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Part Five. Safety and Maintenance Procedures

CHAPTER 13

Safety

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This chapter emphasizes safety rules and principles in electrical wiring and repair work that will minimize or eliminate the hazards and dangers in electrical wiring. The practices described in this manual conform to the rules of applicable safety codes and regulations that are covered in detail in TM 5-682 and follow guidelines of the National Electrical Code (NEC). The NEC governs all electrical construction. Deviations from these practices resulting from emergency expedients must be corrected at the earliest possible time after such an emergency ceases to exist. Military personnel must never take safety for granted but should keep it in mind and practice it at all times. Strict observance and enforcement of the following procedures will minimize both the number of accidents and the costs of installing, operating, and maintaining the systems.

Section I. Basic Safety Rules

GENERAL WORKING PRACTICES

KEEPING THE JOB AREA CLEAN

Make every attempt to keep the work area in the field or the electrical repair shop free of materials and debris. Grease, oil, water, and similar material on the floor create slipping hazards that can cause serious injuries. In addition, loose fittings, wire and conduit ends, and other debris stored or thrown at random on the floor in or around the job site create tripping hazards that can cause personal injuries. Developing good housekeeping in and around the work area establishes good work habits that are carried over into wiring installation.

WARNING FELLOW WORKERS

Warn fellow workers who get into dangerous positions. These warnings protect not only the person warned but also the rest of the crew. Some members of a crew are less experienced than others and may not realize the danger of their working positions.

ACTING RECKLESSLY

Avoid horseplay, wrestling, scuffling, practical jokes, and unnecessary conversation during duty hours. Electrical work is not dangerous when you take proper care, but it may become dangerous if your attention is distracted.

WEARING CLOTHING AND JEWELRY

Apparel is an important safety consideration for persons working on or near electrical equipment. Everyone must follow the practices below:

• Never wear shirts, trousers, overalls, or any items of clothing that have zippers or other metal fasteners unless the fastener is covered.
• Always roll shirt sleeves down.
• Never wear loose, flapping clothing or flammable articles such as celluloid cap visors.
• Never wear shoes with thin soles, heel plates, or hobnails. Wear high-cut shoes with sewed soles when possible.
• Always wear suitable gloves and clothing and approved goggles or head shields when operating welding equipment.
• Wear leather gloves (linemen and groundmen).
• Remove all jewelry before starting work. Never wear rings, metal wrist bands, or watch chains.
• Inspect all personal gear (climbing gear, hard hats, and rubber gloves) before use.

REPORTING UNUSUAL CONDITIONS

Promptly report to the installation engineer any unusual conditions in stations, substations, or underground and overhead systems that may affect the continuity of service or endanger life or property. Take necessary protective steps immediately, even if stopping other work is necessary.

PREVENTING FIRES

Observe the following safety rules:

• Do not obstruct approaches to fire-fighting apparatus by blocking driveways, doors, or aisles.
• Deposit all flammable waste materials in waste cans with self-closing covers. Remove the materials at the end of the day.
• Keep flammable liquids in approved safety cans with self-closing covers. Do not store more than 1 gallon in each safety can inside a building.
• Never use flammable liquids to start a fire in a salamander or a rubbish pile.
• Do not use gasoline as a cleaning agent; use a low-hazard solvent, preferably nonflammable.
• Never use a gasoline furnace or a blowtorch where flammable vapors are present.
• Train all personnel in the proper selection and use of a fire extinguisher that is appropriate for different classes of fires.
  • Class A. Class A fires include ordinary combustible material such as paper, wood, and textiles. Use a water-type extinguisher.
    

  • Class B. Class B fires include flammable liquids such as oil or gasoline. Use a foam, carbon-tetrachloride or carbon-dioxide extinguisher; dry compound; or sand.
  • Class C. Class C fires are in electrical equipment. Use a carbon-tetrachloride or carbon-dioxide extinguisher.
• Notify the fire department immediately whenever a fire extinguisher has been used so that it can be recharged or replaced.

USING FIRST AID AND RESUSCITATION

Observe the following rules in the installation electrical shop (see FM 21-11 for additional information):

• Ensure that the electrical shop and each of its trucks have adequately stocked first-aid kits.
• Treat minor cuts and injuries on the job; ensure that serious cuts and injuries receive appropriate medical attention.
• Report all accidents to the foreman.
• Train personnel thoroughly in prone-pressure and pole-top methods of applying artificial respiration. The electrical foreman in each shop should schedule practice in artificial respiration once a month for every member of the electrical section.

OPERATIONAL SAFETY PRACTICES

WIRE STRIPPING

One of the most common electrical operations is wire stripping. This can be done with a tool designed for this purpose or an electrician's knife. When using a knife, ensure that the force of cutting is directed away from your body and other personnel.

SOLDERING

Observe the following precautions when soldering:

• Keep furnaces away from manhole openings so that hot metal or compound cannot spill into the manhole if the furnace is overturned.
• Never put a cold or wet ladle or other objects in molter solder or in hot compound because spattering results.
• Attach the pot with a hook and a steady line to prevent excessive swinging when raising or lowering molter solder or hot compound on a hand line. Ensure that persons on the ground or in a manhole stand clear.
• Always work from above or the side when soldering to prevent burns from splashing solder.
• Wear goggles when soldering large joints and tinning lugs or T connectors.

CIRCUIT TESTING

Never attempt to modify or repair an existing circuit until you have tested the circuit following the procedures in Chapter 14. Do not test a circuit with your fingers or with any tools other than a test lamp or a volt-meter.

SWITCHING AND TAGGING

Notifying Serving Utility

The installation engineer must notify the system operator of the serving utility before any switching operations are performed that may affect the serving utility's system. This is necessary so the serving utility can provide for a substantial power increase or decrease or can carry out prearranged emergency measures in case circuit breakers are tripped out.

Switching Operation

The electrical foreman must perform the switching operation with great care. He must see that each worker knows exactly which equipment is energized before starting work.

Tagging Procedure

When any line, feeder circuit, or apparatus is taken out of service for inspection, repair, or maintenance work, a tag or marker must be placed on all main or control switches. Ensure that the equipment remains de-energized until it is released by the individual who initially removed it from service. The tag or marker must contain the following information:

• The words "DANGER. Do not remove this tag or energize the circuit."
• The name of the individual removing the item from service.
• The date and hour the tag was placed.

A sample tag is shown in Figure 13-1. Tags can be purchased from sign sources or fabricated from a manila folder or similar material.

Once all the work is complete, the individual who initially installed the tag must remove the tag and restore service.

TOOL AND EQUIPMENT USAGE

Maintain tools and equipment in good operating condition and replace them when broken. For both safety and good workmanship practices, never use improperly operating equipment in wiring practice. Inspect tool handles periodically for correct positioning with reference to their working surface. Ensure that handles are tight and insulate them against shock hazard when possible. Keep drills, chisels, saws, and similar cutting tools and equipment sharp. Cover workbench surfaces and surrounding floor areas with rubber insulation.

HAND TOOLS

The general safety principles for electrical tools also apply to personal safety in electrical installation. Insulated handles are an added safety precaution only and should not be relied on for full shock immunity. The following safety precautions apply for tools and equipment used by electrical workers:

• Select the right tool for the job. Avoid using make-shift tools.
• Keep all keen-edge tools sharp because they are safer sharp than dull. Store them properly when not in use.
• Ensure that skinning knives do not have sharp points and that the metal shank of the knife does not extend through the handle.
• Ensure that work is substantially an-chored when using a draw knife.
• Ensure that pipe-wrench jaws are sharp so they cannot slip.
• Use the right-size wrench for the job. Face the jaws of an adjustable wrench in the direction of pull.
• Avoid using a hammer on highly tempered tools such as drills and files because chips may fly into your face and hands.
• Tape the handles of pliers, especially the ends, to lessen the likelihood of dropping them.
• Never use tools that have cracked or broken handles, no handles, or cracked or broken heads. Replace damaged tools with new ones.
• Never use a wrench on a running motor.
• Never use any tool in such a way that your hands or body can be injured if the tool slips.
• Use flashlights in basements, vaults, manholes, or other dark places when light is needed. Never carry open flames into these places because of the danger of explosion or fire.

GOGGLES

Wash goggles thoroughly with soap and water before somebody else wears them. You must wear goggles if you are--

• Tinning or soldering lugs or large joints.
• Chipping, breaking, or drilling concrete, brick, stone, or other materials where chips are likely to fly.
• Doing any work, such as tree trimming, that is likely to cause flying chips or particles.
• Installing or removing fuses or jumpers from live distribution busses. Use goggles with approved colored lenses.
• Welding. Only use goggles that meet the specifications of the American Standards Association and are approved for electric arc work. Goggles used for acetylene welding cannot be used for electric arc welding.

SCAFFOLDS AND LADDERS

SCAFFOLDS

When the wiring location is inaccessible from normal work areas and the installation is large or complex, use scaffolds rather than ladders for overhead or elevated work platforms. All scaffolds should be sturdy, well-built, securely anchored, and cross-braced. The scaffold planking should be free of knots, checks, and cross-grained sections. Planks used for scaffolding should be load-tested periodically with up to three times their workload. Do not use them if failure or weakness shows up in the test.

LADDERS

All ladders used to reach the work area must be in good condition, constructed safely, and unpainted. When using a ladder, anchor it to the building with a rope or a chain or place it against a projection on the supporting surface. If you cannot secure it in either of these ways, have an assistant stand at the base of the ladder. The distance between the base of the ladder and the vertical surface against which it is supported should be approximately one-quarter the length of the ladder.

Using Ladders

• Inspect ladders at regular and frequent intervals.
• Do not paint wooden ladders. Remove excessive dirt that might conceal defects.
• Use a safety strap (Figure 13-2) when doing a job that requires using both hands.
  
• Do not use a ladder in a strong wind.
• Do not use a ladder for a guy, brace, skid, horizontal scaffold member, or any other purpose other than that for which it is intended.
• Never use a metal ladder when working on electrical equipment.
• Do not use makeshift ladders made by fastening cleats across a single rail.
• Ensure that all straight ladders and extension ladders have approved antislip devices or are otherwise safely secured.
• Work with another person when using an extension ladder near heavy traffic. Have the person stand at the bottom of the ladder and hold a red flag in daylight or a light in darkness.
• Do not reach out from the ladder in any direction; move the ladder as the work requires.

Placing Ladders

• Never place ladders on a slanting or slippery footing unless they are securely tied or held in place.
• Ensure that stepladders are fully opened before using them.
• Ensure that the distance from the foot of the ladder to the wall is one-fourth the length of the ladder.
• Ensure that extended extension ladders are in a standing position and that hooks are securely caught on rungs so that the ladder cannot telescope when jarred.
• Do not place ladder jacks above the third rung from the top of a 24- or 36-foot extension ladder or above the fourth rung from the top of a 46-foot extension ladder. This ensures that the ladders have the proper strength and stiffness.

Ascending and Descending Ladders

• Always face the ladder when ascending or descending.
• Allow only one person to ascend or descend at a time.
• Do not ascend or descend without the free use of both hands.
• Do not ascend higher than the third rung from the top on straight or extension ladders; do not ascend higher than the second rung from the top on stepladders.
• Never slide down a ladder.

Section II. Exterior Safety Rules

TOOL AND EQUIPMENT USAGE

The following safety rules apply when handling tools or equipment:

When in the work area--

• Do not throw tools or materials up or down to workers on different levels. Use hand lines to raise or lower them individually, in canvas tool bags, or in buckets.
• Stand clear when tools or materials are raised or lowered; avoid coming directly under the load until it is properly placed and secured.
• Prevent tools and materials that are raised or lowered from coming in contact with wires or other equipment.
• Avoid working at the base of a structure or a pole while others are working on it except in an emergency.

When handling materials--

• Pick up insulators by the top to avoid cutting your rubber gloves or hands on the petticoat. Do not screw down insulators too tightly because the top may break off and cut your gloves or hands.
• Be very careful when lifting heavy material by hand. Bend your knees and keep your back straight. Use mechanical devices to lift heavy weights, when possible, or obtain enough help to do the job easily.
• Use ropes or tackle to control the motion when moving heavy loads on inclines. Ensure that workers do not stand on the downhill side.
• Lift heavy material or equipment with an approved hoisting apparatus that is capable of carrying the load safely. Rope off areas immediately below the load. Display warning signs and guard the area properly.
• Lash or securely tie transformers and oil drums to prevent sliding or tipping while being transported.

ROPE

Take the following precautions when using rope:

• Ensure that any rope used near live conductors or equipment is free of metal strands.
• Turn in the rope for replacement when the strands become frayed.
• Keep the rope clean so that sharp particles of solder or other substances cannot cut your hands or rubber gloves.
• Keep your hands at a safe distance when taking hold of a rope passing through a block.
• Do not place tape, string, or marlin cord on a rope to repair defects.
• Never loop a rope over your hand or arm because it could be a tripping hazard while climbing.
• Never leave uncoiled wire, rope, or other material unguarded on streets, roadways, or alleys because of the potential tripping hazard.
• Never hang safety lines, ropes, or wires from a pole because they could interfere with passing traffic.

BODY BELTS AND SAFETY STRAPS

The foreman should inspect all body belts and safety straps during regular tool inspections to determine the condition of all parts. If he finds or suspects the following faulty conditions, straps or belts must be repaired or replaced at once (see TM 9-243 for further guidance).

• The leather is worn or crushed. Ensure that the leather loops holding the D-rings are not worn or crushed enough at the edges to weaken the leather or cause it to tear. If the straps are otherwise sound, you can use them until they are not less than 1/8 inch thick in any portion other than the doubled part of the strap. In this portion, the leather may wear slightly less than 1/8 inch because a double portion is approximately twice as strong as a single portion.
• The leather is hard and dry.
• The leather is burnt. Burnt leather is dry on the outside. Bending at the burn spot cracks the leather, and small pieces between the cracks may be removed easily with your fingernail.
• The leather has cracks, cuts, nicks, or tears (particularly across or on the edges of the strap) that tend to affect its strength.
• Rivets (particularly those in the loops holding the D-rings) are loose or broken.
• The pouch for holding pliers is broken.
• The buckle is broken or defective.
• The snaps are broken or defective.
• The steel-reinforcing strap is broken or badly worn.
• The buckle hole is torn or excessively enlarged. The tongue should work freely without side play and close securely under the spring tension.
• The grain on the straps is worn. If the smooth side of the leather is worn so that fibers are plainly visible and a red stitching becomes visible, the strap should be cut up and thrown away.

RUBBER PROTECTIVE EQUIPMENT

Follow the safety rules below for inspection, use, and care of rubber protective equipment:

Inspection

• Before starting work on or near live conductors or equipment carrying between 300 and 5,000 volts, ensure that each worker personally tests his rubber gloves. Make a thorough visual inspection for holes and thin spots. When rubber gloves or other protective equipment is believed to be defective, tag it and turn it in for replacement immediately.
• In addition to the daily visual check, give rubber gloves a semiannual electrical test. Give other rubber protective equipment an electrical test annually. Make arrangements with the servicing utility to conduct these tests.

Use

• Wear rubber gloves when working on or within reach of energized conductors or equipment operating at voltages between 300 and 5,000 volts.
• Wear leather protective gloves over rubber gloves to protect them from mechanical damage. Pin holes or thin spots caused by using gloves without protectors may be hazardous to workers.
• Use approved live-line tools without using rubber gloves for work on lines that are energized at more than 5,000 volts.
• Wear rubber gloves while cutting supposedly dead cables and while testing supposedly burned-out transformers on both primary and secondary sides.
• Do not remove rubber gloves until you are entirely out of reach of energized equipment.
• Do not work with the gauntlet of rubber gloves rolled down.
• Wear rubber gloves if you are tending reels when wire is being strung or removed near other wires energized between 300 and 5,000 volts, and if you are working near someone who is near conductors or equipment energized at voltages between 300 and 5,000 volts.
• Use a hand line to raise or lower all rubber protective equipment in a canvas tool bag or a bucket (Figure 13-3).
  

Care

Rubber gloves should be issued to each lineman, and he will be the only user of this personal item. It is his responsibility to take the following safety precautions:

• Store rubber gloves in a canvas bag when they are not in use.
• Give rubber gloves an air test each day before starting work and each time you encounter an object that may have damaged the gloves.
• Wash gloves with warm water and mild detergent.
• Be careful when applying or removing rubber protective equipment. Do not work over energized conductors or equipment or get in a position that may cause you to come in contact with them.
• Dry rubber protective equipment before putting it away if possible. If you must put it away wet, dry it as soon as possible to prevent deterioration.
• Do not carry rubber protective equipment in compartments on trucks or in tool bags with tools or other equipment.
• Always roll, never fold, rubber blankets when putting them away.
• Put rubber hoods and hoses flat in truck compartments.

GAFFS

Take the following precautions to ensure that gaffs are the proper length and sharpness:

• Never sharpen gaffs on the underside, except to make the shoulder, because it changes the angle to which they are set and renders the climber unsafe.
• Make the underside straight when removing metal to make the shoulder, because a wounded surface may cause the gaff to break out of the pole when climbing.
• Do not sharpen the gaff with a grindstone or an emery wheel.
• Put the climber (Figure 13-4) in a vise with the gaff uppermost.
  
• Sharpen the gaff on the two outer surfaces with a file. Take long strokes from the heel to the point of the gaff. Remove only enough material to make a good point.
• Never sharpen the gaff to a needlepoint. Leave a shoulder about 1/8 inch back from the point. The distance across the gaff at the shoulder should be about 5/32 inch. Sharpening the gaff in this manner prevents the point from sinking too far into the pole.

CLIMBERS

Take the following precautions when using climbers:

• Do not use climbers after gaffs are worn shorter than 1 1/4 inches on the underside.
• Remove climbers when moving from job to job or when working on the ground.
• Remove climbers before working on a ladder, standing on a rubber blanket, or riding in a vehicle.

HOT-LINE TOOLS

The following safety rules govern work with hot-line tools:

• Do not perform hot-line work when rain or snow is threatening or when heavy dew, fog, or other excessive moisture is present. Exceptions to this rule are when conducting switching operations, fusing, or clearing damaged equipment that presents a hazard to the public or to troops.
• Stay alert. If rain or snow starts to fall or an electrical storm appears while a job is in progress, complete the work as quickly as possible to allow safe, temporary operation of the line until precipitation or lightning ceases. Judgment of safe weather conditions for hot-line work is the foreman's responsibility.
• Perform hot-line work during daylight if possible. In emergency situations, you may work under artificial light if all conductors and equipment being worked on are made clearly visible.
• Do not wear rubber gloves with hot-line tools because they make detection of brush discharges impossible.
• Avoid holding outer braces or other metal attachments.
• Avoid unnecessary conversation. This distracts the attention of linemen from work, causes confusion, and adds unnecessary hazards.
• Maintain close cooperation among everyone on the job.
• Treat wooden pole structures the same as steel towers. Do not depend on the insulating value of the wood.
• Be careful with distribution primaries. When they are located on the same pole with high-tension lines, cover them with rubber protective equipment before climbing through or working above them.
• Do not change your position on the pole without first looking around and informing others.
• Never use your hands to hold a live line clear of a lineman on a pole. Secure the line with live-line tools and lock it in a clamp.
• Stay below the live wire when moving it until it is thoroughly secured in a safe working position.
• Take special precautions on poles having guy lines.
• Do not use a rope on conductors carrying more than 5,000 volts unless the rope is insulated from the conductor with an insulated tension link stick.

VEHICLES

Follow the safety rules below when operating or working with vehicles:

• Never hang coils of wire or rope outside a truck because they could easily catch on passing vehicles.
• Take care when using materials or tools that extend 4 feet or more behind a truck body. Attach a danger flag near the end of the projection during the day, and use a red lantern at night.
• Provide a red lantern or taillight with any equipment that is being pulled by a truck at night.

EXTERIOR WORKING PRACTICES

EXCAVATION

• Place necessary barriers, red flags, and warning signs to protect traffic and guard workers when making excavations in or near highways. Place red lights or flares at night to give ample warning to approaching traffic.
• Place signs between 100 and 300 feet from the outside edge of the work area. Follow shoring and bracing procedures defined in Engineer Manual (EM) 385-1-1.
• Display a MEN AT WORK sign or another suitable warning when opening manholes briefly in daytime for inspections, tests, troubleshooting, and so forth.
• Notify the person in charge when you find obstructions in digging. This notification will help avoid accidental contact with live cables and damage to property.

MANHOLES

Follow the rules below when working at manholes:

• Make a gas check before opening a manhole cover, if possible.
• Remove or replace manhole covers with cover hooks or other approved tools.
• Do not enter a manhole until after a gas check has been made. Use a mine safety lamp or a chemical detector to make checks several times throughout the day. Carefully check manholes near gasoline storage tanks. If gas exists, ventilate the manhole with a power blower.
• Use only gasproof lights in a manhole if you suspect explosive gases.
• Assign someone with a red flag or lantern to warn pedestrians and vehicular traffic when a manhole is opened during daylight. At night, mark open manholes as shown in Figure 13-5.
  
• Ensure the safety of workers in manholes if they cannot be seen by fellow workers on the surface, even if interrupting other duties is necessary.

POTHEADS

• Open the neutral pothead last and close it first when opening and closing circuits with potheads.
• Do not stand on a concrete floor or on the ground while operating potheads in manholes or vaults. Instead, use an insulated stool, a crossarm, or other dry lumber. Cover all grounded framework safely. In locations containing water, take all possible precautions.
• Keep your body clear of all grounded equipment when working on or near potheads.

POLES

Working On

• Warn persons nearby when moving a pole by hand, with a pole cart, or with the truck derrick. Station someone with a red flag to warn or stop traffic as necessary.
• Report poles to the foreman that appear unsafe for climbing so that they can be properly braced or guyed. Take special care with untreated pine poles because they deteriorate rapidly.
• Do not remove wires or supporting guy lines from a pole until the condition of the butt has been checked.
• Support unsound poles with pike poles or guy lines before starting excavation or removing wires.
• Remove all the equipment around the pole being removed before starting excavation.
• Climb to your working position by the safest path and take the safest position possible, keeping all parts of your body clear of grounded or live portions of equipment.
• Do not use pins, braces, or guy lines as handholds.
• Never carry any tools or material in your hands when climbing.
• Watch for hazardous and dangerous conditions such as rusted hardware and defective guy lines, braces, and arms. Repair such conditions immediately.
• When more than one person is ascending or descending, ensure that the first person reaches his working position or the ground before the second person starts to ascend or descend.

Climbing

• Take care when climbing past another worker so you do not damage his safety strap with your gaffs.
• Ensure that your safety strap does not catch on the pole steps when climbing. When wearing a body belt and a safety strap, snap both ends of the strap into same D-ring when you are not in the working position.
• Never put both snaps of your safety strap in one D-ring while in the working position on a pole. Ensure that one snap is fastened in each D-ring.
• Avoid pressure on the tongue snap when leaning against arms, pins, braces, and wires to prevent the safety snap from becoming disengaged from the D-ring.

Section III. Electrical Safety Rules

VOLTAGE

LOW

Electricians may work on energized conductors and equipment operating at 300 volts or less if all adjacent energized or grounded conductors and equipment are covered with insulating material or approved rubber protective equipment. Follow the safety precautions below when working on energized conductors and equipment operating at 300 volts or less:

• Tape or cover all bare or exposed places on one conductor before exposing another one.
• Open switches and remove fuses when working on building wiring, motors, belting, shafting, blowers, or other machinery (including shop machine tools). Attach hold cards to the switches.
• Do not touch steam or water pipes when handling portable electric tools or light cords.
• Never leave joints or loose ends of wire untaped unless otherwise protected.
• Never turn on current in a building where a fire has occurred and electric wiring or apparatus has been affected until a careful safety inspection is made by the fire department or a safety inspector. Parts damaged by heat, water, or extinguisher fluid may short-circuit and rekindle the fire.

INTERMEDIATE

De-energize ground lines and equipment operating between 300 and 5,000 volts before starting any work. The only exception to this is when working on overhead lines. When working on them, wear rubber gloves. All work on energized lines, except in an emergency, is executed only when directed by a work order.

Checking Energized Conductors

Consider conductors and equipment normally operating between 300 and 5,000 volts to be energized until positively proved otherwise. When you cannot establish positive proof by a visual check, use an approved voltage detector. Before using the detector, you must check it on a conductor that is known to be energized and note a positive indication. You must repeat this check on a known live conductor after making the test on a dead conductor. If rechecking the voltage detector on a live conductor is impossible, use two voltage detectors, one as a check against the other.

Insulation

When working within reach of conductors or equipment operating between 300 and 5,000 volts, all energized and grounded conductors or equipment must be covered with rubber line hose, insulator hoods, line protectors (pigs), or blankets or must be isolated with suitable barriers. If you change your position, cover or barricade any energized or grounded conductors and equipment coming within reach before starting new work.

Use the following safety precautions when working on equipment and conductors operating at 300 to 5,000 volts:

• De-energize by opening sectionalizing switches and effectively ground the section of line being worked on.
• Treat line wires being installed on poles as if they were energized when those poles are already carrying energized conductors. Use rope to pull line wires into position.
• Remove wire from the underside of reels.
• Ground the truck when using a pay-out reel to string wires near energized wires of this classification.
• Take care when stringing wire near other wires energized with 300 to 5,000 volts. Ensure that the worker tending the pay-out reel wears rubber gloves and does not allow any part of his body to come in contact with the wire being strung. Whenever possible, see that he stands on dry lumber or other insulating materials.
• Apply the brake to the rim of the pay-out reel on the side opposite the direction the wire is being pulled. A crossarm or sidearm may be used as a brake.
• Hold the loose ends of jumpers in the clear, or have someone at each end hold them if necessary.
• Keep the tie wire coiled during installation or removal to prevent accidental contact with an energized conductor.
• Have a worker test for voltage before removing a primary or secondary wire. The wire should be rechecked by the foreman to ensure that it is dead.
• Treat the spans of wire to be removed as energized. Attach a rope to each end and lower the spans one at a time.
• Make all possible connections to dead wires and equipment with only the final connection made to the energized conductor.
• Never open the ground connection at a ground pipe or a bus bar unless it has first been disconnected at the point of contact with the equipment it is intended to ground. This prevents an accident if the circuit is energized.
• Make the ground pipe connection first whenever a ground wire on a pole is to be connected.
• Treat coil wires in the take-up reel that was used to coil the wires as energized when removing the reel from the line arms. Attach a rope to the wires at the end farthest from the take-up reel, and wear rubber gloves when tending the reel.
• Ensure proper direction of phase rotation when restoring three-phase power service. This is the responsibility of the person in charge.
• Identify cable while in the manhole before anyone cuts a cable or makes an opening in the lead sheath or sleeve. Check its duct location with that shown on the working print. This working print must have been checked against the installation engineer's map records. In addition, check the cable identity by listening with an exploring coil for the pulsating beat of the interrupter signal. This is the responsibility of the foreman or the person in charge.
• Remove a 3-inch strip of lead around the cable and test it with two voltage detectors after the cable has been identified and grounded. Do this one at a time, at two or more points around the cable and at the center of the exposed insulation.
• Place a hacksaw on the exposed cable insulation adjacent to and touching the grounded lead sheet when cutting cable.
• Open the switch before working on an oil circuit breaker that has an operating bus feed switch.
• Treat series circuits, series lamps, and devices in series circuits as energized unless they are opened by disconnects.
• Never open a series circuit at the point where work is in progress, such as at lamps or other series-circuit devices. Always bridge the point of the circuit being working on with a jumper.

HIGH

Lines and equipment operating at 5,000 volts or more must be de-energized and grounded before any work is started. An exception is overhead lines, which you may work on with live-line tools. Execute all work on energized lines (except in case of emergency) only on an authorized work order. Follow the rules below when working on high-voltage equipment operating at 5,000 volts or more:

• Do not work on more than one conductor at a time with live-line tools.
• Keep live-line tools dry and free from dirt. Thoroughly dry and test tools subjected to damp weather before using them again.
• Protect live-line tools carried on line trucks to prevent scars and abrasions. Waterproof canvas bags, compartments with padded hooks, or bins built into the truck may be used for this purpose.
• Maintain the minimum body clearance from energized lines and equipment (see Table 13-1).

  Table 13-1. Minimum body clearance

  Operating Voltage (kilovolts)	Minimum Distance (feet)
  5 to 7.5	1
  7.5 to 12	2
  12 to 33	3
  33 to 66	4
  66 to 132	5
  132 to 220	8

  Perform all work on de-energized circuits between two sets of grounds. Place one set on the first pole or structure toward the source of energy and the other on the pole nearest the load.
  Do not ground a supposedly dead circuit without first feeling out the circuit for a static discharge with a switch pole.
  Net off energized equipment properly at the substation before working near it, and install suitable barriers and warning signs.
  Remove substation apparatus from service when wiping, cleaning, repairing, or performing other maintenance. Place hold cards on the main and control switches before starting work. If you cannot see hold cards distinctly, use a red light to illuminate them.
  Do not perform work on any apparatus until the electrical foreman has proved it to be dead and safe.
  Do not approach or touch reactors and connected equipment unless they have been disconnected from all live lines and have been grounded.
  Do not raise, move, or lower cables that are energized at voltages up to 12 kilovolts more than 18 inches. Do not move cables that are energized at voltages over 12 kilovolts.
  Discharge electrolytic and oxide-film lightning arresters by grounding and shorting the horn gaps before touching the arresters.

CIRCUITS

DE-ENERGIZED

Do all electrical installation work on a de-energized (dead) circuit if possible. Most electricians rip the main service-entrance switch, remove the fuses, and then tag the switch. The tag should give the electrician's name, the date, and the time that he turned the switch off. If existing conditions do not permit this procedure, de-energize the circuit being repaired or modified by removing the branch circuit fuses or tripping the circuit breaker connected to the branch circuits to OFF.

HOT

Working on hot circuits is not recommended except in emergency situations. In such situations, only experienced personnel who have been cautioned on the dangers involved should work on these circuits. AC voltages as low as 67 volts and DC voltages as low as 110 volts have caused death by electrocution. When working on a hot line, closely follow the procedures listed below:

• Insulate yourself to prevent your body from becoming a conductor path for the current flow.
• Work on only one side of the circuit at a time.
• Use insulating gloves at all times and stand on nonconducting materials.
• Ensure that all equipment, tools, and wearing apparel is dry, because dry materials offer more resistance to the flow of electricity than do moistened or wet items.

PROTECTION

Fuses or circuit breakers are installed as overload and short-circuit protection for circuit components and connected loads. Limit their selection with regard to ampere rating to the maximum value allowable for the smallest conductor or equipment used in the circuit. For example, if an electrical device has a 15-ampere fusible rating and it is connected to a circuit wired with No 12 conductors rated at 20 amperes, the fusing of the circuit should be 15 amperes. Tables B-12 and B-13 list the current requirements for single-phase and three-phase AC motors at different voltage levels.

OVERLOAD

Frequently blown fuses or tripped circuit breakers indicate short circuits, grounding, or circuit overloads. Do not solve this problem merely by installing larger fuses than those recommended for use in the circuit because this exposes both the building and the personnel to an electrical fire. Instead, determine the cause of trouble and rewire overloaded circuits by increasing the wire size of the run or dividing the connected load into several circuits.

BYPASSED

Do not use jumpers to bypass the fuse or remove the circuit-breaker protection from the circuit except when testing for short circuits. These primary safety devices are of vital importance in a circuit installation. If these protective devices are bypassed, the electrical installation loses its circuit-current limitation and short-circuit protection. If the devices are removed, the troubles that caused the power interruption or circuit failure will not be isolated to the local circuit but will cause the rest of the fuses to blow or the circuit breakers to operate, cutting off the entire system from power.

TRANSFORMERS AND CIRCUIT BREAKERS

Take the following safety precautions when working on transformers and circuit breakers:

• Prevent moisture from entering when removing covers from oil-filled transformers. Do not allow tools, bolts, nuts, or similar objects to drop into the transformers. Tie tools or parts with suitable twine. Have workers empty their pockets of lose articles such as knives, keys, and watches. Wipe all oil from transformer covers, the floor, and the scaffold to eliminate slipping hazards.
• Exhaust gaseous vapor with an air blower before allowing work in large transformer cases because they usually contain some gaseous fumes and are not well ventilated. If you feel any effects from gas while working in a transformer case, give an alarm immediately and get out into the fresh air.
• Stay away from the base of the pole or structure while transformers are being raised or lowered.
• Ensure that anyone working on a pole or structure takes a position above or well clear of transformers while the transformers are being raised or supported with blocks.
• Ground the secondary side of a transformer before energizing it except when the transformer is part of an ungrounded delta bank.
• Make an individual secondary-voltage test on all transformers before connecting them to secondary mains. On banks of three transformers connected Y-delta, bring in the primary neutral and leave it connected until the secondary connections have been completed to get a true indication on the lamp tests.
• Disconnect secondary-phase leads before opening primary cutouts when taking a paralleled transformer out of service. Do not disconnect secondary neutral or ground connections until you have opened the primary cutouts.
• Do not stand on top of energized transformers unless absolutely necessary and then only with the permission of the foreman and after all possible precautions have been taken. These precautions include placing a rubber blanket protected with a rubbish bag over the transformer cover. Do not wear climbers.
• Treat the grounded case of a connected transformer the same as any grounded conductor. Treat the ungrounded case of a connected transformer the same as any energized conductor because the case may become energized if transformer windings break down.
• Ensure that the breaker cannot be opened or closed automatically before working on an oil circuit breaker and that it is in the open position or the operating mechanism is blocked.
• Ensure that metal-clad switching equipment is de-energized before working on it.
• Ensure that regulators are off the automatic position and set in the neutral position before doing any switching on a regulated feeder.
• Do not break the charging current of a regulator or large substation transformer by opening disconnect switches because a dangerous arc may result. Use oil or air brake switches unless special instructions to do otherwise have been issued by the proper authority.
• Do not operate outdoor disconnecting switches without using the disconnect pole provided for this purpose.
• Ensure that all contacts are actually open and that safe clearance is obtained on all three phases each time an air brake switch is opened. Do not depend on the position of the operating handle as evidence that the switch is open.
• Do not operate switches or disconnect switches without proper authority and then only if thoroughly familiar with the equipment.
• Remove potential transformer fuses with wooden tongs. Wear rubber gloves and leather overgloves.
• Do not open or remove disconnect switches when carrying load. The oil circuit breaker in series with the switches must always be opened first. Open disconnect switches slowly and reclose immediately if an arc is drawn.

WIRE MARKERS

On equipment or in wiring systems where wires are numerous and circuit identification is difficult, wire markers are a distinct aid to installation. However, use them merely as a guide, and carefully check the condition of each conductor with a test lamp or voltmeter before working on the circuit. This rule also applies to wires that are color coded to conform with the prescribed circuit or ground requirements.

Section IV. Electrical Shock

CAUSES OF ELECTRICAL SHOCK

Electrical shock can be caused by equipment or human failure, equipment and human failure, or a combination of events so unlikely and unusual that it would be almost impossible to prepare for them in advance. Luckily, accidents of this kind are rare. If they were not, working with electrical equipment would be extremely hazardous.

Human failure is prevalent, perhaps because people often have a casual attitude toward the deadly possibilities of electrical circuits and equipment. Scientists have not yet found a way to make electrical equipment that will not shock its users when it is improperly used. Human failure that can lead to electrical shock includes--

• Failing to observe the necessary safety precautions when using or working on equipment that would be perfectly safe if handled properly. For example, a careless electrician might fail to test equipment to ensure that it is de-energized before working on it, or he might not use proper care to avoid contact with equipment or conductors that were known to be energized.
• Making unauthorized modification to equipment or using unauthorized equipment.
• Failing to make adequate repairs on equipment that has already caused nonfatal shocks.
• Failing to test the insulation resistance and the completion of the ground connection after the equipment has been repaired.

GROUNDING

Safety codes require that every 120-volt circuit have a system of grounding. This is a preventive measure, much like oxygen masks on a commercial airliner. During normal operation, the grounding system does nothing; in the event of a malfunction, -however, the grounding is there for your protection.

Grounding assumes that all metal parts of a circuit that you might come into contact with are maintained at zero voltage because they are connected directly to the earth.

Example: A circuit contains a metal pull-chain switch. The hot wire accidentally becomes dislodged from the fixture terminal and comes into contact with the metal canopy of the light fixture. The fixture and the pull chain are electrically charged or hot. You touch the chain or the fixture, a short circuit occurs, and you provide the path to the ground for the electric current. In other words, you receive a shock.

This same situation could occur in any number of places where electricity and conductive materials are together, such as power tools and appliances with metal housings; metal switch, junction, and outlet boxes; and metal faceplates.

The shock in this example could have been prevented if the circuit had a grounding system. A grounding wire connecting the neutral bus bar to the metal housing of the light fixture would provide an auxiliary electrical path to ground in the event of a short circuit. This grounding wire would carry the fault current back to the distribution center and assure that the fuse or circuit breaker protecting the circuit would open, shutting off all current flow.