OPW M2010-EU, Installation Manual

Page: 42 / 149

5.5 Probe Installation in Underground Storage Tanks
1. Install a manhole of a minimum of 18 inches (45.7 cm) diameter around an unused fitting in the top of
the tank. This manhole must be of a sufficient size to contain a weatherproof junction box together with
the probe and riser assembly.
NOTE: If the fitting is not in the center of the tank, additional measurements are required for
probe compensation.
If the fitting is not in the center of the tank more measurements will be necessary to maintain
the minimum distances between the probe and the fill and sump tubes.
2. The probe cable (OPW P/N 10-1185) is 6 feet (1.83 M) in length. Make sure there is sufficient length of
cable from the probe to where a weatherproof junction box is to be installed.
3. Leave a minimum 12 inches (30.5 cm) of extra, coiled wiring (probe wire and field wire) inside the
weatherproof junction box. The box must be large enough to contain a 0.5 inch (12.7 mm) conduit,
coiled field wiring and epoxy seal-pack, as shown in the field wiring diagram.
CAUTION: Seal-offs are required any time I.S. wiring enters conduit. Install
one conduit seal fitting in the manhole where the conduit leaves the junction
box and one in the building before the conduit goes into the console.
4. Install a 1/2-inch NPT bushing in the weatherproof junction box.
Doc. No.: M2010-EU Rev.: 13
Page 42 of 149