UPS Maintenance Bypass Switches

Automatic Static Bypasses and Manual Bypass Switches for UPS Systems

Online uninterruptible power supplies from 6-10kVA upwards will have an automatic UPS bypass (static bypass) and an internal service bypass. This internal service bypass allows the UPS to be inspected and maintained without disruption to the load but with internal power supplies present.

An external manual bypass is different and is a manual bypass switch that allows the UPS to be fully and safely isolated from any upstream AC supplies, whether this is the mains power supply or a standby power generator.

Maintenance bypass switches also allow an uninterruptible power supply to be completely removed from the critical power load circuit without interruption to the load. This can be necessary when completing a UPS swap out or replacement with a new UPS system.

Manual bypass switches are an important accessory to any UPS installation, allowing the safe service of a UPS system. External maintenance bypasses require manual switching (circuit breakers) to isolate the UPS and safe the load from any form of power supply disruption.

Rackmount UPS Maintenance Bypasses

These are stocked rack mount maintenance bypases. Custom builds are available on quotation.

Wallmount UPS Bypass Switch

These are stocked wall mount maintenance bypases. Custom builds and larger bypasses for UPS above 100kVA 3/3 are available on request.

UPS maintenance bypasses are available in several formats. It is important to select a UPS maintenance bypass according to the uninterruptible power supply it is to be used with in terms of maximum Amperage required, phase configuration and Input/Output configuration. The principle considerations when selecting a UPS maintenance bypass switch include:

• Rating: the bypass must be rated to be equal to (or less than) the total output rating of the UPS in kVA or Amps. For a 2kVA UPS this means selecting UPS that can supply 2kVA or less.
• Input and Output Supplies: the bypass switch must match the UPS installation mains power supply and load phases. Most single-phase UPS are configured 1/1 where the input and output is single phase but a 3/1 configuration denotes a three phase input and single phase output. A three phase input and output is referred to as a 3/3 installation.
• Mains Power and Load Connections: Most installations up to 3kVA will have plug and play connections and make use of IEC320 C13 and C14 cables. Hardwired inputs and outputs are an option for UPS maintenance bypass switches 3kVA and below. Above 3kVA installations typically require hardwired connections and therefore installation by a suitable qualified electrician or electrical contractor.

An external maintenance bypass can also be important performing a generator service.

Custom Bypass Panels and Switchboard Designs

If a project requires custom bypass panels or manual bypass switches, these can be designed and once approved manufacture within 10-15 working days. Custom options include interlocking (Castell), volt-free signal contacts for remote monitoring, built-in panel meters and LCD panels, a local power sockets for service engineer use, and parallel UPS operation. Bypasses may also be supplied with additional protection including lighting and surge protection. Custom panels can also be painted to virtually any specific data centre colour schemes.