Can a burglar disable a home's security system by cutting all the wires and power?

[kimsanders]

If a burglar cut all power source to the house, can the alarm be disable ? And, if he cuts the phone line too, the alarm wont be able to call the police even tho it might be running on a battery due to the power cut. So an alarm isn't that effective in the end, right ?

[sophie hello]

I‘m not sure, but I will google it.

[Berry lee]

All alarm systems have a back up battery and will last several hours without electricity.

[Kaslandy]

What if the burglar cut off the wires that connects the security devices?