Temporary Jobsite Power

Power supply on a construction site can be nearly as complex as the job itself. Consequently, most large construction firms either hire outside or use on-staff electrical experts for such functions as demand calculations, generator specification and power access design and setup. Even with these professionals on the job, though, there is still a need for project supervisors and managers to be cognizant and engaged in the pursuit of safe, efficient power delivery.

Power problems and violations can result in fines, endanger worker safety and otherwise wreak havoc on both the project and the company’s reputation. With continuous power on a jobsite being essential to day-to-day operations and timely job completion, effective power oversight by project managers is as important as confirming materials delivery and keeping job timelines on track.

Planning Is Everything

Project managers can play a role in ensuring the best possible outcome for the temporary power installation by working with the electrician or electrical engineer handling specifications and design. If possible, help facilitate the delivery of information that is as detailed and accurate as possible, including double-checking with subcontractors to ensure their stated power needs are accurate.

Always advocate for spare capacity for the job, and reinforce in planning meetings any unique requirements that might make a template system design inadequate. Standardization can reduce complexity and save time, but by itself, it does not guarantee the best outcome.

If your company handles its temporary power specification and design in-house, it is especially important to ensure all planning reflects both the actual job conditions and the current codes. Without an outside company in the loop, your firm will bear the entire brunt of any safety or electrical systems fines, should problems arise. The Occupational Safety and Health Administration (OSHA) levies fines of thousands of dollars for a “serious” violation and up to 10 times that amount for one that is “willful”—the designation for an intentional violation or a repeat violation within a certain number of years.

Of particular importance (and recommended bedside reading) are standard 1910.303 – Electrical, General Requirements, one of the top 10 most violated codes, per OSHA. OSHA 1926 Subpart K, Electrical is also a minefield for construction firms. It governs electrical safety requirements relating to temporary and permanent job site power for construction employees and adopts the National Electrical Code by reference.

Prepare For the Unexpected

A power installation that works well at the start of a project might become outdated after the customer makes a change or a job falls off schedule. Built-in outlets, Camlocks and other receptacles in a generator are a great idea, but an installation with portable power distribution equipment offers the most flexibility when site needs a change. Familiarize yourself with the various types of equipment (transformers, power panels and spider boxes) and ensure in advance that your firm has a relationship with a rental company that provides this equipment.

Additionally, investigate plans in advance for how potential severe weather might impact generators. Weather-resistance features (including winterization packages if appropriate) can make or break the ability of a job to stay on schedule.

Establish the Rules

Encourage the creation of safety meetings for workers, and recommend clauses in agreements with subcontractors that make it clear poor power habits won’t be tolerated. Additionally, suggest to the person in charge of human resources that all site workers be required to read an electrical safety manual.

Most bad power habits contradict rules all workers know but may violate from time to time when they are under pressure or in a time crunch. Many of the top power violations relate to extension cords—a piece of equipment that OSHA documentation says is a common source of construction site hazards. The following are a few examples of OSHA violations your workers and tradesmen should avoid under penalty of dismissal.

• Using an extension cord assembly with improperly connected terminals.
• Placement of extension cords near standing or flowing water. When extension cords and their connectors are wet, hazardous electrical leakage can occur, causing workers who pick up that connector to receive a shock.
• Splicing or taping an extension cord, as well as extension cord repair by anyone other than a qualified person.
• Daisy-chaining extension cords. Extension cords can be up to 100 feet in length before they experience voltage drops. Any power need more than this distance from the power source should be handled via conduit or insulated, commercial cable runs attached to an appropriate distribution center.
• Use of inappropriate receptacles. All receptacles in damp or wet locations must be enclosed in weatherproof boxes and be NEMA 4 or 4X rated. GFCIs are required in temporary power installations for all 20-volt, single-phase, 15- and 20-ampere receptacles. Receptacles on the ends of extension cords must also be of the GFCI type whether or not the extension cord is plugged into permanent wiring.
• Smoking anywhere near a generator.

Additionally, panels and other power distribution equipment must be located in permanently dry locations and accessible only to qualified workers. It is also a sound practice to limit exposure of connectors and tools to excessive moisture by using watertight or sealable connectors.

Require Watchfulness

In each electrical safety meeting (as well as in subcontractor agreements), require that site workers notify the job superintendent or project manager immediately if they notice any of the following signs of impending trouble.

• Circuit breakers that trip frequently. When a circuit shuts down repeatedly, it’s a warning that should not be ignored. (Note that GFCIs can also be tripped by wet connectors and tools. Refer to the previous section for a solution to avoid this occurrence).
• Construction lights dimming when high-voltage equipment starts up. High-demand equipment requires a temporary extra current draw during startup. It can damage sensitive equipment, such as laptops and other electronics that may be in use on the jobsite. A common culprit for dimming lights is either a poor connection at a power distribution panel or an undersized transformer.
• Fuel or oil spills around the generator, or apparent leakages from the unit\’92s fuel system or fuel supply lines.

Protect the Firm’s Investment

If your company owns jobsite generators, it must have an appropriate maintenance plan that takes into account jobsite impurities that frequently circulate in the air, such as dust and material particulates. If the firm rents generators for its jobs, someone must discuss with the rental company exactly what the maintenance program is and who is responsible for it. Ask if the maintenance plan is routine or proactive/predictive, and indicate a preference for the latter.

Proactive/predictive maintenance helps detect damage and defects at an early stage, which reduces the incidence of unplanned generator downtime. Also, confirm that equipment will be installed, serviced and repaired only by certified technicians with a thorough knowledge of standard operating procedures, codes and regulations.

Finally, obtain in writing a satisfactory replacement guarantee should a generator fail or require major service or maintenance during the project. The industrial diesel units commonly used on large construction projects can operate for 12,000 to 30,000 hours before major maintenance is required. However, comparable gas units normally can operate only 6,000 to 10,000 hours before requiring major maintenance.

Be Safe and Smart

Although project managers may not be directly responsible for electrical installations on construction sites, their frequent appearance at the site gives them an excellent opportunity to participate in adherence to best practices. Developing a well-crafted plan for temporary power—and then engaging in sound management and keen observation—will minimize jobsite disruption and rework and facilitate cutover to permanent power when the job is complete. Anything a project manager can do to facilitate these activities will help the job be completed safely and on time. Isn’t that the goal of project management in the first place?