Dlm Touch Current Compliance; Choosing A Ups - Dell EMC DLm8500 Data Domain Physical Planning Manual

Environmental specifications and regulatory compliance

DLm touch current compliance

Choosing a UPS

Disk Library for mainframe 5.0 Physical Planning Guide for DLm8500
40
DLm is designated as a fixed (stationary) electrical equipment with high earth-leakage
markings. Connect the cabinets to the AC supply with the recommended rated current
breakers and the attached cables. The "DLm power requirement" sections for
DLm8500 with Data Domain
with VMAX (DLm power requirements
recommended circuit breaker ratings. These recommended breaker ratings are based
on the maximum kW loading of the cabinet and not on the kVA figures of a particular
configuration. The kVA values listed in this manual are intended for air conditioning
and utility loading purposes only. The "Power and cooling data" sections for DLm8500
with Data Domain (Power and cooling data
(Power and cooling data
Because DLm systems are high earth-leakage devices, differential trip devices
(typically 30 mA) are not recommended due to random activation during utility feed
distortions and power line transients interacting with the cabinet noise filters. These
differential devices have trip ratings of 5 mA to 500 mA and are mostly intended for
consumer goods rather than fixed devices.
If the DLm cabinet is correctly grounded to the AC power source, leakage current not
produces a voltage leading to electrical shock. Serious insulation breakdowns trip the
breakers feeding the cabinet or, preferably first clear fuses in individual internal
modules closest to the fault.
The VTEC and Storage Controllers (Data Movers) are stateless, so no battery backup
is required. In the event of a power failure, the Storage Processor writes contents of
the write cache to disk, before shutdown. Although DLm does not require a battery
backup to ensure data integrity, to avoid potential downtime, purchase a UPS from a
qualified vendor.
EMC neither offers nor recommends any specific UPS suppliers or product type to its
customers. However, EMC uses preferred suppliers for UPS systems in their facilities.
Therefore, if you, the customer, are implementing a UPS, EMC recommends the
following:
When you are planning the UPS solution for a DLm and the host system is
l
presently (or will potentially be) protected with a UPS, the battery backup time
you propose for the DLm UPS solution should match that of the host system.
The DLm requires independent zone B and zone A power feeds for each cabinet.
l
The UPS should be equipped with an internal output isolation transformer.
l
The UPS should be installed as a separately derived AC source using neutral and
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ground wiring to preserve the fault tolerance specification of the DLm power
system.
Depending on the power requirements for your DLm system operation, an isolation
l
transformer/stabilizer installed in front of the UPS could further buffer the AC
utility environmental factors from reaching DLm. To determine if an isolation
transformer/stabilizer is needed, consult a licensed electrician.
(DLm power requirements
on page 33) provide details of the
on page 26) and DLm8500 with VMAX
on page 35) contain detailed information.
on page 25) and DLm8500