LOOP DETECTOR SECTION 846
529 SECTION 846 — LOOP DETECTOR
846.1Description.
This work consists of providing and placing loop detectors.
846.2Materials.
B.Backer Rod, Closed Cell Section 1043
C.Conduit, Galvanized Section 1062
D.Loop Detector Section 1079
E.Tape Section 1074 .2.F
F.Heat Shrink Tubing Section 1074 .2.G.1
G.Loop Wire Section 1079.1
H.Home Run Cable Section 1074 .1.D
I.Backer Rod – 5/8-inch closed cell foam. Section 1043
J.Junction Well Splices Section 1074 .2.G
K.Splicing Kit Section 1074.2.G .3
L.PCC Patching Section 1023
M.Asphalt Production Section 1014
N.Joint Sealant Section 1042.1.B
846.3Construction.
846.3.1 Loop Wire Installation.
A.Sawcut a groove in the pavement 5/8 -inch wide and at least 3 1/2 -inches deep in accordance with
compressed air to remove loose material before sealing.
B.Install the loop detector wire using blunt tools to prevent damage to the polyethylene outer
cover.
C.Tag 1 end of a loop detector wire to indicate start with an “S.”
D.Place a 5/8 -inch backer rod on top of the wire in the saw cut as needed to secure the wire within
the saw cut.
E.The engineer may require a high voltage ground test with a 500 volts DC megger after completion
of the loop detector installation and before sealing saw cuts. If the resistance to ground is less than 100 megaohms, remedy the work.
F.Apply a sealer, and sealer accelerant or retarder, if necessary, in the saw cut, in accordance with
the manufacturer’s directions. Protect the saw cut area from traffic until the sealer has set. Place a minimum of 1 inch of sealer on top of the loop detector wire and finish flush with the pavement. Seal any drilled holes in the pavement.
G.Install 2 loop detector wires in a saw cut from the loop to the edge of the road. Extend these 2
wires from the end of the saw cut to a junction well. Twist the wires a minimum of 5 wraps per
Source: Delaware Standard Specifications for Road and Bridge Construction, 2025 Edition. Pages 539–539 of 779.