Specifications

Surge

A surge is a short term increase in voltage, typically lasting at least 1/120 of a second.

• Cause: Surges result from presence of high-powered electrical motors, such as air conditioners and

household appliances in the vicinity. When this equipment is switched off, the extra voltage is

dissipated through the power line.

• Effect: Computers and similar sensitive electronic devices are designed to receive power within a

certain voltage range. Anything outside of expected peak and RMS (considered the average voltage)

levels will stress delicate components and cause premature failure.

Spike

Also referred to as an impulse, a spike is an instantaneous, dramatic increase in voltage. A spike can

enter electronic equipment through AC, network, serial or phone lines and damage or destroy

components.

• Cause: Spikes are typically caused by a nearby lightning strike. Spikes can also occur when utility

power comes back online after having been knocked out in a storm or as the result of a car accident.

• Effect: Catastrophic damage to hardware occurs. Data will be lost.

Sags

Also known as brownouts, sags are short term decreases in voltage levels. This is the most common

power problem, accounting for 87% of all power disturbances according to a study by Bell Labs.

• Cause: Sags are usually caused by the startup power demands of many electrical devices (including

motors, compressors, elevators and shop tools). Electric companies use sags to cope with

extraordinary power demands. In a procedure known as rolling brownouts, the utility will

systematically lower voltage levels in certain areas for hours or days at a time. Hot summer days,

when air conditioning requirements are at their peak, will often prompt rolling brownouts.

• Effect: A sag can starve a computer of the power it needs to function, and cause frozen keyboards

and unexpected system crashes which both result in lost or corrupted data. Sags also reduce the

efficiency and life span of electrical equipment.

Noise

More technically referred to as electro-magnetic interference (EMI) and radio frequency interference

(RFI), electrical noise disrupts the smooth sine wave one expects from utility power.

• Cause: Electrical noise is caused by many factors and phenomena, including lightning, load

switching, generators, radio transmitters and industrial equipment. It may be intermittent or chronic.

• Effect: Noise introduces malfunctions and errors into executable programs and data files.

Blackout

A blackout results in total loss of utility power.

• Cause: Blackouts are caused by excessive demand on the power grid, lightning storms, ice on power

lines, car accidents, construction equipment, earthquakes and other catastrophes.

• Effect: Current work in RAM or cache is lost. The hard disk drive File Allocation Table (FAT) may also

be lost, which results in total loss of data stored on drive.

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