Operation Instructions
MBE35_50 OPERATION MANUAL 2005_10
48
To lessen the stress and abrasion of the loop wire the 90
°
corners shall be cut at a
45
°
angle or a core drilled with a minimum of 1.5” diameter (See drawings below).
5.4.3 Loop Lead Wires
The loop lead-in wire has a significant role to the functionality of the loop.
Following are some important points for installing loop leads:
The loop lead-in wire must be twisted about 7 times per ft up to the point where the
wires connect to the detector.
Leads of multiple loops should not use the same cable or conduit. If it is not possible
to have separate conduits for multiple loop leads, a shielded twisted-pair wire must be
used for each loop.
The lead-in length should not exceed 50 feet.
Long leads can decrease the sensitivity therefore, the leads should be as short as
possible.
Note:
It is necessary to cut the leads to the proper length. Excessive long leads
looped before it is wired to the detector will decrease the loop functionality.
Do not run a loop lead through the same cut of another loop:
Overlapped cuts
45° angles to
prevent sharp
corners
Lead-in
wire
Lead-in
wire
Core hole in all four
corners
☞
LO
O
P
LO
O
P
LO
O
P
WRONG
CORRECT
LO
O
P