Turns off power to almost everything in the back, including galleys.
AC ESS FEED: Switches feed of AC ESS BUS from AC BUS 1-1 to AC BUSS 2-4
Bus Tie: In is auto, computers auto configure contactors in case of failures or switching power sources. Out opens all contactors so each bus is isolated. Used to find out what may be causing smoke.
IDG 1, 2, 3, 4: Used to disconnect the gen from the engine. Physically disconnects its drive.
Gen 1, 2, 3, 4, APU GEN push buttons. Turns off a generator. Or turns one on if you had turned it off. Normally left in all the time.
Ext A/B push buttons: When ext power is avail can push button to connect it to aircraft buses.
This is how the panel would look like with all engines running on ground or in flight with no failures.