150-454-111-06
Appendix B - Technical Reference
HRE-454
February 25, 2000
29
Spare Connections
Each HRE-454 stub (with the exception of the List 3 and List 4 models) has 11 spare pairs. The HRE-454 List 3
and List 4 models provide access only to four spare pairs. On the List 3 and List 4 units, the 28 pairs have been
grouped into seven, 4-pair groups. Each of these groups passes through a ferrite coil. This design was created to
minimize the leakage of EMI energy through the stub pairs and to reduce the antenna effect that occurs when too
many spare pairs are installed in one enclosure. The red/brown pair in Group 1 is used to access the order wire
pair. The other spare pairs in both groups are folded back for easy access, if needed.
Order Wire Connections
The external order wire access port is connected to its protector by the white/black ground wire. The red/brown
spare pair also terminates on the order wire protector. This permits access to the order wire without opening the
enclosure. Simply unscrew the order wire protective cap (see
) to expose the order wire
terminals.
General Deployment Rules
The HRE-454 is an airtight enclosure. The breather vent valve on gel-filled units and the pressure relief valve on
air-filled units allow minimum ventilation to the atmosphere. This environment traps the heat generated by the
installed plugs and, in effect, causes the heat temperature to significantly rise inside the enclosure. The number of
doubler or remote units that can be housed in the HRE-454 is dependent upon the:
•
Plug type
•
Doubler version (the list number of the doubler version will also affect the number of doubler units housed
in the HRE-454)
•
Solar exposure
•
Unit orientation
lists the HRE-454 deployment rules for doubler and remote unit applications.
lists the HRE-454 deployment rules for the HLU 431 and HLU 432 applications.
The orientation column in
refer to the position of four card slots as shown in
. The horizontal orientations cause more thermal stress on the upper slots due to the chimney effect. The
chimney effect forces the heat from the lower slots to move up through the upper slots.
Even if the deployment rules are followed correctly, the metal surfaces of the installed units can feel hot when
removed from an HRE-454 that is operating in elevated ambient temperatures. This is a normal condition for the
plugs when operating in these circumstances. The plugs were designed to withstand these elevated temperatures.
When less than four slots are used, always try to leave empty slots between adjacent units. This reduces the hot
spot temperature. Also, always use the last column deployment rules when mixing units from both columns in the
same enclosure.
The tube, hex bolt, and ferrule fitting assembly is also called an Express Air Connection Fitting.
These parts are not supplied by ADC.
