New technology devices and IT based equipmens are requires uninterruptible power and well regulated voltage and frequency.
At a lot of applications UPS devices are used for uninterruptible power, but on electrical distrubition wiring inside of the building some risks are always possible. (fuse failures, burned cables ,wrong usage of circuit breakers etc..)

Burned fuses, thermal circuit breaker failures
Wrong usage of circuit breakers
Cause of high voltage or high current at electrical systemn burned wires or electrical components
Any device failure can cause big currents on distrubition sysem

To reduce these type of risks is to use an STS device near the critical load which monitors two power lines and select the best power source for critical device.

About STS

Application at figure 3 electrical wiring zones are (A,B,C) showned these are:

A) All possible power failures effects this zone (short voltage outages,fuse failures, wrong usage of circuit breakers etc..)
B) This zone is open for all power failures without voltage outages (fuse failure, wrong usage of circuit breakers,burned cables..)
C) Most SECURE ZONE power supplied by STS devices

TESCOM STS units selects the better power line and transfers the critical load immediately to the good power line without any intteruption.