What are the bypass arrangements for a 3-phase UPS?

A 3-phase UPS system will have a built-in automatic bypass for overload and fault conditions. The bypass will generally be a static bypass rather than a relay-based bypass. The UPS will also have a built-in maintenance bypass to allow the UPS to be isolated for maintenance by a manufacturer certified engineer. The UPS installation may also have an external wrap-around UPS bypass switch. This allows the uninterruptible power supply to be fully powered down and if necessary swapped-out, without disruption to the connected loads. The external bypass switch may use a rotary switch or breaker arrangement.