A surge protector diverts the excess voltage and current from transients or surges into the grounding wire and prevents it from flowing through the electrical and electronic equipment while at the same time allowing the normal voltage to continue along its path. This excess surge energy often causes damage in electrical and electronic equipment. Surge protectors are a must in todays electronics intensive homes and businesses. These devices work differently than lighting arrestors. What's the difference? one protects your home from inside and one protects the home from outside.
Should lighting strike your home, the lightning arrester, installed externally, would attempt to immediately detour the electricity away from your home and appliances and direct it instead to safe ground.
The surge arrester would perform a similar function, but it would instead intercept the surge caused by the strike and send excess energy into the grounding wire or another acceptable and predetermined grounding application. See the Lightning Protection tab of this section for exterior protection solutions.