When the UPS input circuit breaker is open, the UPS is not connected to the upstream power system, and therefore to the supply service, through any circuit conductors other than those used for grounding and bonding.
Does my ups need a grounding system?
Without a properly installed grounding system, your UPS won't function correctly. A grounding system allows circuit protection to clear a ground fault, and provides paths for diverting surge current away from the UPS and for removing undesirable currents from the critical load. So what can you do to ensure your grounding system allows your UPS
Why do I need a grounding system?
A grounding system allows circuit protection to clear a ground fault, and provides paths for diverting surge current away from the UPS and for removing undesirable currents from the critical load. So what can you do to ensure your grounding system allows your UPS Your UPS is only as reliable as your grounding system.
How do you ground a ups enclosure?
Essentially, the UPS enclosure must be connected to ground through the building's grounding-electrode system by way of a grounding electrode conductor. This connection in an ungrounded system serves as the grounding reference point for all conductive equipment in the ungrounded system that does not carry current under normal conditions.
Typically, the grounding point is a copper bar mounted on insulators in the electrical room and bonded to the local building steelwork. Whenever you use a delta-connected supply for a UPS system, you must create an artificial neutral. In such cases, a three-resistor network typically provides a logic reference point for the bypass input.
The same condition will exist in a UPS system with a (single) battery ground fault. The unit will continue to run, but a battery ground leakage detection monitor will sense the ground current, and then can trigger an alarm on the monitor, and/or through a “building alarm” in the UPS.
The same grounding-electrode system used for the building as a whole must also be used for any separately derived systems, as per NEC 250.58, so all that is required is a connection between the building's grounding electrode and the UPS enclosure through a grounding electrode conductor.