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ITGlossary · Protection and installation
Overcurrent Protection
A system designed to interrupt excessive current to protect UPS and loads.
Technical level:Intermediate
Every UPS and every electrical installation has a limit to the current it can carry safely. Overcurrent protection detects when the current exceeds that limit and opens the circuit before cables, semiconductors or batteries overheat. It is provided by fuses, miniature circuit breakers, thermal elements or electronic circuits inside the UPS itself.
During installation, the breaker feeding the UPS must be sized for its input current, including battery charging. Selectivity matters too: the protection on the outputs should isolate a fault without bringing down the whole system.
A common mistake is replacing a fuse or breaker that keeps tripping with a larger one. If the protection trips, look for the cause, such as an overload or a fault.
Related terms
- Circuit ProtectionDevices such as fuses and circuit breakers that open the circuit on overcurrent or short circuit to prevent damage.
- Emergency Power Off (EPO)A safety feature that allows immediate shutdown of power to connected systems in an emergency.
- Ground FaultAn unintended flow of current from a live conductor to earth or to a device’s metal casing.
- IK Rating (Impact Protection)Scale from IK00 to IK10 under IEC 62262 that shows how much impact energy the enclosure of an electrical device can withstand.
- IP Rating (Ingress Protection)Two-digit code under IEC 60529 in which the first digit shows protection against dust and solid objects and the second against water.
- Operating Temperature and Humidity RangeThe limits of room temperature and relative humidity within which a device is designed to operate correctly.