Surge protection & GFCIs

Ground fault circuit interrupters

A ground fault circuit interrupter (GFCI) is a type of outlet that should be installed where appliances or power tools may come in contact with water, such as laundry rooms and garages. While GFCIs are required by code in new kitchens, bathrooms, unfinished basements, and outdoor receptacles, they can be retrofitted into older homes.

GFCIs monitor the amount of electricity flowing through a circuit. It will shut off the circuit if it detects current flowing along an unintended path, such as through your body or water, which can prevent serious electric shock or fire.

Temporary or portable GFCIs can be used for construction or outdoor projects, but they should be tested before each use. They should not be used as a permanent alternative to a regular GFCI.

GFCIs should be tested monthly, as lightning and other power surges can damage a GFCI's delicate circuitry. To test your GFCI:

  1. Plug in a light fixture and turn it on.
  2. Push the Test button on the outlet plate. The light should turn off. If the light stays on, the GFCI needs to be replaced.
  3. If the light turns off, press the Reset button. The light should turn back on.

Surge suppressors

Photo of a main panel surge suppressor.

The surge suppressor at your main service panel deals with large surges.

Surge suppressors protect electrical devices from power surges by limiting the amount of electricity reaching your connected devices. They are not designed to offer protection from a direct lightning strike, which can pack up to 100,000 volts.

Power surges are usually caused by a brief voltage fluctuation. It typically ranges from 500 to 1,000 volts and hits a component designed to withstand only 120 volts. This can damage electronic devices like your computer, home entertainment system, telephone, appliances and security system. In the case of your computer, a power fluctuation can disrupt software, erase valuable data and damage the hard drive, printer, modem and other related equipment. As a precaution, unplug your computer when you are not going to be using it for an extended period.

For the best protection for your equipment, use a combination of a main service surge suppressor and several point-of-use surge suppressors.

Main service surge suppressors:

  • Main service surge suppressors protect your home from power surges originating from the utility supply. They cut big surges down to size, enough so that if any of the surge is left, your point-of-use surge suppressor can intercept it to protect your equipment.
  • Local electrical suppliers carry a full range of surge suppressors for every degree of surge protection needed in your home or business. Have a licensed electrician install the main service panel suppressors in your home.
  • Look for a response time of 5 nanoseconds or less, and a visible alarm to signal that the device has suffered damage, since surges can destroy the suppressor's effectiveness.
  • Good quality building-entry surge suppressors cost between $200 and $700.

Point-of-use surge suppressors:

Photo of different types of smaller point-of-use surge suppressors.

Smaller point-of-use surge suppressors take care of the remains of surges.

  • Point-of-use surge suppressors are connected to wall outlets close to equipment being protected. They generally take the form of power bars, receptacle-mounted or plug-in types, and hard-wired receptacles with built-in suppression. Look for certified CSA or cUL and UL 1449 approval.
  • Point-of-use devices are available at computer retail outlets, hardware stores, and department stores.
  • The suppressor should be able to handle a minimum of 120 joules without burning out, across each of the following: neutral to ground, neutral to line, and line to ground. Look for suppressor power bars with audible/visible alarms to signal when the device has suffered damage, since surges can destroy the suppressor's effectiveness.
  • Good quality surge suppressor power bars generally range from $30 to $75.

Here are some things to keep in mind when purchasing a surge suppressor.

  • Most manufacturers guarantee that the surge suppressor will protect your equipment up to the dollar amount specified, which could be anywhere from $500 to $25,000. The higher the dollar amount specified, the better.
  • The maximum voltage that the suppressor will let through to protected equipment. The lower the voltage, the better.
  • Response time is how long it takes for the suppressor to respond when it detects a power surge. Look for a response time in nanoseconds (one-billionth of a second) or picoseconds (one-trillionth of a second). The lower the number, the faster the response, the better the protection.

For more information, contact your local Manitoba Hydro office.


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