Not many things can shut down an organization’s operations faster and more completely than a power outage. Backup power sources may keep critical functions running temporarily, but power must be restored quickly to limit costly work disruptions.
Keeping a building’s electrical system in good operating condition requires regular maintenance, identifying potential problems, correcting them before they can cause serious issues, and reacting quickly to make emergency repairs when necessary.
Electricians can use basic tools to install a system and make repairs, but often, specialty tools are required. A critical first step—whether doing routine maintenance or repairs—is testing the system to identify faults. Proper testing also is a critical step in preventing shock or electrocution.
Testing comes first
To make those tests, an impressive array of testers is constantly being improved and updated.
Leah Friberg, education and public affairs manager, Fluke Corp., provides an overview of basic testers that check an electrical system’s performance and identify problems.
“If there are live electrical systems anywhere in the vicinity,” Friberg said, “it is critically important to do a first pass with a noncontact voltage detector to catch instances of unexpected electrification.”
Friberg said that installers frequently make grounding mistakes, resulting in stray voltage and unintentionally electrified equipment, such as ballasts, pipes and other components.
“Systems that have been updated over time sometimes inadvertently result in multiple supply points. Just because the main supply has been de-energized doesn’t guarantee that the area is now de-energized. These two points apply to any maintenance work that is simply near electrical systems but most particularly to instances where a worker may be cutting into materials and coming into contact with wiring, conduit, etc. Until the system has been verified to be de-energized, it is essential to wear appropriate personal protective equipment [PPE],” she said.
From there, most electricians keep it simple, using an electrical tester or fork tester to verify presence and amount of voltage, Friberg said. Tracing circuits using continuity checks is most easily done with a multimeter.
“Again, the most important point here is safety,” she said. “Always use a safety-rated electrical tester. Solenoid testers do not have fuses to protect the user from inadvertent contact with excessive voltage and, therefore, do not meet NFPA 70E or OSHA standards for qualified electrical test tools.”
“For circuit tracing,” Friberg said, “a multimeter is handy. For load analysis, a current clamp will be necessary, either a clamp meter or a current accessory for a multimeter.”
Solenoid testers have been replaced by electronic testers that still handle basic measurements yet are safer (CAT IV, 600V and CAT III, 1,000V rated); use light, sound and vibration to indicate voltage; and can provide other electrical tests, such as continuity and ground fault.
A fork tester, more formally called a voltage, continuity and current tester, has open jaws that can slide around a conductor in tight spots without clamping or breaking the circuit.
A clamp meter has most of the basic functions of a digital multimeter and can measure large alternating currents (AC) when its jaws or flexible current probe are placed around a conductor.
Inspecting a system and environment with a simple infrared thermometer is a good first step, Friberg said. Live electrical systems will show up as higher temperatures, helping verify a de-energized state, and differences in temperature between like components also can indicate problems.
However, it may be difficult to be sure every component that could be live is scanned while also watching the numeric readout.
“Newer infrared thermometers are available with a thermal heat map,” Friberg said. “These thermometers have multiple infrared sensors that they combine into a thermal picture, so the user can see all at once where any and all hot spots are, while still being far simpler to use than a full thermal imager and far less expensive. A thermal imager or infrared camera makes sense for detailed inspection and troubleshooting work, where smaller components and/or tighter differences in temperature are involved, or for repeated preventive maintenance. Newer thermal imagers also connect wirelessly to multimeters and other electrical tools, allowing the user to see the electrical readout display on screen alongside the temperature value.”
Indeed, the benefits of thermal imaging are known to many homeowners who take advantage of power company offers for free home “audits” to determine where their homes are leaking warm air. Contractors also are offering the service for a fee.
On the commercial side, extremely accurate and sensitive handheld thermal imagers are used to make temperature measurements with extreme accuracy to sweep electrical installations for temperature differences caused by bad connections, load imbalances, overloaded transformers and other deviations within a system.
Overheated components or components that are breaking down can be invisible to an electrician but are immediately apparent to trained thermal imaging specialists using infrared cameras. Detecting and correcting such problems can avert fires and shutdowns that can have catastrophic consequences for manufacturing plants, commercial organizations and government facilities.
Thermal imaging is the primary inspection method for ensuring data centers are up and running, often 24 hours per day, seven days per week. Thermal imagers also are invaluable for keeping a facility’s information communications technology (ICT) systems running, an indispensable element in daily operation, often 24 hours per day. A data system comprises multiple, interdependent components. Thermal scans can immediately identify heat issues of utility transformers, standby generators, transfer switches, main switchboards, uninterruptible power supplies (UPS), power distribution units (PDUs), and server racks. Because precise temperature control is necessary in the data center, the facility’s heating, ventilation and air conditioning systems also are critical.
Whether issues are found during routine inspections, a power failure, or with isolated system components, electricians usually make repairs with basic tools. However, depending on the project and circumstances, other tools may be useful or required.
Examples include portable lighting, ranging from flashlights and compact battery-operated floodlights for illuminating small work areas to multiple generator-powered units for lighting large spaces; video borescopes for viewing hard-to-access places; portable, battery-powered vacuums for cleaning up spaces; cable locators and fault finders for locating buried cables; and other tools.
Demolition tools may be required to make repairs shielded by walls or under floors. heavy-duty electric demolition hammers are designed to chip or break up concrete. These hammers feature an internal piston that drives impact energy through a chisel into the concrete, causing it to break or fracture, said Mitch Burdick, concrete tools product manager at Bosch Tools.
“Electricians are more likely to use a rotary hammer than a demolition hammer,” Burdick said. “They are primarily concerned with running pipe and wiring from a power supply to a house or building or running pipe throughout a large commercial building. In many cases, electricians may have to drill through thick foundation, walls or many layers of brick/block material, which would require a large rotary hammer. Small rotary hammers can be used to drill smaller holes to secure pipe to concrete walls. Should any chiseling or light-duty demolition work be required, rotary hammers can easily be switched to demolition mode.”
Insulated tools are required when working near energized circuits. Pliers, screwdrivers, cable cutters, strippers, crimpers and most other basic electrician’s tools are available in insulated versions, often packed in kits.
Genuine insulated tools are identified by the international 1,000-volt (V) rating symbol, certifying they have been individually subjected to 10,000V and passed other tests stipulated in ASTM standard F1505. True insulated tools also comply with the International Electromechanical Commission (IEC) 60900 standard.
Be aware that many conventional hand tools have padded grips but are not insulated tools. If they don’t have the international 1,000V rating symbol, they are not genuine insulated tools (see example image on this page).
NFPA 70E guidelines for working around exposed, energized circuits apply to insulated tools as well as protective clothing and equipment, and complying with its provisions will result in compliance with OSHA regulations.
Insulated tools are available from many well-known electrical tool suppliers, including Cementex, Certified Insulated Products, Channellock, Greenlee, Ideal, Klein, Wiha and others.
Editor’s Note: Insulated tools reduce the risk of working near energized circuits. As do most industry organizations, Electrical Contractor recommends always de-energizing equipment before working on it. If that is impossible, applicable codes and standards—and use of insulated tools and PPE—must be followed.