Electrical construction work must adhere to the contract documents which commonly include proposal notes, project plans, ODOT’s Construction and Material Specifications, applicable electrical codes and industry standards.
The following information does not alter or supersede the contract documents but should be considered as a guide for those involved.
When questions are raised regarding project plans and specifications, the project inspector or engineer should address the issue by following these steps.
If the issue affects other portions of the project, the ODOT project management team should consult the designer to ensure the project will meet the performance goals of the lighting system. The designer should also be consulted if the intent of the plan is unclear. Plan discrepancies that involve site conditions can usually be resolved without involving the designer. If the designer is unavailable, someone with extensive knowledge of ODOT lighting standards and electrical systems should be consulted.
ODOT contractors are prequalified for specialized work types. They bring expertise to the project and an independent perspective from the project management team. As the contractor reviews plans and specifications, he wants to ensure that he can install material that will ultimately operate as the designer intended. The contractor relies on inspectors and engineers to approve materials and work plans to guide the project installation and ensure that he will be paid for work completed.
The first requirement of the Contractor is to notify all utilities before construction work begins. Names and addresses of these utilities are given in the project plans. It is also the contractor’s responsibility to contact the Ohio Utility Protection Services (1-800-362-2764) to have utility locations marked in all areas where digging is involved.
Supplemental documents are used to verify that the material installed meets the minimum criteria established by ODOT. Highway lighting items are found in Section 625 of the ODOT Construction and Material Specifications (CMS). Section 725 contains detailed descriptions of acceptable materials.
In general, all materials furnished shall be new and of first quality (unless otherwise noted in the plans) and shall be identified by either a permanently attached name plate or by an indelible marking. Before any construction work begins all material shall be checked to determine if catalog numbers and dimensions correspond with those shown on approved certified drawings. Any material deviations from that already submitted will not be permitted to be used until a new catalog cut is submitted and approved. Whenever practical, like items of electrical equipment shall consist of products of the same manufacturer.
No materials furnished shall contain Polychlorinated Biphenyls (PCBs). Transformers, ballasts and capacitors shall be marked “No PCBs” in accordance with Federal Environmental Protection Agency regulations.
Four material certification procedures are commonly used to ensure approved materials are installed.
The contractor should not order any items before material submittals have been reviewed. The contractor shall submit two copies of shop drawings or catalog cuts prior to their installation as required for Department records. These submittals ensure that the material to be installed on the job meets minimum criteria; the State has records of the material installed; and, if necessary, an identical piece of equipment can be purchased to match material installed on the project.
Each submittal shall identify the project and bid reference number under which the item is being installed and clearly mark each item by circling or underlining the material to be installed. If a given item is listed under multiple bid item reference numbers, separate and complete documentation packages shall be made for each bid item. If multiple items are incorporated under a single bid reference number, submit all interdependent items together. The contractor’s cover letter certifies in writing that each manufactured item conforms to all contract requirements for that item.
It should be noted the submittal of certified drawings does not relieve the Contractor from furnishing, when requested, additional catalog information for materials as deemed necessary for the project.
ODOT Plant Sampling and Testing Plan (TE-24 system) is administered by the Office of Materials Management. This system was designed for materials to be sampled, tested, approved and stocked for future use on ODOT projects. Materials are inspected at the manufacturing or distribution site. Each approved lot of material is assigned a TE-24 certification number. The TE number can be transferred directly to an ODOT project or it can be transferred to other warehouses, such as a contractor’s storage facility, then transferred to a project at a later date.
TE-24 certification is available for the following 625 electrical items.
Section 625. Lighting Items Available with TE-24 Certification
In 2002, the Office of Materials Management instituted a program for handling certain materials with a Qualified Products List (QPL). Items included on the QPL will not require a TE-24 being sent with the material to the project. QPL materials should have a direct, easy means of identification that mark the material and link it with the manufacturing company. Acceptance of QPL items will be at the ODOT project level. ODOT project personnel will automatically verify pre-approval on the QPL list through ODOT’s computer construction management system.
Qualified Products Lists include the following electrical items. For a current list of approved products, contact the Office of Materials Management.
Material which does not require shop drawings typically requires other certification that it meets ODOT criteria; however, some material does not require any special supporting paperwork. The following items are normally manufactured to standards that meet ODOT criteria and do not require special documentation. Visual inspection of these items may be used to verify their compliance.
Section 625. Lighting Items with NO Submittal Requirements
Only contractors prequalified by the ODOT Office of Contracts shall be allowed to complete electrical items of work on any project. Work Type 43 - Highway Lighting is required to perform electrical work on lighting.
CMS 725.11 defines a luminaire to include the direct appurtenances such as a housing, lamp, support clamp, reflector, refractor, socket, ballast and terminal block.
In all cases, prior to installing a luminaire, check to see that the ballast rating is compatible with the circuit voltage, and that the lamp wattage and distribution type is as specified in the plans.
Light Distribution Readjustment
Light distribution is normally factory preset to customer order. Check settings against the distribution stipulated in the plans and follow instructions packed with the luminaire for changing if required.
The conventional luminaire used by ODOT is an “ovate” or “Cobra Head” type fixture with a domed glass lens. Check to determine that the socket setting is correct and will produce the I.E.S. distribution type as shown on the plans. Also, check the socket setting for compliance with the instruction sheet packed with each luminaire.
Conventional Style Luminaire Leveling
After installation of the luminaire, determine that the luminaire is properly leveled according to the instructions packed with the luminaire.
This luminaire is usually set back from the edge of pavement. All luminaires are the same except for the size of the lamp.
Caution shall be taken to insure that the correct style tower lighting luminaire is installed as designated in the plans. The three (3) types of tower luminaires are:
When installing the asymmetrical type luminaires, a check shall be made to determine that the glass refractors are properly oriented. Symmetrical luminaire refractors have a circular distribution which doesn’t require orientation.
Low-mast luminaires are installed on median barrier wall with L&N Type I asymmetric luminaires or omni-directional fixtures at approximately 50-foot (15.25 m) height. Fixture assembly should be uniformly installed when viewed from the major route.
Underpass luminaires, whether post top or wall mounted, shall have the glass refractor protected by a wire guard or shield. A 6"x6"x4" (150x150x100 mm) junction box is typically provided near each fixture for pulling wire.
The following four mounting techniques are determined by the designer based on light location relative to the bridge pier or abutment and the height of the structure.
Wall mount underpass luminaires are standard wall pack fixtures attached to the structure.
Pendant mount fixtures are installed by using an 1-1/4" (32 mm) drop pipe to suspend the fixture below the structure to provide the desired lighting height.
Post top mounting of an underpass luminaire takes place between two structures. The fixture is coupled to the ground mounted or median mounted post with a slipfitter. Pole style is shown on HL-10.11.
Ceiling mount underpass luminaires are attached to the underside of the bridge structure. Fluorescent fixtures are typically ceiling mounted.
Post top luminaires are used in rest areas, picnic areas and other off-road lighting applications. These luminaires are installed on poles with breakaway transformer bases as shown in HL-10.11.
Lamp type and wattage should be checked for compatibility with ballast. Lamp installation should ensure full contact of the base with the socket.
Check 150 watt HPS lamps to determine they are of the 100 volt design meeting the requirements of ANSI-S-56. The electrical characteristic for the S56 type ballast requires a 100 volt lamp and is not electrically interchangeable with 55 volt lamps.
The small Style A luminaire shall use 70 watt and 100 watt HPS lamps.
The medium Style B luminaire shall use 150, 200, 250, 310 or 400 watt HPS lamps.
The large Style C luminaire is no longer used in new installations due to improved lighting efficiencies in smaller housings. This size is only used for 1000 watt Mercury Vapor lamps.
Poles should be inspected when received, if possible, or prior to erection. General dimensions should be checked, including pole length, support height, base diameter, top diameter and wall thickness. Also check bracket arm length and style. Wall thickness is most easily measured with calipers at the top end of the pole. Check base plate dimensions including thickness, bolt circle diameter and bolt hole size.
The galvanizing on poles shall be inspected visually as soon as possible following delivery. The galvanizing should be inspected externally and internally for flaws and imperfections in daylight or strong artificial light. Poles are to be loaded, transported, unloaded, stored and erected in a manner avoiding damage to the galvanizing. Supports stored in the field should be kept off the ground to prevent the galvanizing from contacting water which may result in a premature oxidation condition. The galvanizing should have the appearance of a uniform application. Poles should be checked for assurance that the following flaws or imperfections do not exist.
Loose or bare spots in the galvanizing where improper preparation has prevented metal adherence in the molten zinc bath. Poles shall be rejected if the point of a penknife can flake off the galvanizing layer.
Excessive galvanizing faults and imperfections or general poor workmanship may be cause for rejection of the support. Gross imperfections may lead to the suspicion of inadequate protective cover and may require inspection with a magnetic instrument. Minor scratches in galvanized surfaces can be accepted.
All welds on poles should be inspected visually as soon as possible following delivery. Inspect for flaws and imperfections under good lighting conditions using a magnifying glass as necessary. Evidence of any of the following faults or other imperfections such as warping and misalignment may be cause for rejection of the pole. The following features of welds should be checked.
When steel poles are used with aluminum transformer bases, both the bottom of the pole anchor base and the top of the transformer base shall be painted with a zinc rich paint meeting Federal Specification TT-P-641-Type II.
Prior to installation, anchor bolts shall be checked to determine if nuts can easily be turned on the threads by hand.
Handhole covers for light poles and transformer base covers shall immediately be applied after erection of the pole. A light amount of anti-seize or grease lubricant shall be applied to all screws for handholes covers, splice box covers and bolts for transformer base doors.
Light poles shall be plumbed after erection. Shims for the purpose of leveling are supplied by the pole manufacturer. Some contractors will install the transformer base first before setting the pole, while others will attach the transformer base to the pole before erecting. Whichever the case, shimming and plumbing of the pole, shall be a final requirement.
Check that the cable grip in the light pole is properly installed as shown in HL-10.12 to prevent damage to the pole and bracket cable.
Circuit identification decals shall be located approximately 7 feet (2.1 m) above the pole base facing the oncoming traffic. (Same location for light towers).
Tower shafts typically consist of not more than four round or multi-sided tapered steel sections for shafts up to and including 100 feet (30.5 m) in length, five sections between 101 thru 120 feet (30.8 thru 36.6 m), and six sections over 120 feet (36.6 m).
The pole, once received in the field, should be carefully inspected for piece marks. Lap joints shall he not less than 1 ˝ times the diameter of the shaft at the joint, measured at the minimum diameter of the inner telescoping section. The sections are positioned horizontally on blocks and assembled according to manufacturer recommendations.
Lifting and setting of a tower should be by crane with the hoist line attached at a point as far above the center of gravity of the tower as possible. Care should be taken to ensure that the pole is structurally capable of accepting stresses induced at the lifting point or points. Any hoisting must be smooth and continuous without abrupt jerks.
Poles with more than one section shall be erected by either lashing the joints securely together or by using a tethering cable secured to the base of the pole.
Do not depend on the lowering device cables to secure slip-joint type pole sections together.
Make sure the leveling nuts are level before setting the tower. When the pole has been lifted, the base should be placed over the anchor bolts. The crane must support the pole until the nuts are securely placed on the anchor bolts.
Handhole doors on towers shall close with no excessive gaps. Handhole door locks, when specified, shall be provided with keys that are interchangeable keys with other tower handhole doors.
As far as practical. light towers shall be plumbed early in the morning when there is minimum heat effect from the sun and when there is no appreciable wind. The heat from the sun on one side of the pole can cause a visible bow to occur.
After the tower has been set and plumbed, the space between the top of the foundation and the bottom of the tower base plate shall NOT be grouted. A stainless steel ring may be installed around the base of the pole to keep out grass and rodents when specified.
Lightning protection system details are found in HL-10.31.
The lightning ground cable shall comply with the requirement of 725.16. No splices are permitted between the air terminal mounting bracket and the ground rod. Since this cable is installed before the tower is erected, it is important that enough cable be provided at the bottom of the tower to enable the cable to be fished through the foundation conduit. Extra cable shall also be provided when a maintenance platform is required.
A tapped hole at the base of the tower with a ˝-13 (13x1.95 mm) galvanized bolt and washer shall be provided for attachment of equipment grounds. This nut is provided at the base plate for connection of the jumper ground, spliced to the incoming neutral conductor.
The luminaire ring assembly shall be provided with the same number of 2 inch (50 mm) pipe tenons as the number of luminaires specified. Luminaire rings having more tenons than luminaires will not be approved.
If centering arms are not used to prevent the ring assembly from striking the pole during the raising or lowering of the ring assembly, a sufficient quantity of non-abrasive rollers shall be mounted on the ring interior.
The winch drum shall have a cable guide or cable follower to prevent cable buildup at the drum ends. Also a keeper shall be provided to prevent cable from fouling after cable tension has been relieved when the ring assembly is latched.
Instruction manuals supplied from the manufacturer shall be turned over to the maintaining agency after the project is completed.
Luminaires shall be equally spaced around ring as shown in HL-10.31.
With the luminaire mounting ring in its fully raised position, at the pole top, indicator flags shall be fully visible to indicate that the latches are locked.
To assure smooth operation and proper latching and unlatching of top latches of the luminaire ring assembly, the ring needs to be leveled according to manufacturer procedures. Each block requires a small slot which will enable the block to be pushed onto the hoist cable until the cable is in the center of the block. Fasteners hold the blocks in position yet allow each block to slide along the hoist cables. Blocks should be located approximately two to three feet (0.6 to 0.9 m) above the ring assembly. Carefully raise the ring until all blocks touch the latch cams. Lower the ring and accurately measure the distance from top of the ring to the bottom of each block. Adjust each hoist cable until the distance between the block and the top of the ring is equal. Raise and lower the ring several times to verify that the ring is still level.
Before excavation, foundation locations shall be checked to determine if they are in conflict with existing overhead and underground utilities. The designer should be consulted prior to relocating any support more than 10 feet (3.0 m) to resolve a conflict or if two or more adjacent supports need to be relocated.
All foundation locations shall be staked. Ohio Utility Protection Service and all utilities in the area should be allowed at least 48 hours to mark their utility locations relative to the proposed foundation.
Anchor bolt settings for light poles shall be positioned so the arm of the pole will be at the specified orientation when the pole is erected. Anchor bolts should be installed in foundations using anchor bolt setting templates. Anchor bolt projections above foundation should be checked before placing concrete.
Tops of foundations shall be finished smooth and level to enable proper plumbing of the light pole. They shall be checked for proper elevation and relationship to finish grade before placing concrete.
If a graded access drive is constructed to allow a support to be installed, consideration should be given to allowing the drive to remain for future maintenance access.
Foundations are to be placed only in undisturbed soil or compacted embankment.
If a minor cave-in should occur, the Contractor may, with the approval of the engineer, continue excavating using sleeving or casing. When bedrock is encountered, the Engineer may reduce the specified foundation depth.
If construction crews must leave the job site with a hole unfilled, it shall be covered and marked with cones, barrels or warning tape.
Prior to the placement of concrete, anchor bolts and conduit ells shall be checked for size, type, number and orientation. Reinforcing bars, tie loops and tie bars shall be of the correct size and arranged with the anchor bolts into cages according to HL-20.11 thru HL-20.21 . Cages can be wired or welded together.
Anchor bolts shall be vertical with their ends projecting the correct distance above the foundation surface in compliance with the plans. When the distance the anchor bolts project above the foundation surface is not specified, a rule of thumb is four times the bolt diameter. The anchor bolts shall be tied to the cage tie bars according to standard details.
The cage shall be supported 3 inches (75 mm) above the bottom of the excavation by a piece of concrete block or similar material and be positioned with a clearance of 3 inches (75 mm) from the excavation wall by similar blocking so that after concrete placement a full thickness cover is assured.
A template and/or frame shall be used to rigidly support the anchor bolts and conduit ells in the specified pattern during concrete placement. A form shall be oriented according to the plans to shape the foundation to a nominal depth 6 inches (150 mm) below ground line.
Water encountered in the foundation excavation shall be pumped out before concrete placement. If this is not feasible, concrete shall be placed by the tremi-tube method.
Concrete shall be placed and vibrated to eliminate voids. Care should be exercised during vibrating to avoid disturbing the anchor bolts, conduit ells and reinforcing cage. Depending on the depth of the foundation, a shoot may be needed to fill the hole with a uniform mix of concrete throughout the foundation.
Forms may be removed as soon as the concrete has hardened sufficiently so as not to be susceptible to damage.
Pull boxes are to be of the specified sizes and locations as shown on the plans. However, pull boxes in low drainage areas may be adjusted to eliminate drainage problems, with the approval of the Engineer. Pull boxes located in sidewalks, traffic islands and curbed areas close to the roadway where wide turning vehicles could drive over them may be adjusted as directed by the Engineer to alleviate the problem.
Junction boxes are installed at indicated locations. Bolts for cover plates should be lubricated with anti-seize or grease before being installed.
When possible, fuses should not be placed in junction boxes. They should be placed in pole bases.
Trench shall not deviate more than 6 inches (150 mm) from the line designated unless approved by the Engineer. When trench is cut in rocky areas, the trench shall be inspected and protruding edges or rock shall be removed or smoothed. These sharp edges can puncture duct cable when compacting backfill.
Trench backfill shall be compacted in layers not to exceed 4 inches (100 mm) in thickness. Backfill material around duct cable shall not contain pieces larger than ˝ inch (13 mm) within 2 inches (50 mm) of the duct cable. Caution tape, when specified, should be installed 6" to 8" (150 to 200 mm) below grade.
Conduit shall meet the contract requirements. Expansion or deflection fittings shall be provided.
After installation of conduit the contractor shall check each conduit run by rodding (pushing a mandrel through the empty conduit) or pulling a cleaning puck through the conduit. All empty conduit installed for future use shall contain a No. 10 AWG pull wire or equivalent. Before cable is pulled through conduit, all cut ends of metallic conduit shall be reamed to remove rough edges and a bushing shall be installed. All threaded ends shall be painted with a zinc rich paint.
All metallic conduit and other items containing conductors shall be solidly bonded to assure ground continuity.
Duct-cable shall not be installed when the temperature of the duct is below 32° F (0°C). It is permissible to install duct cable when the outdoor air temperature is actually below 32°F (0°C), but the Contractor must obtain authorization from the Engineer. The Contractor shall submit in writing his proposed method of heating and maintaining the duct to a temperature above 32° F (0°C) to assure a uniform temperature. The heating process shall begin a minimum of 24 hours prior to installation.
On days where temperatures vary widely, expansion and contraction should be considered when installing duct cable. When duct cable lengths are cut, be sure to allow for change in length due to maximum expected temperature variation where installed. The duct cable length will decrease (or increase) one foot per thousand feet (0.3 m per 300 m) for each ten degree F (5.6 degree C) decrease (or increase) in temperature.
Duct cable should extend 2" (50 mm) out of the sleeves in foundations or 3" (75 mm) out of conduits in pull boxes to allow for the duct expansion and contraction in cold and hot weather.
Due to reeling configuration, unreeling duct cable will result in cable lengths shorter than the duct length. Allow 25 feet (7.6 m) cable length shortage for each 1,000 feet (300 m) of duct to be installed. All cable shortage will occur on the starting end of each run of duct. Before installing the duct cable, calculate estimated cable shortage based on total length of run to be installed and allow this much extra duct at the starting point. Manufacturers of duct cable compensate for this allowance by supplying additional duct on the reel.
During production, the cable has been secured to the duct at the ends of each reel. Prior to burying the duct cable, remove the end caps and cut the cable free from the conduit at both ends. This will allow the duct cable to lie flat in the trench.
Duct cable shall be laid in the trench in as straight a line as possible to prevent build-up of sidewall pressures, and therefore pulling tension, in case of cable removal and re-pulling at a later time.
Care shall be taken to protect the conductor insulation when cutting the duct. At terminal points the excess duct can be cut by slipping a short piece of electrical metallic tubing (E.M.T.) inside the duct and over the conductors past the point of desired cut. Then cut around the periphery of the duct with a hacksaw or pipe cutter. The E.M.T. will protect the conductor insulation.
Repairing damaged duct cable is covered in the Section 1160 of this manual.
Terminal points of all conduit and duct cable shall be sealed promptly after installation by means of a molded plastic or rubber boot. Heat shrink tubing caps are also permitted.
All conductors terminating in pull boxes, transformer bases and switch enclosures shall be properly identified. Identification tags shall be either brass or plastic and shall indicate “CKT” followed by the designated letter of the circuit, “GND” for all ground conductors and “NEU” for all neutral conductors.
Distribution cable is defined as a single conductor, stranded copper, insulated cable used in conduits to construct lighting circuits from the control equipment at the power service to the base of light poles or the disconnect switch of towers or signs or underpass lighting.
Distribution cable shall not be spliced between terminations. Cable installed within conduit and duct-cable shall be free to be pulled back and forth for a minimum length of 2 feet (0.6 m). This test is not required when cable runs are over 500 feet (150 m) or if the runs include more than two 90 degree bends.
All cables shall be labeled in accessible enclosures (pull boxes, hand holes, transformer base, device housing, etc.). A minimum of 5 feet (1.5 m) of extra cable shall be provided for each conductor at all terminal points.
Each circuit requires one conductor and one separate neutral conductor. In non-metallic conduit, a separate ground wire should also be pulled in.
Pole and bracket cable is used to connect the distribution cable to the light fixture. It typically ranges between 10-14 AWG and meets the requirements of 625.13 and 725.02. A reduction in cable size is necessary since lighting fixtures are typically not able to accept terminations larger than #10 wire.
Single arm luminaire poles route cable up the shaft and out arm to luminaire. The luminaire is fused in the pole base. If wiring twin luminaire poles with a single cable, route cable up shaft and out arm to luminaire then directly to second luminaire. If arms are unequal in length, run cable out short arm first. If arms are equal, run cable to higher wattage luminaire first.
Improperly grounded electrical systems pose a serious threat to persons working on or near the facility. These grounding guidelines should be followed while allowing site conditions to govern the actual installation.
Grounding offers protection to personnel by eliminating dangerous or excessive voltages on the non-current-carrying metal parts of an electrical installation. Grounding also protects equipment and circuit conductors from dangerous or destructive high-magnitude ground-fault currents by providing a low-impedance (AC resistance) path back to the source for such currents.
Low-impedance ground-return paths are created when a highly conductive path is made between the electric system and ground. The typical path includes a grounding wire welded to a ground rod which is installed vertically in the earth. As the moisture content of the soil increases, the conductivity of the soil increases, thus reducing the impedance.
Without this low-impedance ground-return path, an ungrounded current-carrying conductor could fault to a grounded metal or nonmetal surface, and its overcurrent protection would not trip or open, creating a definite shock hazard to personnel as well as damage the circuit conductors and other equipment. The time-of-response characteristic of overcurrent protection is hampered or delayed by high-impedance in an inadequate ground-return path. In other words, the lower the resistance is to the ground, the faster the response of the circuit overcurrent protection when a fault condition occurs. Mathematically, this relationship is inversely proportional.
Grounding systems protect people and equipment from generated current, induced current and static electricity by creating a permanent and continuous bonding of all the non-current-carrying metal parts of a structure or other installation. ODOT standard drawings provide detail on the connection of non-current carrying metal parts to ground.
Each ground rod must be tested to measure the earth resistance with the results reported to the Engineer. Tests must be conducted before the ground rod is welded to the support or structure. The resistance must be less than 25 ohms or less than 10 ohms for tower lighting or traffic controllers. If the resistance is greater, then a second rod must be driven, temporarily connected to the first and retested. If the test results are still not acceptable, the Engineer will direct the contractor to install a ground grid as shown in the standard drawings.
The ground rod is joined to the grounding cable by an exothermic weld after successful testing. The weld and exposed cable are painted with two coats of insulting varnish. The contractor should follow manufacturers instructions with attention given to the following:
Structure grounds are installed according to the standard drawing with ground rods driven on each end of the fixed piers. When grounding cable is welded to the tops and sides of bridge beams, check that the proper exothermic weld form is being used.
Cable connection devices include connectors, connector kits, cable splicing kits, in-the-line type fuseholder kits and cable splicing kits. All devices shall be rated for minimum 600 volt service. Direct buried connections are not allowed unless directed by the Engineer.
Connectors applied to the conductor by means of a compression tool shall be made of high-strength copper alloy and sized for the conductors used.
Cable connections using connector kits are only permitted in handholes or transformer bases of light poles, and in junction boxes within bridge and median barrier structures.
Connector kits used in pole wiring shall be of a quick disconnect type.
When assembling connector kits, no sharp bends in cables shall be permitted within 8 inches (200 mm) of the connector kit entrance end.
Provide sufficient slack in all cables to permit bringing connector kits outside of pole base through handhole of pole or door in transformer base.
Kits should be fully sealed to prevent the infiltration of water. Lubricants, provided with the kit, shall be used so the rubber boots set together snuggly to keep water away from the conductors.
An approved poured epoxy waterproof splice kit or heat-shrinkable sleeve or wraparound pad coated with a heat-activated self-encapsulating adhesive shall be used.
Epoxy splice kits are easily damaged by freezing temperatures encountered prior to mixing. Damaged epoxy components may sometimes be recognized if either of the components have turned or are streaked milky white.
Connections of the conductor(s) shall be made by a copper compression connector.
The plastic mold body ends shall fit slightly loose around the cable when the mold is snapped together. Check mold to determine that the splice is centered and that both seams of the mold are completely snapped together. Ends of the mold are taped to seal around cable.
Resin is mixed and poured according to manufacturer instructions. When the resin has solidified and cooled the splice kit shall be inspected to determine that no epoxy resin has leaked out and that there are no visible voids in the resin.
All kits shall be designed to fit most commonly available crimped connectors. Kits shall employ a heavy-wall, heat-shrinkable outer jacketing sleeve with mastic sealing to ensure a positive moisture-proof seal.
Following appropriate cable preparation, slide the shrinkable tubing to one side and install the copper compression connector. Some heat-shrinkable splice kits use a wrap-around sleeve in lieu of tubing. Ensure stress relief compound or mastic insulation strip is applied around the connector.
Shrink tubing is heated by using the yellow tip of a torch flame or a heat gun. Apply heat uniformly around the tubing, directing heat from end to end using a back and forth painting motion. Heat is applied until the adhesive extrudes from the ends. Some tubing has an indicator paint which will change from green to black indicating that enough heat has been applied.
Follow the manufacturer’s recommendation for wire size when connecting the distribution cable to the cable feeding the device. Ensure that the cable is rated for the correct voltage.
Power services should be installed to conform with local utility requirements as well as the contract documents.
Before installation of the service pole, an inspection shall be made at each proposed control center location, to determine the accessibility to the supplying utility company and for future maintenance. Control center locations, if possible, should never be located below mainline grade where possible drainage from pull boxes, etc., could flood the enclosures by hydrostatic action.
Main switch lugs shall be of an adequate size to accommodate the service entrance cable. No individual strands of the incoming conductor shall be cut to accommodate an undersized lug. This also applies to the outgoing circuit cable and neutral bar (grounding bar) lugs.
The photocell shall face north unless the Engineer directs another orientation to avoid interference from an artificial light source.
The size of the conduit shall be as indicated, unless otherwise called for by plan. It shall be adequately secured. There shall be no cracks, scratches or dents.
When a meter is required by the plan, the Contractor shall install the meter housing. The meter opening shall be closed with a blanking cover until the meter is installed.
There shall be no cracks, scratches or dents on the enclosure. All conduits attached to the enclosure shall be tightly secured and, where used, all locknuts shall be tight. Except for a 1/4" (6.4 mm) weep hole on bottom of enclosure housing, all conduit attachments shall be water-proof.
With the lock removed from the disconnect handle, and the disconnect handle placed in “ON”, the enclosure door shall be free to open.
With the door open there shall be no loose wires (wires disconnected), dirt, moisture or other matter. All wires shall be connected securely. There shall be no exposed bare wires. All major devices shall be tightly secured. Each fuse clip shall contain a cartridge fuse sized by plan. All wire insulation shall be free of cracks, cuts, scratches and dirt. All wires routed together between devices shall be bound and lay against the back of the enclosure. No wires shall touch or interfere with any device or the door.
There shall be a lightning arrester on the incoming service and a grounding wire from the lightning arrester to a ground rod.
A grounding conductor will normally be connected to the neutral bar and said bar will normally not be insulated from the equipment enclosure.
The grounding wire shall be protected by a wood molding for a height of 2 feet (0.6 m) above the finished grade.
Poles shall be 35 feet (10.7 m) minimum length and be Class 4 or heavier.
In accordance with 625.19, the lighting shall meet the requirements of the following tests and shall be performed by the Contractor: Ground Rod Test, Cable Continuity Test, Cable Insulation Test or High Voltage Test, 10 Day Performance Test and Luminaire Lowering Device Test.
The test results shall be witnessed by the Engineer and a record of the test results shall be documented.
Contractor shall submit a written certification that the testing equipment was last calibrated by a certified testing agency not more than 60 days prior to the date the tests are performed. This certification along with certified copies of the test results shall be furnished to the Engineer.
During the 10 day performance test, a night inspection shall be performed by the Contractor and final adjustments made to level all luminaires to the satisfaction of the Engineer. The adjustments are required to eliminate excessive brightness and glare, and to obtain optimum brightness and uniformity of illumination.
Following the successful completion of a 10 day performance test and after there has been a partial or final acceptance of the project, the Contractor shall turn over to the Engineer all manuals, diagrams, instructions, guarantees and related material. The Engineer will transfer the material to the maintaining agency. For State maintained lighting, the material should be given to the District Roadway Services Manager.
Immediately after final acceptance of the project, the Engineer shall notify the maintaining agency as to the exact time and date that maintenance of the lighting facility will become that agency’s responsibility.
All ground rods shall be tested by the Contractor for earth resistance to ground. Testing is to be in accordance with 625.19(B) except measurement need not be made immediately after installation. Testing shall be performed before the ground wire is attached to equipment being grounded.
The quality of a ground rod installation varies greatly depending on the characteristics of the earth surrounding the rod. Clay or mud provides the best ground connection since they are dense materials and contain sufficient moisture and metallic salts to make them conductive. Sand or gravel bearing earth is less conductive.
To measure the earth resistance of a ground rod follow test equipment manufacturer’s procedure.
When the earth resistance exceeds 10 ohms for tower lightning ground rods and 25 ohms for all other ground rods, the installation is unsatisfactory and the Contractor is required to proceed as specified in 625.09.
It should be impressed to all test personnel that a lethal potential can exist between the station ground and a remote ground if a system fault involving the station ground occurs while ground rod tests are being made.
Safety precautions while making these tests by wearing rubber gloves and other protective devices is recommended. At no time should the hands or other parts of the body be allowed to complete a path between points of possible high potential difference.
Before the cable insulation test, high voltage tests or performance tests, the Contractor shall perform a continuity test using a volt-ohm meter, or other approved instrument. Continuity tests shall be conducted on all lighting circuits with the electrical loads, power sources and all grounds disconnected.
Each circuit shall be temporarily jumped at its termination and measured for continuity to assure that no open circuits exist.
All conductors shall also be measured against every other conductor and ground to assure that no short circuits, cross circuits or other improper connections exist. No voltage shall exist between one conductor and another conductor, including grounds.
Measure for continuity to assure that no open circuits exist.
Turn function selector to resistance . A resistance of nearly zero ohms should be indicated. If a high resistance is found, the circuit is unacceptable.
Each circuit cable shall be tested by the Contractor for insulation resistance measured to ground. A listing of the resistance reading for each conductor shall be included in the test results furnished to the Engineer in accordance with 625.19(D).
Cable and wire insulation can be faulty, but the imperfections can be easily overlooked, leading to eventual electrical failure of the wiring. Weakening of insulation properties may be caused by poor storage conditions and stress due to rough handling during installation. Dirt is especially troublesome, since it is an electrical conductor and can penetrate small cracks in the insulation.
Cable insulation resistance can be tested by first disconnecting the ends of each conductor to be tested so there is no chance at any voltage being present and to prevent damage to any connected equipment. especially at the control center. The conductor under test is then connected to one terminal of the Megger Tester. A ground connection is then made from the ground terminal of the Megger Tester to an established ground such as the grounded neutral of the circuit.
The meter pointer of the megger instrument (or equivalent indication) shall be adjusted to zero and the test switch activated. Test duration shall be as recommended by the instrument manufacturer.
The insulation resistance measured to ground for each conductor shall not to be less than 10 megohms. Cable or wire not meeting this reading shall be repaired or replaced.
After completion of the cable insulation test, all control center wiring shall be connected in accordance with the wiring diagram. The Contractor is to demonstrate to the satisfaction of the Engineer that all circuits are continuous and operating correctly, with no shorts, crosses or unintentional grounds.
Cable Insulation Tests are not required if the project plan requires a High Voltage Test.
When testing with a Megger Tester, remember that there is a high voltage across the terminals when testing in the megohm range.
The main disconnect device shall be locked in the OFF position. Pole and bracket cables shall be disconnected at each light pole by unplugging the connector kits. Light towers, sign lights, underpass lights and other devices fed by the circuit shall be disconnected by opening the disconnect switch.
The test shall be performed on each insulated conductor of the circuit at the control center and the results recorded and plotted.
With voltage at 0, attach high-voltage lead to the bare copper conductor to be tested and the metered return lead to insulation of conductor being tested. It may be necessary to wrap a piece of conductive tape or soft copper collar around the outer insulation where the metered lead connection is made, if the metered return clip cannot be properly attached, because of the thickness of the insulation.
It should be noted that there are three (3) binding posts on Hypot Test Equipment that the metered return wire can be connected to. The metered return should always be connected to the metered binding post (Red). The cable insulation test can then be performed no matter which position the ground switch on the equipment is in. If the metered return is connected to the ground binding post (Silver) then the ground switch must be in the metered position. Meters on the instrument will not operate if switch is in the bypass position. Should metered return wire be attached to the bypass binding post (Black) then no readings can be obtained, because meters on the equipment will not operate, no matter which position the ground switch is in.
For safety reasons always ground the Hypot Test Equipment by attaching a ground wire to the safety ground on the equipment and then to an established earth ground.
Determine and record temperature of the air and relative humidity at the time of testing.
Faulty conductors and/or connections shall be replaced and the circuit retested until satisfactory test results are obtained.
The test results shall be considered as satisfactory if both of the following conditions are met:
Faulty cable is indicated if::
Before acceptance of the lighting system, the Contractor shall furnish all personnel and equipment required to successfully operate the systems for 10 consecutive days without major malfunction or failure.
At least 7 days prior to the beginning of the performance test, the Contractor shall notify the Engineer of the starting date.
The Contractor shall arrange with the utility supplying the power for purchase of the energy to conduct the performance test. All costs of personnel, equipment, electrical energy and incidentals required for performing the test shall be included in the contract unit prices for the respective items tested.
Minor failures such as lamps or ballasts shall be immediately replaced or repaired and will not cause restart of the test.
A major malfunction or failure such as a control center etc., will cause termination of the test, and after replacement or repairing of the malfunctioned or failed equipment, the beginning of a new 10 day test.
Items which have been repaired or which are replacements shall be monitored by the Contractor for a period of ten days to provide assurance of their reliability.
The complete test results shall be furnished to the Engineer. The Contractor shall record the beginning and ending of the test and the method and date of the correction of each fault.
The Engineer shall record the following events in the project diary: The date of the beginning of the 10 day performance test, a day by day record of faults as they occur during the test, and the date of the successful completion of the performance test.
625-17.6
Luminaire Lowering Device Test
During the 10-day performance test the Contractor shall demonstrate the workability of the luminaire lowering device by lowering and raising the luminaire ring assembly on each tower on two separate occasions.
Check to determine that latching and unlatching of the ring assembly is smooth and no abrupt jerking occurs.
The torque limiter on the winch drive motor shall be tested when the ring assembly is raised until the torque limiter slips at the top of the ring travel. Field adjustment of the torque limiter setting shall not be attempted. If the limiter does not properly function, the complete drive assembly shall be returned to the factory for authorized repair or replacement.
To prevent future cable problems, it will be necessary to check, by using a good flashlight or other hi-power light source, the transition or clevis plate, hoisting cables and power cord to determine if they have rotated or twisted. This is due to “Constructional Stretch” of the new wire cables which can be caused initially with the first raising of the ring assembly with the full weight of the luminaires. The twisting can be removed by hand rotation of the transition or clevis plate.