Protecting equipment from damage by power problems has no one-size-fits-all solution.
Discovering you've selected the wrong power protection for your electronics equipment often happens after you have lost expensive electronics hardware and/or critical data.
You may never notice that you've made a good choice if your protection devices have done their job - and saved you from a really bad day.
The kind of protection required depends on the equipment being protected and other devices already on the line. Computers may require more protection and backup than a Home Theater system. However, game systems and DVRs are basically computers. Repairs to a HDTV damaged by a power surge can cost more than replacement.
Over time smaller surges can cause a gradual deterioration of electronic circuitry.
Power Problem Causes:
Weather may be the biggest source of power problems.
Lightning and wind can seriously affect electric power before it reaches your home or business.
Accidents cause power transformers and lines to fall. Hot days can lead to power system failures. The list goes on.
Electric power varies up or down with overvoltages and undervoltages (spikes, surges, brownouts, blackouts, sags and noise). Normally, there are slight fluctuations in power. Some computers and electronics equipment are designed with limited built-in power protection. Small power sags, spikes and noise may be adequately filtered. Other less protected equipment may lack such protection and require external protection and a backup supply.
Protection and Backup:
There are 2 basic forms of power protection equipment.
1. Surge Protectors
2. Uninterruptable Power Supply (UPS) - backups
Surge Protectors are designed to limit some high overvoltages (spikes) by absorbing them. In the most common type of surge protector, a surge or spike in voltage causes an electronic component called a metal oxide varistor, or MOV, to divert the extra power into the ground wire. When the voltage returns to normal this stops. Most surge protectors also contain small chokes to help filter line noise (rapid up and down voltage.)
Once the capacity of a surge protector has been reached, it can no longer protect your equipment and should be replaced. For a large spike, a surge suppressor will give up its life to protect your equipment.
Unfortunately, surge protectors can't supply the extra power that some equipment needs during undervoltages (sags and brownouts) or total loss of power. This is an important limitation. What will happen to your computer or other equipment if you lose power?
Uninterruptible Power Supplies (UPS) are surge protectors plus a power backup. They are designed to provide protection from both overvoltages and undervoltages. They contain a battery and inverter to provide electricity to maintain or replace missing power from the normal supply.
Standby Off-line UPS :
In a standby off-line UPS, the battery and inverter backup supply is switched on in a fraction of a cycle when line voltage drops below a certain level. The transfer delay of 1.5 to 4.0 milliseconds is usually low enough for computer and electronics to ride through.
On-line UPS:
In "on-line" UPS, power is always supplied through the inverter. During a dip or loss in power, the battery fills in whatever power is needed. Equipment that is sensitive to transients, noise or cannot tolerate power interruptions may require this type of UPS. This type typically costs more and uses more power.
Factors to consider and calculate:
Equipment Load: Line Voltage. Power.
Surge Protection Levels: Clamping Voltage, Response Time, Power Absorption (Joules and Amps)
Efficiency: in %. A UPS uses some energy itself. The more % that is passed through, the higher the efficiency rating.
Surge protectors are limited in the amount of power that can flow through them and the amount of surge power they can redirect (Volts AC and Amps). The overvoltage when the protection starts is the Clamping Voltage. Maximum surge power ratings are rated in Joules and Amps. The Joules rating is a measure of the amount of electrical energy that the protection devices inside can redirect. The Amps rating is a measure of how much current can flow to ground during a spike. Surge protectors will help protect from induced surges from a lightning strike some distance away. Higher ratings indicate higher levels of protection. Direct lightning strikes near or at your building may produce pulses higher than the rating of any device - and start fires. [Data Backup and Recovery are other topics.]
In addition to Equipment Load and Surge Protection Levels, UPS maximum output power ratings are determined by the amount of power they can supply in the event of a blackout in Watts and VA (Volt-Amperes). The typical conversion formula from watts to volt-amperes is: volt-ampere = watts / (0.7PF). Consider buying a UPS that is rated higher that you equipment ratings to allow for peak currents and future growth.
Exceeding the capacity means that there probably won't be enough power to keep you equipment running properly.
Output Waveform:
Some sensitive electronics equipment requires an almost perfect sinusoidal waveform. The inverters in some standby off-line UPS produce a more rectangular wave or synthesized sine wave when supplying backup power. For most computer and electronics equipment, this form is adequate. The level of voltage distortion is often included in UPS specifications.
Battery Runtime and Life:
UPS batteries have limited power and don't last forever. The time that a UPS can continue to supply power depends on the battery type, the efficiency and the load. Limits to battery lifetime mean that you'll need to plan to replace your UPS battery eventually. Manufacturers state a normal 4 to 7 year life span for sealed lead-acid (SLA) batteries. However, actual life may be reduced from heat and active use from outages.
See our UPS Battery Replacement Guide to find the battery that fits your UPS Model.
Reliability:
Surge protectors and UPS are electronic devices. They have their own limitations and failure rates. You can reduce the risk of failure by choosing protection devices from manufacturers that use better design, better parts and better quality control.
You can't eliminate the risks from power problems.
Reducing them makes sense.
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