A surge protector prevents a spike I'm the power from reaching your thermostat on your rack and the thermostat in the Reptibator incubator. The surge protector doesn't do anything if a thermostat itself fails. When thermostats fail, usually the mechanism the turns down the power supplied to the heating element opens up all the way and the heating element gets full power and the temperature spikes. This can kill or deform embryos developing in the egg and burn adults. This is why I have a 6 outlet surge protector that is connected to my household outlet. For each rack, I have a VE-100 thermostat plugged into the surge protector. The VE-100 is set to 95 degrees. Plugged into the VE-100 is a VE-300 thermostat set to 90 degrees. Plugged into the VE-300 is a power strip and different levels of my rack are plugged into different outlets on the power strip (this way I can unplug a level if a tub is empty). This setup requires 2 thermostats to fail simultaneously before my racks overheat. I use the same setup for my incubator in a different room.