A surge protector functions like a power strip but it also serves another very important function. A surge protector will also protect your electronic devices from a power spike. A power spike is a very high increase in power that lasts for a fraction of a second. It can be caused by lightning strikes or power outages, tripped circuit breakers or short circuits. In order to tell the difference between a power strip and a surge protector, you have to look for an electric rating. A surge protector will have a rating in Joules of energy, as well as the maximum voltage it can take from a power spike.