Clark Public Utilities — Residential Electric Service Handbook

Figure 7 Typical secondary trenches to underground utility sources

secondary trench to transformer number existing padmount transformer NOTE: Clark Public Utilities personnel will route wire into energized facilities.

#### OF transformer lock FRONT TRANSFORMER leave 10 ft. tail of triplex wire at transformer

use the utility provided 3 ft. white paint mark to position trench (or use transformer lock if mark is not shown)

secondary trench tosecondary secondary trench pedestal to existing secondary pedestal

NOTE: Clark Public Utilities view from side personnelNOTE: will Clark route Public wire Utilities VIEW FROM SIDE into energizedpersonnel willfacilities. route wire VIEW FROM BACK 2 ft. to into energized facilities. 2-1/2 ft. open view from back 8 ft. of makeup wire 3 1/2 ft. open trench 1018 ft. in. of makeupminimum wire cover 12 in. to top of conduit 3 ft. 18 in. minimum cover to top of conduit 24 in. 2 ft. trench depth

3 ft. 24 in. trench depth conduit aimed at center of pedestal (leave 3 feet between end of conduit & pedestal) bushing required, 6 in. do not permanently conduit aimed at attach to conduit conduit coupler required, do not 6 in. center of pedestal permanently attach to conduit (leave 2 feet between end of conduit and pedestal)

Chapter 3: Underground Secondary Services / January 2015 n 17 Clark Public Utilities — Residential Electric Service Handbook

Figure 9 Secondary voltage overhead to underground pole bracket installation

coil triplex wire at base of pole for future connection by utility crews pole heights will vary, check bushing required, with your utility representative do not permanently for wire length required attach to conduit power pole pole bracket and clamp 6 in. installed by a utility representative (do not relocate) FINAL GRADE

conduit must 18 in. minimum be installed 24 in. cover to top vertically plumb trench depth to pole of conduit (as needed) schedule 80 conduit extension seated in pole 24 in. radius, 3 in. schedule 40 3 in. schedule 40 bracket clamp 90 degree elbow

NOTE: Trench depths vary; review your utility-provided design for required depth.

Additional trenching and conduit installation tips

The following general tips will help to ensure that projects run as smoothly as possible and may answer additional questions about trenching and installing conduit. #Dig trenches in straight lines to the greatest extent possible. #Schedule the trenching so the trench is open for the shortest practical time to avoid creating a public hazard and to minimize the possibility of the trench collapsing due to other construction activity, rain, etc. #If any conduits, wires or pipes are encountered while digging, leave them covered. #If rock or other extremely difficult digging is involved, contact your Clark Public Utilities representative to discuss the situation. #Prior to backfilling, the appropriate jurisdiction will inspect the trench for adequate depth, conduit and cable placement. If corrections are necessary, a second inspection is required after all corrections are completed. #After backfill, tamp the soil, leaving a slight mound to allow for settling.

20 n Chapter 3: Underground Secondary Services / January 2015