Surge Protectors

A permanently installed surge protector.
A permanently installed surge protector.

Dear Mr. Electrician: What is the best surge protector that will protect my computer from lightning if it should hit my house?

Answer: In the case of surge protection, bigger is better but not always necessary.  The ratings on various brands of surge protection device’s vary and can be confusing.  I think that it is best to do some homework before making a surge protection purchase.  Read reviews from other purchasers, compare the manufacturer ratings, check the price ranges for your budget.

Some whole house surge protection devices connect to a circuit breaker while others are designed to connect directly onto the main terminals without any circuit breaker protection or disconnect.  There are also surge protectors that plug directly onto the bus bar inside of an electrical panel in the same location that a circuit breaker plugs onto.  I prefer the type that can be disconnected, if necessary for replacement or servicing.

A Cutler Hammer surge protector mounted to an electrical panel
An Eaton surge protector mounted to an electrical panel.

Something else you should know, protecting your computer and other home electronics from lightning is not as simple as just installing a surge protector.  When a surge protector limits the high voltage from a lightning strike, it will need a means to dissipate the excess current.  In a well grounded home the surge protector’s lightning current would automatically be diverted to earth ground.  The same is true for a plug-in surge protector power strip.  The plug-in receptacle ground is connected to the grounding electrode system for the entire house and will only be as effective as the entire system.

The surge protector is connected to a dedicated circuit breaker as per the manufacturer's instructions. The manufacturer required that the wires be twisted together and that the surge protector gets connected to a 50 amp circuit breaker.
This surge protector is connected to a dedicated circuit breaker as per the manufacturer’s instructions.  The manufacturer required that the wires be twisted together and that the surge protector gets connected to a 50 amp circuit breaker.  The instructions also said to keep the wires as short and as direct to the circuit breaker as possible.  I was lucky to have an open breaker slot and a 1/2″ knockout in close proximity.

The home’s metal water service pipe, ground rods, well casing, and other metal pipes can be part of the grounding electrode system.  In an older home a weak link in the system due to a loose or non-existent connection or corrosion of a component may cause the surge protector to be ineffective or in some cases hazardous.

A closer shot of the surge protector connection to the main electrical panel.
A closer shot of the surge protector connection to the main electrical panel.

Before purchasing a surge protector you should examine the main grounding electrode (Usually a water pipe or a ground rod or both) and the grounding electrode conductor connected to your electrical service.  Lightning will usually follow the most direct path of least resistance to earth and you would prefer that it does not detour through any of your electronic equipment or appliances and cause damage.

Having an effective grounding system will not only enhance the electrical protection of your computer equipment, but all electronic devices such as TV’s, VCR’s, microwave ovens, satellite dishes, and virtually anything else that is electronically or microprocessor controlled.

Main panel labeled with the surge protector circuit breaker.
Main panel labeled with the surge protector circuit breaker.

Some suggested reading in the “National Electrical Code”:  Article 250 on Grounding, article 280 Surge Arrestors, article 285 Surge-Protective Devices.  Other books to read are Soares Book on Grounding and Bonding and NFPA 780 Standard for the Installation of Lighting Protection Systems.

Main panel with surge protector mounted to the side.
Main panel with surge protector mounted to the side.

You can read my post about your home’s grounding electrode system here