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.

Types of Surge Protectors

Some whole house surge protection devices connect to a circuit breaker while others are designed to connect directly onto the main terminals in your electrical panel 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.

There are also plug-in surge protection modules that are used to protect one electrical appliance or component.  Surge protection power strips allow several electrical items to be plugged in and protected.  It is important to read the labeling on these things.  You should only buy something that has a UL label or other testing laboratory approval.

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

Grounding Your Surge Protector

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 grounding 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 be 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.  The manufacturer required that the wires be twisted together.  It is important to follow the manufacturer’s instructions for proper operation of the surge protector and also to pass electrical inspection.

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, stereo amplifiers and receivers, 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.  Although the wire attached to the surge protector was only #12, the manufacturer required that it be connected to a dedicated 50 amp 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 electrical panel in a garage with a surge protector mounted on the left side.

A good post for you to read is how I grounded and bonded an older home due to the homeowners concern about lightning damage.

If you need to update your grounding electrode system you should read my post.