Spring is here and I’ve been researching whole house electrical surge protection solutions to safeguard the appliances, air conditioner and other expensive electronics to prepare for the thunderstorm season. Choosing a surge protection solution can be confusing because of the wide variety of surge suppression products on the market.
Electrical Surge Protective Device Requirements
Surge protective device (SPD) requirements are defined in Underwriters Laboratories specification UL 1449 3rd Edition 2009 which defines four device designations:
- Type 1 – Permanently installed between the electric company transformer and the line side of the service equipment, or installed on the load side, including electric meter socket devices and intended to be installed without an external overcurrent device. Aside: A circuit breaker is an example of an overcurrent device (OCD).
- Type 2 – Permanently installed on the load side of the service equipment OCD, including SPDs at the circuit breaker panel.
- Type 3 – Point of use SPDs installed at least 30 feet of wire length from the circuit breaker panel. Examples are plug-in modules and corded connected (e.g. powerstrips) SPDs.
- Type 4 – Component SPDs – discreet electronic parts and assemblies that make up a SPD.
Type 1, 2 and 3 SPDs are the main interest for homeowner’s.
Residential surge suppression devices are commonly installed in these locations:
- Electric meter – Type 1 SPD to stop surges before it can enter the home.
- Circuit breaker panel – Type 1 or Type 2 SPD wired into the service panel.
- Plug-in power strips – Type 3 SPD which protects only the appliance and household electronics (HDTV, DVR, computer) plugged into the strip.
This diagram summarizes electrical surge protection devices for the home:
Type 1 and Type 2 Surge Protective Devices (SPDs) should be installed by your electric company or a licensed electrician. As shown in the diagram, I’m using a Type 1 Meter-Treater 400-1SL SPD and several Type 3 Panamax M8-AV SPDs in my home.
I did not install a SPD at the circuit breaker panel (see the purple square in the above diagram), instead relying on the Meter-Treater at the electric meter for whole-house surge protection.
Layered Electrical Surge Protection
The best surge protection strategy is a layered defense employing several SPDs at different locations in the home because no single device can protect everything. A SPD should be installed at the service entrance (electric meter) to stop surges before it can enter the house with additional point-of-use surge suppressors (plug-in strips) and surge devices for your telephone/DSL line and cable TV. Plug-in strips are available at most any home electronics or improvement store and very simple to use.
Electrical Surge versus Over Voltage Conditions
An electrical surge or spike is a transient high voltage event that typically lasts a fraction of second. Surges can be caused by many things including lighting, or a squirrel or tree short-circuiting the power lines. The surge protection device (SPD) must have a very fast reaction time to safely direct the surge to ground before it can damage household appliances and electronics. The SPD may sacrifice itself and have to be replaced.
Over voltage conditions are different from spikes and surges in that a persistent high voltage enters the house wiring due to a fault in the electric company’s power distribution system. For example, a fire ant nest bridged the coils in the electric company’s transformer creating a pathway for high voltage to enter the home causing severe damage. This over voltage condition probably lasted for hours.
Surge protection devices generally do not protect against over voltage conditions.
The NIST Surges Happens! How To Protect The Appliances in Your Home is a comprehensive overview of electrical surges and protection strategies.
Electric Meter Whole House Surge Protection
My challenge was finding the right service entrance surge suppression solution because it requires professional installation and/or permission from the power company. I was pleased to learn my electric company offered the Meter-Treater whole house surge protector for a monthly charge of only $5.50. Many power companies offer a premium surge protection service, so call your electrical utility to find out.
The electric company installed a Meter-Treater, Inc. 400-1SL which is certified as a Type 1 SPD per UL 1449 3rd Edition. What I really liked is the warranty to repair or replace damaged motor-driven appliances. Note that the warranty doesn’t cover sensitive electronic items, meaning TVs, computers, stereos, telephones, etc.
This is my electric meter before Meter-Treater:
Power was interrupted for a few minutes while the electric company installed the Meter-Treater 400-1SL surge protector. The unit installs on the base of the watt-hour meter as shown:
The Meter-Treater has a two very bright status LEDs that are visible in direct sunlight. Both LEDs must be on to indicate the unit is functioning properly.
By the way, my electric meter box has a 150 Amp Service Disconnect switch which will shutoff power to the home. This switch is useful if the main service panel (circuit breaker panel) inside the home needs replacement or upgrades.
This project is continued in Whole House Electrical Surge Protection – Part 2.