Specifications

2
Dip (Sag): is a short term decrease in line voltage.
Usually it results from a short circuit in the power line or a sudden
increase in electrical load on the line (start up of large loads), utility
switching or equipment failure.
Surge: is the exact opposite of a dip. It is a temporary increase
in line voltage that lasts at least one cycle (approx. 16mS).
It can be triggered off by rapid reduction in power loads or by
utility switching.
Spike (transient): is similar to a surge except that it lasts
less than a full cycle (often only a few milliseconds).
It can be 100% or more above nominal voltage.
Electrical Noise: probably the most common type of disturbance,
which is a random high voltage, or high frequency interference on
the power line caused mostly by non-linear loads. There are two
types of noise, usually referred to as common mode (noise
between power connection and ground) and transverse mode
(noise between power connections).
Brownout: is a deliberate reduction in AC line voltage by the utility
company during periods of unusual high demand or insufcient
load capacity. The power line supply does not have the full capacity
to supply the load which results in load sharing.
Equipment
Available
Automatic
Voltage
Regulator(AVR)
Line
Conditioner
OfineUPS Line
InteractiveUPS
TrueOnlineUPS Frequency
Converter
Surges
Limited
Protection (MOV)
Full
Protection
None or Limited
Protection (MOV)
Limited
Protection
Good
Protection
Good
Protection
Spikes
Limited
Protection
Full
Protection
None or Limited
Protection (MOV)
Limited
Protection
Good
Protection
Good
Protection
Sags
Good
Protection
Full
Protection
None or Limited
Protection
Limited
Protection
Full
Protection
Full
Protection
Noise
Limited
Protection
Good
Protection
None or Limited
Protection
Limited
Protection
Good
Protection
Full
Protection
Blackout
(Power
Failure)
No
Protection
No
Protection
Good Protection
4ms-8ms
Changeover
Good Protection Full
Protection (no break)
No
Protection
Frequency
Variation
No
Protection
Good
Protection
No Protection Limited
Protection
Full
Protection
Full
Protection
Waveform
Distortion
No
Protection
Good
Protection
No Protection Limited
Protection
Full
Protection
Full
Protection
CableSize ArmouredCable
FreeAirWired
UnarmouredCable
FreeAirWired
2.5mm2 27 Amps 24 Amps
4.0mm2 35 Amps 32 Amps
6.0mm2 43 Amps 41 Amps
10mm2 60 Amps 55 Amps
16mm2 70 Amps 72 Amps
25mm2 100 Amps 94 Amps
35mm2 125 Amps 115 Amps
CABLE SELECTION CHART
CableSize ArmouredCable
FreeAirWired
Unarmoured
CableFreeAirWired
50mm2 150 Amps 140 Amps
70mm2 180 Amps 175 Amps
95mm2 225 Amps 215 Amps
120mm2 260 Amps 250 Amps
150mm2 290 Amps 280 Amps
185mm2 340 Amps 330 Amps
240mm2 400 Amps 385 Amps
Below is a table of power problems and how to solve them.
Blackout: this is the ultimate power disturbance. It is a complete
cut in the power line supply (power failure). Typically described
as “zero-volt” condition lasting longer than half a cycle.
Can be caused by utility equipment failure, lightning etc . . .
the list is long.
Businesses are becoming more and more reliant on a utility
power supply that is pushed beyond its capacity. Despite
advances in the capabilities of modern personal computers,
a momentary power outage is still all it takes to lose your data.
More dangerous is the loss of previously written les, or even an
entire hard disk, which can occur should a power problem strike
while your computer is saving a le. Network le-servers
constantly writing to disk are particularly susceptible.
Some African countries, including South Africa, have resorted
to power rationing as a way to meet increasing demand.
In these cases, the question of whether or not to use power
conditioning, is no longer a choice.
HOW POWER PROBLEMS CAN BE AVOIDED
POWER LINE DISTURBANCES