Why do I need Surge Protection Devices (SPD's)?

Jeff Cox, Power Plus Electrical Service, Inc.

  • Why do I need a SPD's?

We need SPD’s to help extend the life of electronics and appliance in our homes, by discharging the surge to ground instead of the surge being absorbed by your electronic device and damaging the device or destroying the device.

Some electronic devices and appliances that we take for granted are, LED light bulbs, refrigerators, ranges, dishwashers, clothes dryers, washing machines, furnace, air conditioners, garage door openers, routers, GFCI receptacles and breakers, AFCI breakers...

One thing all these components have in common is that they are affected by power surges.

Power surges shorten the life of these components and can destroy them if the surge is large.

You probably already have surge protector strips in your home to protect your computer and TV. But what about larger appliances? These appliances need to be protected with Type 3 receptacles in conjunction with hardwired Type 2 and Type 3.

  • What is a Surge Protector?

A surge protector is a device that will protect your electrical equipment from a sudden burst of energy by discharging the energy to ground.

  • Where Do Surges Come From?

For a better understanding, you need to know that:

  • A minor amount (approximately 20%) of surges originate outside the home from nearby lightning strikes, which produce surges into nearby power wires.
  • Normal utility operations can cause electrical disturbances.
  • The most common external surge source is when power is interrupted for any reason – a tree falling on wires, a car hitting a pole, wind damage, utility repairs, etc. Wires conducting electricity create a magnetic field. When power is interrupted, the magnetic field collapses, inducing large voltages in the wires.
  • The majority of surges (approximately 80%) come from within the home and are generated every time equipment cycles on and off. This is the same principle as the above item. When an appliance such as your washing machine cycles off and on it produces small surges that are induced in the homes electrical system. The further the appliance is from the breaker box the larger the surge.


  • Types of Surge Protection

Effective surge protection occurs with a layered approach for maximum protection.
The first layer is Type 1.

  • Type 1

Tesco Meter Socket Device.

These devices are installed at the homes metering equipment. These are the first line of defense for protection from 20% of surges coming from outside the home, such as lightning, spikes from the power company, and surges from damaged power lines.

The second layer is Type 2.

  • Type 2


A Type 2 whole house surge protector is installed on the main branch circuit panel or panels. Type 2’s are installed on the load side of the main service entrance and primarily provide protection from 80% of internally generated power surges.

The third layer is Type 3.

  • Type 3

This category provides point of use surge protection and are most commonly known as power strips.  They discharge the lower level voltage spikes that can be damaging to more sensitive electronics like your computer, audio component, televisions and other household appliances. Surge protection receptacles are an effective way to protect appliances such as refrigerators, washing machines… appliances that cannot accommodate a power strip.