Step 4: Choose your power
supply(ies).
There are two power supplies available for the
zl series family of switches.
Table 3. zl switch power supplies
PoE power available from the power supplies
is computed by adding the PoE power from
all of the installed supplies. If PoE power
redundancy is desired, take into account the
amount of PoE power that needs to be held
in reserve when calculating power needs.
Though installing two different power
supplies in the same chassis is a supported
configuration, it is strongly discouraged,
particularly if some level of PoE power
redundancy is wanted, since the amount of
PoE power available on power supply loss may
not be intuitive.
For example, if full PoE power redundancy is
wanted using 875 W and 1500 W power
supplies, the 1500 W supply should be held
in reserve. This would mean that only 273 W
of PoE power should be used normally. While
it is tempting to add the two supplies and
divide by two (using 585 W and keeping
585 W in reserve), if power is lost from one
supply, the full 900 W of the 1500 W supply
may be missing, with only the 273 W of the
875 W supply available. This is obviously not
enough to keep the 585 W of the normal
For no redundancy: On failure of one power
supply, PDs using PoE power equal to the PoE
power available from the largest supply
installed will have their PoE power turned
off as the power supply losing power goes
down. If after several seconds the switch
determines that there is excess PoE power
available with the remaining supply(ies), the
number of ports that can be turned back on
given the excess power available will have
their power restored.
For N+1 redundancy: If N+1 redundancy is
desired, hold the amount of PoE power
available in the highest powered power
supply in reserve.
For full redundancy: For full redundancy,
hold half the amount of PoE power available
in reserve if all power supplies in the switch
provide the same level of PoE power.
Determine full redundancy reserve power
when unlike power supplies are installed by
separating the installed power supplies into
two columns so the total power in each
column is as close in value as possible. Hold in
reserve the amount of power from the column
with the larger added power.
5
Product
number
J8712A
J8713A
1
1
Use of the J8713A changes the switch altitude specification from
15,000 ft. (4.6 km) to 10,000 ft. (3.1 km).
Supply
ProCurve Switch zl
875W Power Supply
ProCurve Switch zl
1500W Power Supply
System
power
600W
600W
PoE
power
273W
900W
Power main
requirements
110V @ 12A
220V @ 5.5A
220V @ 10A
only
