A power strip will trip if you have overloaded the power strip or if there's a fault in the wiring of the power strip or a fault in the wiring or appliance you have plugged into the power strip.
Things you should not plug into a power strip are high wattage appliances such as electric space heater, toaster oven, hot plate, electric kettle, sump pumps and washing machines are best not plugged into power strips.
However a hair dryer is generally safe to plug into a power strip as long as it's not on for longer than 5 minutes or so.
It is OK to use all the open plugs on an 8 outlet power strip as long as you don't overload the power strip by running to many amps through the power strip.
If you have small loads on the power strip or only use a few of the things plugged into the power strip at a time and they don't use more amps than the power strip is rated for then it's safe to use all the plugs on the power strip.
It's recommended that you replace power strips and surge protectors every 2 to 3 years.
However you can keep a power strip or surge protector as long as it's in good condition and the outlets are tight and not loose and you have no frayed wires on it.
Power strips can cause fires if the power strip is overloaded or if the power strip is bad.
If you overload the power strip then the power strip can start a fire.
Although if the power strip has a breaker on it then the breaker should trip when you pull too much power from the power strip.
Also never plug high wattage things into the power strip such as a space heater that runs longer than a few minutes or so.
Plugging a hair dryer into the power strip is generally safe as long as you don't run the hair dryer longer than 5 minutes or so at a time.
A space heater on the other hand would be a constant load which can heat up a power strip.
Space heaters should be plugged directly into an outlet.
If the power strip also has a frayed cord on it then it should be discarded and replaced.
A power strip gives you the ability to plug multiple devices into a single wall outlet.
A surge protector is a type of power strip which is specifically designed to withstand a power surge and keep your electronics safe.
As long as you don't overload the power strip or surge protector they should not cause any fire.
Also make sure the outlets are fitting tight and not loose and also make sure the outlet that you plug the power strip or surge protector into is tight fitting.
The loose connection of the outlet can cause the plug and outlet to heat up which can start a fire.