Vertiv Liebert PPC - Output Power Connections

Vertiv | Liebert
®
PPC
™
User Manual | Rev. 6 | 03/18 | 24
1.3.5 Output Power Connections
Output circuit breaker(s) and/or panelboards with ground and neutral provisions are provided inside the unit for
connecting load(s) as required. (See Figures 6, 8 and 10.)
Flexible output distribution cables for use in data processing areas under a raised floor are optional and may be
factory supplied. Cable lengths and layout should be well-planned:
• Cable access—Cable routes should follow aisles between equipment. This will facilitate access to cables for installation,
routine inspection, and future changes.
• Cable length—Measure the distance to the load equipment following right-angle paths, rather than diagonally or directly.
Always measure to the extreme far side of the equipment with respect to the unit to insure adequate cable length.
• Air circulation—Prevent restriction of airflow under the raised floor by running the flexible conduits flat on the sub-floor, in
parallel paths.
For best performance, the Liebert PPC should be located as close to the load as practical.
Initial system output loading should be between 50% and 75% of rated capacity. This allows the addition of future
loads without immediately investing in another power conditioner. The high partial-load efficiency of the unit
permits such sizing without imposing an energy-use penalty during initial operation.
Keep the load balanced—Balancing of loads is good design practice on any 3-phase system. Accordingly, each
distribution panel is load-balanced at the factory, based on output branch circuit breaker sizes. All additions to
the system should be arranged so as to preserve this balance.
To ensure proper harmonic current cancellation on phase-shifted, multi-output units, the loads should be
balanced across the multiple outputs as well. For example, with a dual-output unit, the loads should be balanced
across the six output phases. For a quad-output unit, the loads should be balanced across the 12 output phases.
Code compliance—All output cables and connections must comply with the NEC and all other applicable codes.
Padlock-off provisions—All output cables without receptacles that are hard-wired to the load equipment must
be equipped with a padlock-off accessory for the output circuit breaker. The padlock-off accessory is to be used
to lock-out and tag the circuit breaker when service is performed on the hard-wired load equipment in
accordance with OSHA safety rules.
WARNING
Risk of electric shock. Can cause injury or death.
Verify that incoming line voltage circuits are de-energized and locked out before installing output
breakers and cables.