SECTION 16405 UNDERGROUND ELECTRICAL DUCTBANKS AND CONCRETE ELECTRICAL MANHOLES

This spec was part of the Des Plaines, IL River WRF project that bid Feb 26, 2015.

SECTION 16405

  UNDERGROUND ELECTRICAL DUCTBANKS AND CONCRETE ELECTRICAL MANHOLES



PART 1 GENERAL

1.1 RELATED REQUIREMENTS

A. Applicable requirements of Division 0 and Division 1 shall govern work of this Section.

1.2 SCOPE

A. Provide a watertight, underground ductbank network for electrical power distribution and communication cables as detailed on the drawings and as specified herein.

1.3 SHOP DRAWING SUBMITTALS

A. Submittal drawings shall included manufacturer’s cut sheets of all equipment being provided. Submittals shall include ductbank and manhole construction drawings and details.


PART 2 PRODUCTS

2.1 DUCTBANKS

A. Conduit and Fittings
1. See Sections 16111 and 16112

B. Ductbank conduits may be HW PVC except that runs of conduits terminating at  manholes or building walls shall be galvanized rigid conduit for five feet beyond building wall or manhole.

C. Supports/spacers.
1. Acceptable Manufacturer. Condux International, Inc., (800) 533-2077.
2. Interlocking polyethylene plastic with openings for raceways and reinforcing steel. Configurations as required for ductbank configurations, conduit separations, and conduit support as indicated on the plans.

D. Bell ends.
1. Acceptable manufacturer, OZ Gedney.
2. Threaded for use with GRC.
3. Hot dipped galvanized malleable iron.

E. Concrete and reinforcing per sections 03200 and 03300.

F. Warning Tape.  Acceptable manufacturer, Thomas and Betts model NA-0708.
1. Six inch wide WBT 4 MIL polyethylene.

2. Black letters on yellow tape with the following wording continuous along tape, “CAUTION, BURIED ELECTRICAL LINES BELOW.”

2.2 MANHOLES

A. Concrete and reinforcing per sections 03200 and 03300.

B. Cast iron cover as manufactured by Neenah Foundry Co., model R-1740-D. 3’-0” diameter, round man opening with checkered top.

C. Duct terminators.
1. Acceptable manufacturer, Condux International Inc., Formex series.
2. ABS plastic, configurations as required on the plans.
3. Provide with taper for shoulder fit of conduits to terminator openings.
4. Provide with watertight locking caps.

D. Cable support channels.
1. Acceptable manufacturer, Unistrut model 3270 series.
2. Hot dipped galvanized steel channel with metal anchors 8” on center.  Mount flush with inside face of manhole wall.
3. Lengths shall be as indicated on the manhole details shown on the drawings.

E. Cable supports. Acceptable manufacturer, Unistrut. Porcelain insulators with provisions for mounting in and clamping to cable support channels.

2.3 WATERPROOFING

A. Acceptable manufacturer, Tremco Tremproof 60.

2.4 GROUNDING

A. Ground wires, ground busses, ground rods, grounding pipe clamps, and other grounding accessories as specified in section 16450.


PART 3 EXECUTION

3.1 GENERAL

A. Excavate trenches for ductbank and holes for manholes to adequate width, depth and proper slope.

B. For ductbanks, use concrete fill as specified.

C. Extend concrete envelope to finish floor grade in buildings or finish pad grade at equipment.

3.2 BACKFILLING

A. Compact backfill around ductbanks in 6" laying 90% compaction.

B. Restore areas to original conditions or as indicated on drawings after installation of ductbanks.

3.3 DUCTBANKS

A. Pitch underground ducts at 1/8" per linear foot minimum for proper drainage.  Pitch in direction as indicated on the drawings. Slopes shall be uniform along runs to prevent low pockets or irregular dips.

B. Encase ductbank conduits with minimum 3 inches of concrete cover on top, bottom and sides.

C. Complete placement of all conduits between manholes or between manhole and building prior to encasing run of conduits in concrete.

D. Top of all ductbanks shall be a minimum of 30 inches below finished grade.

E. Install conduit spacers as recommended by conduit manufacturer but not to exceed a maximum of 6‘-0” on center.

F. Anchor conduits and spacers securely to prevent movement during placement of concrete.

G. Terminate conduits on bell ends or on ductbank terminators as indicated on the plans.

H. Provide accurate locations of ductbanks on record drawings.

I. Install not more than the equivalent of three 90 degree bends between pull points.

J. Watertight caps over spare conduits shall be left in place.

K. Center cables at entrance of conduit and seal with waterproof non-hardening mastic compound.

L. Install forms on sides of ductbank if trench is not of proper firmness to prevent cave in.

M. Place concrete continuously between manholes without interruption or between manholes and buildings without interruption.

N. Place yellow warning tape six inches above ductbank during backfilling operation.

O. Minimum bending radius for 5” diameter conduits in ductbanks shall be 48”.  Minimum bending radius for 4” diameter conduits and smaller in ductbanks shall be 36”.

P. Provide all ductbank conduits with a number 12 pull wire.

3.4 MANHOLES

A. Provide porcelain cable supports in quantities required for the manhole feeders required by the plans.  Each manhole shall be provided with an additional six spare porcelain cable supports.

B. Waterproof top and sides of manhole. Apply waterproofing per manufacturer’s instructions.



END OF SECTION