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6
POWER PROBLEMS
AND THEIR ASSOCIATED CAUSES
All electrical and electronic equipment, connected to the
mains supply is at risk of being damaged from spikes, surges,
lightning, brown-outs, power-cuts (blackouts), power back
surges, and over-voltage. The following is a summary of the
main types of power problems, causes and how these affect
electrical and electronic equipment.
Spikes/Surge:
Very short, (one millisecond) event of very
high surge in voltage to thousands of volts and amps. Spikes
are common in all parts of the world and repeated exposure to spikes
will damage electronic equipment and corrupt data.
What causes it?
Switching on/off of nearby equipment, lightning,
motors starting etc.
RFI (Radio Frequency Interference)/Noise:
High frequency
disturbances that occur within a short period of time
(milliseconds). RFI & noise are very common in all parts of the world
and are the main cause of data corruption.
What causes it?
Generated by high frequency noise from nearby
equipment like TV, radio equipment, transmitters, mobile phones,
switching on/off of certain loads, fluorescent lights, motor speed
controls, light dimmers.
Over-Voltage:
Long duration (milliseconds, seconds, minutes,
hours or days) rise in the voltage above acceptable limits.
Depending on the level of the over-voltage, the damage can be
instantaneous, severe and irreparable.
What causes it?
On return of mains supply after power cuts, under-
sized utility oscillating between periods of brown-outs and over-voltage
or accidental (e.g. accidental connection between two phases).
Brown-Out:
Long duration of low voltage (milliseconds to
seconds, minutes, hours or days). Very common in parts of
the world especially where the power utilities are over-stretched.
Prolonged and frequent brownouts cause the equipment to malfunction
or not work at all. Repeated episodes are certain to cause damage.
Motors and compressors (and therefore fridges, freezers, coolers, air-
conditioners and pumps) are especially at risk. In time, damage is
certain.
What causes it?
Most commonly an over-stretched utility, especially in
areas of poor power distribution infra-structure and remote areas.
Common in dry seasons where water is used for electricity generation.
Basic Lightning:
Direct or nearby strikes can cause minor
problems or severe disturbances and damage. Lightning
produces spikes/surges, over-voltage or power cuts.
What causes it?
The surge is generated by either a direct hit, or
indirectly striking underground or overhead lines and transmitting high
surges to connected equipment in nearby buildings.
Power-cuts:
Common in many countries in the world,
especially in areas of frequent voltage problems. Sudden loss
of power can cause damage ranging from corruption of data to
mechanical faults as equipment is stopped while in operation.
What causes it?
Power or sub station failure, breakdown in the
distribution network, or simply a plug being pulled out accidentally.
Power-Back Surges:
These typically occur when power
returns after a power-cut and connected equipment receives
a surge of electricity at an over-voltage level, which can be very
damaging (see above).
What causes it?
Power back surges are created by the utility, when it
restores supply at an above normal voltage in order to compensate for
the demand as connected equipment re-starts simultaneously.
Telecom surges, spikes and lightning:
Short term, high
voltage and current phenomena occurring on the telephone
lines. Can cause irreparable damage to any piece of equipment
connected to the incoming line. The telephone line itself may even be
damaged or destroyed in severe cases.
What causes it?
Telecom spikes are caused by lightning striking either
the telephone line directly or an object near it.
