A home-alarm system shares the electric power that runs through the house in much the same was as the refrigerator or air conditioner/heater unit does. The fuse that controls the flow of electricity to the home-alarm system's control panel is found in the home's fuse box. You can check which of the fuses that connects electricity to the home-alarm system to know what type to buy as a backup and which to access in case of a problem. The procedure is straightforward and will not harm the home-alarm system in any way.
Have an assistant stand at the fuse box. Typically, this is in the basement of the home, although in some cases it can be found in an attached garage or in a utility closet. Go to the home-alarm system's control panel. Enter the password on the keypad to disarm the system. Leave the menu setting that now appears on the control panel's LCD screen alone.
Call your assistant on your cell phone. Tell him to pull a fuse in the fuse box. Look at the control panel's LCD screen to see if "Battery Backup," "Warning/Electric power Disconnected" or similarly worded text appears on the LCD screen. If the text does not appear, tell your assistant to return the fuse to its original position and remove the next fuse. Continue to do this until the text signifying that the electric power has been discontinued to the control panel appears. Tell your assistant that the fuse just pulled is the one supplying the control panel with electrical power.
Have your assistant place the fuse back in its socket in the fuse box. Navigate to the "Reset" menu on the control panel. Activate the "Reset" setting. Enter the password to arm the system and allow it to reset itself.
Write "Control Panel" on a sticker and apply the sticker to beneath the fuse that controls the electrical power that goes to the control panel.
A fuse puller from a hardware store will make pulling the fuse easier to do.
If the home-alarm system is part of a subscription service that includes an off-site monitoring station, call the station and let them know that you are shutting off power to the alarm first.