REPORTING- LESSON 3: SECTION 5 – Common Test Instruments & their Proper Use for Qualitative Analysis


Introduction Home inspections are primarily visual inspections; however, many home inspectors use tools during the normal inspection process to confirm or verify visual information, and to conduct further analysis of defects. The following is a discussion about some of the commonly used tools. Inclusion of a tool in this discussion does not mean that the tool is required, and exclusion does not mean that the tool has no value. Each home inspector should make a business decision about which tool to purchase, when to use them, and whether to charge additional fees for their use.

Three-light Receptacle Tester A three-light receptacle tester is intended to determine if a receptacle is wired correctly. Some also have a button that allows testing of the GFCI function of GFCI receptacles and circuit breakers. Refer to the Electrical System chapter for more about using these testers to test GFCI operation. These testers can detect common receptacle wiring errors such as reverse polarity (hot/neutral reverse), disconnected neutral, and disconnected ground. Most home inspectors use these testers, and their use (or use of a more sophisticated instrument) is required by some SoPs.

These testers can produce inaccurate results. They cannot detect multiple wiring errors. They may provide inaccurate results caused by problems with equipment connected to the receptacle branch circuit. They will produce an inaccurate result if a bootleg ground has been installed; this is when the receptacle grounding terminal is connected to the receptacle neutral terminal.

The home inspector should not report that a receptacle is incorrectly wired based on the results from a three-light tester. The incorrectly wired receptacle should be reported as having tested as incorrectly wired and should be referred for further evaluation. Similarly, the home inspector should not report that receptacles are correctly wired based on results from a three-light tester. The correct finding is that no wiring errors were detected.

More sophisticated instruments, usually called circuit analyzers, are available. These devices are more accurate than three-light testers and can detect more defects. They can cost a few hundred dollars compared to around ten dollars for a three-light tester. Circuit analyzers are not required by SoPs and are used by relatively few home inspectors as compared to three-light testers.

Voltage Sniffer This tool is also known as a voltage detector, voltage tester, and a tick tracer. A voltage sniffer detects voltage at wires, receptacles, switches, and other locations where electricity is present. It does so without touching the energized component by detecting the magnetic field emitted by electricity. It emits a beeping or ticking sound when voltage is present. This tool is a good safety device for home inspectors, especially when encountering potentially energized wires in attics and crawl spaces. It is also useful for determining if electricity is present at receptacles and switches.

Use of a voltage sniffer is not required by SoPs. Their use by home inspectors is common in most markets.

Multimeter This tool is also known as a clamp-on ammeter, which describes one of its most commonly used functions. A multimeter is most commonly used by home inspectors to measure current drawn by appliances such as condensers, electric water heaters, and electric heating elements. The home inspector opens the jaws of the multimeter and clamps them around one of the energized wires serving the appliance. Probes can be used to measure voltage and resistance in a circuit.

Use of a multimeter is not required by SoPs. Their use by home inspectors is varies between markets.

Probe Thermometer A probe thermometer is a temperature measurement device that has a thin metal probe about six inches long that may be inserted into the object being measured. Typical uses of a probe thermometer involve determining the temperature drop across the air conditioning evaporator coil and hot water temperature.

Use of a probe thermometer is not required by SoPs. Their use by home inspectors is common in most markets.

Carbon Monoxide (CO) Detector A carbon monoxide gas detector detects the presence of carbon monoxide. Typical uses involve testing for the presence of CO in the house, around fuel-burning appliances, and in vents and chimneys. Less expensive models provide an audible tone that varies with the amount of gas detected. More expensive models provide a digital display of the CO amount detected.

Use of a CO detector is not required by SoPs. Their use by home inspectors is uncommon in many markets. In most markets, a CO detector may be used as a confirming tool but should not be used as an inspection tool. The home inspector should not report the use of a CO detector unless CO is confirmed. In this case, the home inspector should recommend evaluation of fuel-fired appliances as recommended by a qualified specialist.