Fifty years ago electrical contracting was a straightforward field. Contractors strode confidently from job to job installing electrical power systems according to the specs from a design engineer. But times and technology change. Today's contractors must blend the skills of design, civil, and architectural engineers to work on a major electrification project.
*As the years go by, many contractors are diversifying from wiring houses to working with variable frequency drives, fiber-optics, automation controls, and energy management systems. Other firms specialize in design-build electrical generator systems, or power management systems for motors, or electrical field data surveys. Now more than ever, contractors find that quality control, training, safety and project management are key to deliver a top-notch job to the customer.
*Back in 1949, projects were relatively simple, and the electrical portion of the job was a small fraction of the total costs of construction. A contractor would review a project, figure its approximate costs, double the result for overhead and profit, and then present the total figure. Very seldom were multiple bids involved, let alone the long bidders lists that are now common. To stand apart in today's era of construction complexity, electrical-contracting companies demand a new level of timely precise computerized estimating products. Estimating software now takes care of the most tedious tasks-such as adding up all the components of an outlet box installation. Such products as portable takeoff devices, computer-aided design, project management, and report-manager software are all part of the office worker's arsenal today.
The latest generation of computer-aided design (CAD) for estimating is growing with contractors. Clients want drawings with associated pricing to be easily available in design-build, design-assist and bid/spec work. Thus, recent developments link CAD drawing symbols (sometimes called blocks) to the data in estimating programs. Applying CAD in these design and redesign applications brings impressive time and cost savings. Another important development is the ability of different disciplines to jointly share a CAD plan set. For example, in a CAD program used for instrumentation work, the plans from the process group, structural layouts from the mechanical
A powerful property of many DMMs for detecting power quality problems is the Min/Max recording capability, which can store the minimum maximum and average voltage or current over a period of time. Another example: continuity capture, a feature found on some DMMs, is useful for finding intermittent connections on small gauge wires and within wiring bundles. These testers can even uncover intermittent relay contacts.
A graphical DMM is basically a more expensive standard DMM with the function of an oscilloscope (a larger display) that can show a waveform or any other analog-type pattern. The power harmonics meter is a specialized graphical DMM that offers three ways to view harmonics in your power distribution system.
An arsenal of relatively inexpensive equipment is now available to do the job of troubleshooting the universe of copper wiring, such as shorts, opens or crossed wires. Many electrical contractors now own a wire tracing kit designed to help locate circuit paths, identify breakers, and locate shorts, ground faults and open circuits. Users especially like the fact that today's circuit tracers will not interfere with sensitive electronic equipment, so a branch circuit, for example, can be tested under load. Adapter leads and other accessories allow a user to ground circuits and set-up traces without a standard outlet. These tracing wizards can quickly locate a pair of wires in a bundle and handle a variety of wire-sorting tasks.
Fifty years ago, electricians and installers used spirit levels, tape measures, and plumb bobs for laying out conduit runs and cabinet locations. Advances in laser technology are changing that. Because they are small enough to carry in a belt, holster, a lightweight laser tool can quickly set up reference points for many tasks. These include running conduit, positioning hanger systems, installing cable trays, aligning wall boxes, switches and light fixtures; and transferring floor markings to ceilings. One pocket laser, for example, offers self-leveling plumb and level laser beam, as well as an out-of-level indicator signal. Thus, today's laser devices function in crowded drop ceilings or elevator shafts-virtually anywhere.
Power quality monitoring equipment
The maturing of the power-quality industry-Fifty years ago, only a handful of mainframe computers did rapid numbers crunching for industry and government. The people who ran these computers were the only ones worried about power reliability and power-quality issues. Now, silicon chips are etched into almost every piece of equipment being used, and the pace of innovation continues to quicken. Modern personal computers (PCs) and microprocessors are virtually everywhere. PCs, variable frequency drives for motors, and other types of solid state equipment that alter the ac waveform when they draw power, cause aberrations in ac power systems. Thus, power quality is an issue of concern to just about every electrical contractor today.
Whether the facility is a hospital in lightning-prone Orlando, a high rise building in Chicago or an aging paper mill in Michigan, most power quality issues are likely to involve distribution system grounding integrity, voltage fluctuation, harmonics, high frequency noise and voltage transients. So, power-quality monitoring equipment, which can ferret out any one of these power-quality problems at these facilities, have developed dramatically over the past 30 years. Back in 1976, the first dedicated power-quality monitors showed data in a textural format. The second-generation units in 1984, showed graphical printouts of the waveforms.
In the late 1980s, we saw the introduction of the third generation units that offered high-speed sampling, capable of producing a megabyte of data in just milliseconds.
But, gathering in so much data can be "information overload," so the fourth generation power quality monitors turned data into "useful information" by classifying disturbances with such terms as "momentary sag" or "impulsive transient," and the cost of the gear was cut in half.
Soon, technicians will be using even simpler fifth-generation power monitoring units that use fuzzy logic software and other artificial intelligence tools-and their costs will be still less.
*Wiring practices change
In addition to low-voltage control and monitoring circuits, contractors are also installing voice and data installations, security systems, closed-circuit television, card access, microwave systems and satellite communications systems in a big way.
As the complexity of these critical networks increase, the range, diversity and quality of identification materials and tools also have evolved. Unlike the "one-size-fits-all" concept of 20 years ago, identification labels now fit specific applications and accommodate hardware size variations between manufacturers. Able to stand up to harsh industrial environments, today's labels are suitable for a variety of patch panel, terminal blocks and faceplate marking.
These identification materials include preprinted wrap-around and clip-on markers, computer-printable heat-shrinkable sleeves, wraparound labels, carrier/insert systems, pull-tabs and temporary flags for wire and cable identification.
Self-laminating wraparound labels, carrier/insert systems or clip-on markers are products used where tagging is done after wire terminations, or where identification is not permanent. For permanent use, heat-shrinkable full-circle sleeves are used. Today's label creation software packages carry all of the features needed to handle the labeling requirements for an installation, for maintenance, or for troubleshooting.
Lighting equipment Lighting has changed drastically in the last five to ten years. It is not only the change out of fixtures or components. The improvements in light sources are exciting, particularly the miniaturization of the light sources. For example, linear fluorescent T5 lamps (5/8-inch diameter) compared with T8 and T12 lamps (1-inch and 1-1/2 inch diameter respectively) allows the creation of much more compact fixtures. These shallow or slim fixtures are easier for contractors to install, and they are aesthetically more pleasing to the end user.
The miniaturization of light sources can also be seen in high intensity discharge (HID) lamps, particularly metal halide. Today's reduced jacket/or size metal halide lamps offer almost unlimited opportunities in commercial applications. This is especially true considering new technology enables many metal halide lamps to be open fixture rated, and/or filter out UV radiation. Even more exciting than this is the new pulse-start technology for metal halide lamps (lamp/ballast/ignitor integration). These mid-range mid-wattage lamps offer reduced energy consumption and better lumens and life over standard metal halide lamps.
Another interesting innovation is the availability of air-tight recessed downlights designed to prevent excessive air leakage thus conserving valuable energy.
Also, consider that today's residential consumer has a growing interest in home automation technologies-starting with light control systems and extending to security systems-which apply to both new construction and a retrofitting project. With reliable wireless radio frequency lighting control systems there is a big opportunity to reach the untapped existing home market.
Fifty years ago, the concerns for job site safety were much less than we see today. Now, enforcing job safety is mandatory, and safety records must be maintained. Such records fall into four basic categories: injury and illness, medical and exposure; equipment maintenance; and training. Injury and illness records help target the causes, and thus, help to identify measures that can reduce occupational injuries and diseases. Medical and exposure records provide data that ensure the job is free of hazards and they offer information that can help detect, treat and prevent occupational diseases. Maintenance and training records ensure the equipment is safe and employees are able to work safely.
Because every job includes the possibility of injury, and contractors strive to reduce their experience modification rate (EMR), increasingly they are setting up formal programs that include regular safety meetings and other procedures to educate the field force.
One Midwest contractor regularly sends all field supervisors a "safety packet" attached to a memo. The same contractor developed a "Live Equipment" kit that must be used when working on energized switchboards or similar equipment. Carried in a gang box, the kit includes a pair of 36- by 36-inch rubber mats with case, two pairs of rubber gloves, two safety cones, two safety signs, two flame-retarding jump suits, one wand, two hard hats with full face shield, one roll "Danger High Voltage" yellow caution tape, four labeled safety lockout tags, four individually keyed locks with keys, and one 16-ft fiberglass folding ruler.