Chapter 4: Electrical Measurement & Testing Equipment Flashcards
Voltage tester
Indicates whether voltage is present in a circuit
Digital voltage tester
Used indicator lights or a digital readout to report the amount of voltage present. Draws little current from the circuit.
Solenoid voltage tester
Uses a higher amount of current to activate the tester’s solenoid, which indicates the presence of voltage.
What are two small and inexpensive voltage testers?
Circuit tester and noncontact voltage tester
Circuit tester
Has two interchangeable probes and a small light indicating voltage.
Noncontact voltage tester
Can detect voltage through wire insulation or by having its tip pushed partway into a receptacle slot
Receptacle tester
Plugs into a standard-voltage (120V) receptacle. Tells you whether the receptacle is wired properly and is grounded or if it has a wiring problem.
Some receptacle testers can be used with ________ to identify the receptacle’s circuit.
Wireless circuit breaker tester units.
VOM
Volt-ohm-milliammeter
Multimeter
Tests for multiple electrical properties, including voltage, current, resistance, and continuity.
Before using a multimeter you must know the _____ and the approximate ____ and _____ of the circuit or device.
Type of current (ac or dc); voltage; current
Using a handheld meter in a _________ may damage the meter and possibly cause an injury.
High-voltage circuit
Clamp meter
Tests current through insulation by hooking around the wire or cable. May be used in a residential setting to test service wires.
Maximum testing capability of voltage testers and multimeters
240 V and 10 A
Maximum testing capability for clamp meters
1,000 A and 1,000+ V
Insulation tester
Tests the resistance of insulation: whether it is good enough to safely handle the current flowing through the wiring.
How does an insulation tester work?
It applies a preset level of dc voltage and a relatively small amount of current through wiring and checks for losses that can indicate leakage through the insulation.
What are three other names for an insulation tester?
Insulation resistance tester; megohmmeter; meggie.
Earth ground tester
Checks the earth’s resistance to dissipating energy around a ground system.
Soil and its contents- including rock, moisture, and impurities- can vary widely in ________________.
How well it accepts electrical energy.
Soil with ________ provides a less effective ground than soil with ________.
Higher resistance; low resistance.
The resistance of soil can change with ____ and _______ changes.
Time; temperature.
The testing method most commonly used for a single residential ground rod is called ________. This tests a ground rod’s ability to __________.
Fall-of-potential; dissipate energy at its current location.
During new construction, an electrician may conduct a _________ test to determine a suitable location for installing a new ground rod.
Soil resistivity
Phase and motor rotation testers
Used by maintenance electricians to determine motor rotation direction and to check the phase sequence of a motor’s power supply wires.
A tester’s _________ must be higher than those of any equipment the tester will be used on.
Voltage and amperage ratings
What symbol indicates a tool is double-insulated?
A small square inside of a larger square
Proper polarity is important when testing ______ and _______ but not ______ or ________.
Voltage and current; continuity or resistance
The red probe on a tester is ______ and connects to the _______ wire
Positive; hot
The black probe on a tester is _______ and connects to the ______ wire.
Negative; neutral
What readings might you get from a receptacle tester indicating there’s a problem with the receptacle?
Open ground; open neutral; reverse polarity; open hot
