ELECTRICAL MEASURING TOOLS AND INSTRUMENTS
In electrical work, measuring tools and instruments play a vital role in ensuring that every wiring installation, repair,
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| Term | Definition |
|---|---|
| ELECTRICAL MEASURING TOOLS AND INSTRUMENTS | In electrical work, measuring tools and instruments play a vital role in ensuring that every wiring installation, repair, |
| and maintenance activity is accurate and efficient. Accurate measurement prevents electrical faults, ensures safety, and | |
| contributes to the overall quality of the electrical system. These tools are carefully selected and identified according to | |
| the type of work, materials, and job requirements. | |
| Some of the commonly used measuring tools and instruments in electrical work include the multimeter, clamp meter, | |
| kilowatt-hour meter, insulation tester (megger), vernier caliper, push-pull rule, metric rule, and steel rule. | |
| A. Electrical measuring instruments | – used to measure electrical quantities such as voltage, current, resistance, and power consumption. |
| B. Mechanical measuring tools | – used to measure physical dimensions, distances, and diameters of materials. |
| 1. Multimeters | are considered as functional test instruments. By operating a multi position switch on the meter, they can be quickly and easily set to be a voltmeter, an ammeter, or an ohmmeter. They have several settings called "ranges" for each type of meter and the choice of alternating current (AC) or direct current (DC). |
| Some multimeters have additional features such as transistor testing and ranges | |
| Multimeters come in two types: | |
| a. Analog multimeter | – uses a needle to display readings on a scale. It is sensitive and suitable for observing gradual changes in readings. When buying one, ensure it has high sensitivity (at least 20kΩ/V on DC ranges). |
| b. Digital multimeter (DMM) | – displays readings numerically on a screen, providing more accurate and stable measurements. It is user-friendly and ideal for beg inners and professionals alike. Proper use of a multimeter includes checking the correct range and polarity, handling the test probes safely, and ensuring the meter is properly calibrated. |
| 2. Clamp Meter is a measuring instrument used primarily to measure the current flowing through a | |
| conductor without disconnecting it from the circuit. The jaws of the clamp open to encircle the | |
| conductor, allowing current measurement through electromagnetic induction. This tool is especially | |
| useful for testing live circuits safely. | |
| Clamp meters may also include functions to measure voltage, resistance, and continuity, making | |
| them a valuable addition to an electrician’s toolkit. Like multimeters, clamp meters are available | |
| in analog and digital types and can measure both AC and DC currents depending on the mode l. | |
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| GRADE VII – TECHNOLOGY EXPLORATOTY (ELECTRICITY AND ROBOTICS) | |
| 3. Kilowatt-hour Meter (Electric Meter) | |
| The kilowatt-hour meter is a device used by electric utilities and | |
| consumers to measure the amount of electrical energy consumed over | |
| time. It records energy usage in kilowatt-hours (kWh), which serves as | |
| the basis for billing. There are two types of electric meters: | |
| • Analog (electromechanical) meter, which has a rotating disc that | |
| spins according to the amount of energy consumed. | |
| • Digital (electronic) meter, which provides more precise read ings and | |
| can record energy usage at different times of the day. | |
| Some modern smart meters can transmit data directly to the power company, allowing for real-time monitoring | |
| and more efficient energy management. | |
| 4. Insulation Tester (Megger) | |
| The insulation tester, commonly known as a megger, is a specialized | |
| instrument used to measure the insulation resistance of electrical conductors, | |
| cables, and equipment. It helps determine whether insulation is still effective | |
| in preventing current leakage. This test is important for detecting faults in | |
| motor windings, cables, and electrical installations, ensuring safety and | |
| preventing short circuits or elect rical shocks. Mergers usually apply a high | |
| DC voltage to the circuit and measure the resulting resistance in megaohms | |
| (MΩ). | |
| 5. Steel Rule | |
| A steel rule is a straight measuring tool made of stainless or tempered steel, | |
| commonly used for short measurements. It is durable, resistant to wear, and often | |
| has both metric and English graduations. Some steel rules feature a hook end for | |
| accurate positioning when measuring from edges or corners. Electricians use | |
| steel rules for precise layout work, such as marking positions for conduit or | |
| electrical boxes. It is sometimes referred to as a machinist’s scale. | |
| 6. | |
| 7. | |
| Push-Pull Rule (Tape Measure) | |
| The push-pull rule, also known as a tape measure, is used to measure | |
| longer distances, usually from a few centimeters to several meters. It is | |
| commonly used in laying out electrical fixtures, conduit runs, and | |
| wiring installations. It has a retractable steel tape housed in a case, | |
| which makes it easy to carry and use in fieldwork. Some models include | |
| a lock mechanism to hold the tape in place while measuring. | |
| Vernier Caliper | |
| A vernier caliper is a precision measuring tool used to measure internal and external dimensions, such as the | |
| diameter of wires, thickness of metal plates, and inner diameters of holes. It has two sets of jaws and a sliding | |
| scale (vernier scale) for reading measurements with great accuracy, typically up to 0.02 mm. | |
| Some advanced calipers are digital, providing direct readings | |
| on a screen, while others are dial-type for easier reading. | |
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| GRADE VII – TECHNOLOGY EXPLORATOTY (ELECTRICITY AND ROBOTICS) | |
| 8. | |
| Micrometer | |
| A micrometer, sometimes called a micrometer | |
| screw gauge, is another precision measuring | |
| instrument used to measure small dimensions | |
| such as wire diameters, sheet thickness, and | |
| small components. It is more accurate than a | |
| vernier caliper and is commonly used in | |
| manufacturing and electrical workshops where | |
| high precision is required. | |
| Measuring tools and instruments are essential in all aspects of electrical work—from design and layout to installation | |
| and testing. Understanding their functions, proper use, and maintenance ensures accurate results, promotes efficiency, | |
| and enhances safety. Whether it is measuring voltage with a multimeter or checking dimensions with a caliper, these | |
| tools help electricians perform their tasks with precision and professionalism. |