The electrical contractor's job on a typical construction project goes beyond the scope of traditional electrical installations. It's a two-part responsibility that includes the construction or renovation of electrical systems for the structure.
It also requires development and maintenance of temporary construction power when a power distribution system does not exist or is not adequate to supply the work site. When temporary construction power distribution is not designed by an architect or engineer of record, contractors are responsible to design it in accordance with the National Electric Code.
A temporary system must not only perform multiple functions during construction phases, ranging from lighting to the power used by all construction trades, but it must expand as the structure progresses.
Among myriad responsibilities, the scope of a contractor's contractual commitment generally includes designs, permits, approvals, moves, changes, outages, power, utility coordination and removing temporary power sources at the end of construction.
Contractors and specifiers alike can benefit from resources and technologies that are making the process of achieving quality and compliance easier.
Spec Supply Lags Demand
It is clear that construction sites can use large amounts of power in the months between the time a building is being built and the utility grids are live and fully operational. However, the procedures and guidelines for the installation and maintenance of these temporary power distribution systems can be sketchy.
The assumption is that builders will supply specifications detailing temporary power systems. In reality, said NECA Executive Director of Standards and Safety, Brooke Stauffer, contractors are increasingly responsible for developing a viable and compliant temporary power plan.
“In many cases, contracts don't contain any guidelines except a vague injunction to provide a temporary power system for the use of the trades,” said Stauffer. Specifications for temporary power vary from project to project, and although there is no data available to support or negate the content of the industry's contractual agreements, Stauffer's observation rings true with some NECA-member contractors.
Marty Adams, president of Adams Electric Inc., a design-build firm with 30 employees in Pueblo, Colo., performs custom residential and commercial work in southern Colorado. “We provide temporary power on a majority of our projects whether it's renovation, remodel or new construction, but we are supplied specifications only about 10 percent of the time. Specifications are virtually nonexistent, except those that we have designed or assisted a consultant in developing.”
Specifications are provided only slightly more frequently for Mega Power Electrical Services Inc. in Gaithersburg, Md., where President Michael Toman reports that the company is expected to develop its own specifications on 70 percent of its jobs.
Toman said renovation jobs can many times use existing utilities, but new construction projects require new systems. One of the biggest challenges to providing temporary power to both job-site types without specifications is achieving accuracy.
“It's assuring that your temporary power system will be adequately sized and effectively distributed to be able to meet the project's needs when the temporary power system has not been defined in the contract,” he said.
Why, then, are specifications not supplied with more consistency? Some contractors believe the supply of temporary power criteria depends on a company's market niche and location. Others say contractors inherit their responsibility of temporary power distribution because it's where the expertise lies, especially with the growing number of design/build projects. Yet the most plausible answer may be a project's size.
“On average, about half of the job specifications we're provided contain temporary power criteria, but they apply more to large commercial and industrial installations,” said Howard Hughes of Hughes Electric Company Inc., based in Fort Smith, Ark.
“On very large projects, engineering is typically complete and temporary power is usually bid as a separate project,” added Hughes. “On larger projects, specifics are provided and we merely follow them. On smaller projects we're generally expected to provide temporary power for other crafts and we factor this into our bids.”
NECA Integrates Industry Regulations
The NEC (ANSI/NFPA standard 70) governs the installation and maintenance of temporary power systems, but, according to Stauffer, it lacks the level of detail contractors find practical for the variety of projects and methods available today.
One resource contractors can turn to voluntarily-which conforms to NEC requirements-is the National Electrical Installation Standard (NEIS) NECA 200-2002, “Recommended Practice for Installing and Maintaining Temporary Electrical Power at Construction Sites.”
Although contractors must comply with federal, state and local electrical codes when installing any electrical products and systems, Stauffer noted that NECA 200-2002 integrates industry regulations such as NEMA Standard WD 6-2002 for plug and receptacle configurations and OSHA 29 CRF 21926.56 establishing minimum light levels for construction work. NECA 200-2002 also supplements and extends the requirements of GFCI in accordance with NEC Section 527.6 and NECA/EGSA 404 for motor-operated generators.
The standard covers not only parameters for new construction, but also renovation, repair, demolition, maintenance and other similar operations in existing facilities. Designed to address phases from planning to the cutover and removal of temporary power systems operating at 600 volts or less, the objective of the standard is to ensure a safe and reliable energy source for all construction trades until a permanent power distribution system is established.
“We're trying to provide good guidance to contractors and specifiers to provide adequate power systems. It's intended to serve not as an instructional document, but as a compilation of the best installation and maintenance practices of the industry,” Stauffer said.
Hughes said, “It's an excellent document to use as a guideline, and I recommend it highly.”
According to Stauffer, with a capable power system, building trades aren't losing valuable time looking for sufficient power. There's adequate light and multiple outlets for their tools, which reduces disputes and increases productivity on the job site.
Adams added: “The NECA guideline is very helpful to contractors who are attempting a different type of work than what they've done in the past. For us veterans, it gives us different viewpoints and more modern techniques versus what we've been doing for years.”
Trends and Tools
Over the years, several industry shifts have shaped the contractor's responsibility for new construction and renovation projects. According to Adams-a 32-year industry veteran-the requirements for safe installations have grown significantly.
“Contractors are more conscientious. There's stricter enforcement, better technology, more advanced education and therefore stricter guidelines. It's all improved to achieve a safer workplace.”
Hughes pointed out that the timing of cutovers from temporary to permanent power is another area of practice that is evolving.
“Our inspection authority will permit 'early power' by meeting certain criteria. We try to concentrate on getting services completed as early as is practical. This is particularly useful as power requirements tend to grow as the project progresses,” Hughes said.
“When temporary power requirements have been defined within the contract,” said Toman, “we have seen a trend that more specifically defines the type and size of temporary services and also delineates an ever-expanding list of equipment that will require temporary power connections.”
When available, NECA 200-2002 recommends the temporary construction power distribution system use as much permanent power as possible. That is the norm if structures are erected in an established area served by utility power. Contractors are more frequently supplying workplace lighting and power to tools, especially in remote areas, with gas, diesel, LP or natural gas-powered generators.
Needs for generated power vary as widely as the jobs they're used on. Generators' output ranges from as low as four kilowatts up to large skid or vehicle-mounted units capable of producing more than 5,000 kilowatts. In addition to their primary function, today's models generate higher power output from their compact size compared to their predecessors. They're also engineered to produce cleaner power for computers and other electronics that sense the slightest fluctuations in AC power.
For Adams Electric, the on-site power-source decision centers mainly on cost. “I don't say that facetiously, but it's the analysis of how available utility power is compared to the cost of providing that through a utility or a generator. It all boils down to the duration of the project and what is the most feasible source to accomplish your project,” said Adams.
Among the most common technological advancements in temporary power tools and equipment in recent years has been the development of GFCI protective devices and manufactured or custom-built light stringers.
“In the old days, we used pigtail sockets and guards,” said Adams. “We had to build our own light stringers and we threw them away after the jobs. Now they're durable enough to reuse on multiple jobs. Over time, they've become much more cost effective and less time consuming.”
The use of battery-operated tools and equipment is much more prevalent, further increasing worker efficiency and safety. “Instead of 25 extension cords trailing around, you have battery chargers, and these devices often double as portable radios. You still need power, but not as many receptacles. It's a lot easier if you're not tethered,” said Stauffer.
Although contractors will always be tethered to regulations and a wide scope of responsibilities on job sites, the industry continues to be committed to providing resources and recommended practices that light the path. EC
MCCLUNG, owner of Woodland Communications, is a construction writer from Iowa. She can be reached via e-mail at email@example.com.