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Energy & Safety

Power Disturbances
 

Disturbances that affect power quality are bound to occur. Some may only briefly interfere with the most highly sensitive equipment. Others, due to extensive damage on our electric delivery system, could result in the total loss of power for days.

If you're a homeowner, you can take steps to minimize the effects of these disturbances. For companies that depend on digital-quality power in their business processes, more specialized power system solutions may be needed.

Types of Disturbance Possible Effects Common Causes What You Can Do
Sag      
A short duration drop in voltage. Most appliances will continue to operate normally, but lights may dim briefly and television pictures may, for a moment, shrink slightly. More sensitive equipment could be more noticeably affected. Start-up of large appliances or motors; faults on the electric delivery system caused by accidental damage, animal contact or tree interference. Connect computers and other sensitive electronic devices to circuits other than the ones your large motor-driven appliances are on; try to lighten the load on the affected circuit.
Surge      
A short-duration increase or spike in voltage lasting as little as a few millionths of a second and varying from a few hundred volts to several thousand volts.

 

 Damage to VCRs, televisions, computers and electronically controlled appliances. Susceptible appliances can usually be identified if they have electronic push buttons, electronic clocks, or digital displays. Lightning surges that come into your building by way of the wires — power, telephone, cable TV or other; switching surges that occur when electrical loads are turned on or off either in your home (large motor-driven appliances) or on the electric system grid. At a minimum, install point-of-use surge protectors with a 330-volt clamping voltage for all expensive electronics and appliances, such as TVs, VCRs, stereos, and computers. Be sure other wires from telephone system, cable TV, roof antenna, or satellite dish, are protected as well.
Noise      
A continuous distortion of normal voltage. Snow on television screens or constant static on radios. Most common cause is the operation of small appliance motors, such as blenders, electric shavers or power saws. Identify appliances causing the noise.
Momentary Interruption      
Occurs when power is briefly cut off, lasting from a fraction of a second to as long as a minute.

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 Brief loss of power causing digital clocks to blink, electronic devices to reset, computers to lose data. Animal or tree contact with a power line; accidents involving our power line poles. To prevent loss of data while working on a computer, install an uninterruptible power supply (UPS). When purchasing electronics with digital time displays, look for devices with a battery backup.
Power Outage      
An outage is registered whenever the electricity is completely interrupted for a minute or longer.

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 Total loss of power to computers, cordless phones, refrigerators, well pumps, sump pumps, medical devices and other electrical appliances. An unplanned outage due to storm or accidental damage to our power lines and equipment; a planned outage due to scheduled maintenance of our system. Occasional unplanned power outages are unavoidable; being prepared for them can minimize the effects. Customers affected by planned outages are notified in advance.