Electrical installation in electronics engineering demands precise use of tools, equipment, and materials to ensure safety, efficiency, and quality in wiring and circuit assembly. In Kenya, where electronics technicians work in diverse environments such as bottling plants, printing works, and retail businesses, familiarity with the classification and proper handling of these tools is essential. This chapter examines the major categories of tools and equipment used in electrical installation, emphasizing their specific functions and relevance to electronics engineering professionals.

3.1 Classification of tools

Electrical installation work needs many different hand tools and instruments, and a technician works faster, safer and with fewer mistakes when each one is grouped by its job. In this topic tools are classified by what they do: cutting, measuring, fixing, crimping, testing and shaping equipment, and a few other support tools. Knowing the class tells the trainee which tool to pick up for a task, what faults to look for before using it, and how to store it.

Two rules apply to every class. First, a tool is chosen for the material and the size of the job, not for convenience. Second, a tool used on or near conductors that may be live must have a sound, insulated handle and be inspected before every use. A cracked handle or a damaged jaw is a reason to take the tool out of service.

3.1.1 Cutting tools

Cutting tools prepare cables, conduits and accessories by trimming, stripping insulation or cutting through metal and plastic. The right tool depends on the material (copper conductor, PVC insulation, steel conduit) and on how clean the cut must be.

Hacksaw

A hacksaw is a frame holding a thin, fine-toothed blade under tension. It cuts steel and PVC conduit, metal rods and trunking to length. The teeth point away from the handle, so the blade cuts on the forward stroke only; lift the pressure slightly on the return stroke. A blade with fine teeth suits thin-walled conduit and metal sheet, and a coarser blade suits thicker material. After cutting, remove the burr from the inside edge of the conduit with a file, because a sharp burr can damage cable insulation when the cable is drawn in.

Metal hacksaw with blade and handle (Source: Wikipedia (Hacksaw))

Stripping knife

A stripping knife has a short blade that removes the outer sheath and insulation from cable without cutting into the conductor beneath. Cut away from the body, angle the blade along the cable, never straight across it, and rotate the cable if necessary. A nick in a copper conductor lowers its current-carrying area and makes a weak point that can heat or break. Where many conductors must be stripped to the same length, a wire stripper with calibrated notches is faster and less likely to nick the conductor.

Side cutter

A side cutter (also called diagonal cutting pliers) has angled jaws that cut wire flush with a terminal or a surface. It trims cable ends, cuts cable ties and clips off protruding strands. It is meant for copper wire and similar soft material; hard steel wire or a hardened screw will notch the jaws.

Side cutter pliers for electronics (Source: Wikimedia Commons)

Pliers

Combination pliers grip, bend and twist conductors and, with their cutting edge near the pivot, they cut wire as well. Long-nose pliers reach into small spaces and form loops at the end of a conductor to fit under a terminal screw. For work near live parts, use pliers with insulated handles that carry a voltage rating marking.

Safe selection of cutting tools

Choose the tool to match the conductor size and insulation type. Keep blades sharp, because a dull blade slips and needs more force. Check handles for cracks, store knives with their edges covered, and cut away from the body and from the hand holding the work.

3.1.2 Measuring tools

Measuring tools give the lengths, angles and levels needed to mark out an installation accurately. A cable cut too short is wasted, and a switch box fixed out of square or out of level is visible for the life of the building. Measuring errors are cheaper to find at the marking stage than after drilling.

Tape measure

A tape measure is a flexible steel tape in a case with a locking button. It measures cable runs, conduit lengths and the positions of sockets, switches and boxes. Hook the end of the tape on the edge of the work, pull it straight and read at eye level. For a conduit run, measure each straight section and each rise and drop, and add a small allowance for bends and for the length needed at each end of the cable. For example, a run of 3.2 m along a wall with two drops of 1.1 m each needs 3.2 + 1.1 + 1.1 = 5.4 m of conduit before allowances.

Retractable tape measure with yellow measuring tape (Source: Wikipedia (Tape measure))

Try square

A try square has a blade fixed at a right angle (90°) to a stock. It marks lines at right angles to an edge, and checks that a mounting board, panel or conduit saddle position is square. Hold the stock firmly against the edge, and mark along the blade with a sharp pencil or scriber. A try square that has been dropped may be out of true, which can be checked by marking a line, turning the square over and checking that both lines coincide.

A try square on a wooden surface (Source: Wikipedia (Try square))

Steel rule

A steel rule is a straight, rigid strip graduated in millimetres and centimetres. It is used for short measurements that need more precision than a tape provides, for example marking drilling positions on a metal enclosure or a back plate. The rule is also used as a straight edge to mark a line. Keep it free of rust and bends, since the accuracy depends on the edge and on readable graduations.

Close-up of a steel rule measuring scale (Source: Wikimedia Commons)

Spirit level

A spirit level has a sealed glass vial containing liquid and an air bubble. When the bubble sits exactly between the marks the surface is level (horizontal), and a vial turned at right angles shows plumb (vertical). It is used to set distribution boards, trunking and conduit runs straight, and to make a row of socket outlets line up. Place the level on the work, read the bubble from directly in front and, if the reading is doubtful, turn the level end to end and read again.

A traditional spirit level tool (Source: Wikimedia Commons)

Care of measuring tools

Measuring tools lose their value if they are inaccurate. Do not use a steel rule as a screwdriver or a try square as a hammer, keep tapes clean and dry, and compare instruments with a known standard from time to time. A metal tape is conductive, so do not use it to measure close to exposed live parts; use a non-metallic measure or isolate the supply first.

3.1.3 Fixing tools

Fixing tools are used to secure components, cables and conduits to their mounting surface. A loose box, a clip that has pulled out or a screw that has stripped its head will become a hazard, so the fixing must be both firm and neat.

Hammers

A claw hammer drives nails and cable clips into wood and, with its claw, withdraws bent nails. For fixing masonry nails, plugs and chisels, a heavier hammer is used and eye protection should be worn. Grip the handle near the end, strike squarely and keep the head free of oil. A loose head is dangerous; replace the handle or the hammer.

Screwdrivers

Screwdrivers drive the screws in terminal blocks, switch plates, socket faceplates and enclosures. The tip must match the screw head: a flat-blade tip for slotted screws and a cross-head tip for Phillips or Pozidriv screws. A tip that is too small or worn slips and damages both the screw and the work. Screwdrivers for electrical work have insulated shafts and handles, and a voltage rating marked on the handle (commonly 1000 V a.c.). Never use a screwdriver as a chisel, a lever or a probe for testing for the presence of voltage.

Red-handled screwdriver on rock outdoors (Source: Wikimedia Commons)

Other fixing tools

Spanners and nut drivers tighten the nuts and bolts on earth clamps, cable lugs and enclosures, and an adjustable spanner should be tightened onto the nut so it does not slip. Cable ties and clamps hold cables in neat bundles, and cable clips hold single cables to a wall at regular intervals. They are fixing accessories, not tools, but the technician must choose a size suited to the cable.

Safety and ergonomics

Insulated handles reduce the shock risk if a tool touches a live terminal, and handles with a good grip reduce hand fatigue over a long day of fixing. Keep the screwdriver in line with the screw and apply pressure in the direction of the screw, and do not hold the item being fixed in the palm of the hand while driving the screw.

3.1.4 Crimping tool

A crimping tool joins a connector (a lug, a ferrule, a plug) to a conductor by squeezing the metal of the connector tightly around the strands. A good crimp is gas tight and mechanically strong, with a connection of low resistance, and it needs no solder. A poor crimp heats up under load and may be the cause of an intermittent fault or a fire.

Types of crimping tools

Ratchet crimpers close in steps and do not release until the full crimp has been made, so every crimp has the same pressure. They are the usual choice for insulated terminals and ferrules. Hydraulic crimpers apply a high force through a hydraulic ram and are used for large cable lugs on heavy power cables. Insulated crimpers have insulated handles, and the jaws are shaped for insulated terminals and ferrules so that the insulation sleeve is not cut. A conductor is always crimped with the circuit isolated.

Insulated crimper with orange handles (Source: Wikimedia Commons)

Modular crimpers are made for network connectors such as RJ45 plugs, and have jaws shaped for the plug and a blade that trims the wires to length.

Kit with modular crimper and network tools (Source: Wikimedia Commons)

Best practice for crimping

1. Strip the conductor to the length recommended for the connector, without nicking the strands.
2. Select the correct die or slot for the connector size, which is often colour coded.
3. Insert the conductor fully, so that the strands show at the end of the barrel and the insulation reaches the barrel.
4. Close the tool fully, and release it only when the ratchet allows.
5. Pull on the connector to test the grip, and look at the crimp for uniformity.

3.1.5 Equipment

Equipment here means the instruments and larger tools that test, hold and shape the components and materials. Each has a specific job, and some of them (the instruments) are also used for measuring electrical quantities rather than dimensions.

Multimeter

A multimeter measures voltage, current and resistance, and many also test continuity and diodes. Before use, select the correct function and range, check the leads for damage, and keep the test probes away from the hands. Measure voltage in parallel with the load and current in series with it. Switching to a current range and connecting across a supply makes a short circuit and can destroy the meter and injure the user. Use a meter of the right safety category for the supply being tested, and switch it off or to the highest voltage range after use.

Digital multimeter with test probes (Source: Wikimedia Commons)

Stock and die

A die cuts an external thread on a rod or the end of a conduit, and the stock is the handle that holds the die. Clamp the work in the vice, start the die square to the work and turn it a half turn forward and a quarter turn back, to break the swarf. Use cutting oil, and clean the die after use to protect the cutting edges.

Vice

The vice holds the work firmly so that both hands are free to cut, drill or bend it. A bench vice is bolted to the bench, and soft jaw covers of aluminium or fibre protect finished surfaces. Clamp the work tightly but not so tightly that the item is crushed, and keep the screw and slides lightly oiled. Check that the jaws line up and are clean before use.

Black metal bench vice on white surface (Source: Wikimedia Commons)

Insulation resistance meter

This meter applies a high direct voltage to the insulation of a cable or installation and reads the leakage resistance in megohms. A good circuit shows a high reading, and a low reading means the insulation is damaged, damp or dirty. The test voltage must suit the circuit, typically 500 V d.c. for ordinary low-voltage circuits. The circuit must be isolated and proved dead before connecting, and sensitive equipment such as electronic devices must be disconnected so that the test voltage does not damage them. After the test, discharge the circuit, since cables can hold a charge. Check the test leads for damage before each use.

Hioki IR-305 insulation resistance meter (Source: Wikimedia Commons)

Earth resistance meter

This instrument measures how well an earth electrode connects the installation to the general mass of earth. It injects a test current between the electrode and a spike driven into the ground some distance away, and uses a second spike to measure the voltage, and from these it displays the resistance in ohms. The result depends on the soil, so note the soil condition and the weather when a reading is recorded. A low reading means that the earth path will carry fault current safely, and a high reading means that the electrode should be improved, for instance by driving it deeper or adding another electrode.

Clamp meter

A clamp meter has jaws that open and close round a conductor and measure the current from its magnetic field, so the circuit does not have to be broken. Clamp round one conductor only. If the jaws enclose both the live and the neutral of a normal cable, the magnetic fields cancel and the meter shows zero or nearly zero, whatever the load. It is also useful for checking load balance across phases and for finding which circuit is overloaded.

Digital clamp meter measuring voltage (Source: Wikimedia Commons)

Pipe bending machine

A pipe bending machine bends conduit to a set radius without flattening or kinking it. A manual bender uses a lever and formers of the correct size, while hydraulic benders suit larger conduit. Select the former for the conduit diameter, mark the position of the bend, and bend slowly to the angle required. Lubricate moving parts and inspect formers for wear before use.

3.1.6 Others

Several other tools support the installation. They do not fit the groups above, but a technician needs them regularly.

Draw wire

A draw wire is a flexible steel or nylon wire used to pull cables through conduit and trunking, and it is also called a fish tape. Push it through the conduit from one end until it comes out at the other, attach the cable to its hook or loop with tape, and pull the cable through, with a second person feeding it so that the insulation is not damaged. Store draw wire on its reel or in a loose coil, because kinks make it hard to push.

Bending spring

A bending spring is a coil spring that is pushed into a plastic conduit before bending by hand. It supports the walls of the conduit from the inside and prevents it from kinking or flattening, and it is removed by twisting it to reduce its diameter and sliding it out. Choose a spring that fits the conduit diameter and check it for damage or deformation before use.

Drill

An electric or battery drill makes holes for fixing boxes, saddles and conduit entries in walls, panels and enclosures. Choose a drill bit suited to the material (a masonry bit for brick and concrete and a twist bit for wood and metal), wear eye protection, and fix small items so that they cannot spin. Remove the plug from a mains-powered drill when changing a bit. Before drilling into a wall, check for concealed cables and pipes.

Chapter Summary

This chapter explored the classification of tools used in electrical installation, covering cutting, measuring, fixing, crimping tools, and essential equipment such as multimeters and pipe bending machines. The proper use, care, and maintenance of these tools were emphasized to ensure safety and longevity. Identification of materials including cables, consumer control units, switches, and conduits was detailed to aid accurate selection for installation tasks. Specifications such as tolerance, make, size, and class were discussed to guide appropriate tool and material choice. The chapter also addressed the importance of reusing materials where possible and the correct disposal methods to minimize waste. Understanding the Bill of Quantities was introduced as a key aspect of project planning and cost estimation. Finally, the processes of listing, assembling, and managing inventory through stock taking and record keeping were highlighted as critical for efficient electrical installation operations.