By Molex
In circumstances that call for temporary power on most electrical construction projects, the long-standing approach has typically been to cobble together an electrical system using whatever extension cords and portable power supplies that may be on hand. Upon completion of the job, these power boxes, power cords, and string lights were often treated as disposable items, thrown away or — worse yet — left behind, concealed by walls and drop ceilings.
Although applications that call for portable power are inherently impermanent, it’s important not to sacrifice safety and increase the risk of trip-and-fall, electric shock, or other injuries. In fact, since these temporary power scenarios typically require a significant amount of handling and transportation, extra attention should be paid to make sure the portable power equipment is safe, reliable, and built to survive.
Electrocution is considered one of the “fatal four” causes of construction worker deaths, accounting for 82 fatalities in 2016, according to a U.S. Bureau of Labor Statistics report. That same year, exposure to electricity accounted for 1,640 nonfatal injuries involving days away from work in the United States. The total cost of work injuries was $151.1 billion, including wage and productivity losses of $49.5 billion, medical expenses of $33.8 billion, and administrative expenses of $48.3 billion. Ensuring your temporary power equipment provides maximum safety protection can not only help prevent injuries but also protect companies from liability.
Out-of-the-Box Thinking
Portable power boxes come in many shapes and sizes. They are typically designed in a cubed or rectangular shape with metal railed support legs, which keeps the unit up off the ground.
You can order them in a variety of amperage ratings with various plug and receptacle configurations. Some units are constructed of painted steel while others are made of vulcanized rubber. A portable power unit featuring 100% rubber construction is resistant to shock, impact and corrosion, and is lighter in weight than its steel counterpart. Since most portable power boxes will be exposed to the elements, it’s a good idea to make sure the unit is designated for temporary indoor or outdoor use.
A Sturdy, Secure Connection
When drawing various levels of current in a portable power application, it is also important to consider power management and ensure a balanced AC current load between phases. Systems that offer numbered and/or color-coded receptacles allow users to intentionally and evenly distribute current loads, build a better running portable power network, and reduce the risk of power shortage.
For safe and reliable use in outdoor environments — and added peace of mind for owners — power boxes should be Type 3R weather-resistant, UL-certified and meet NEC regulatory compliance by featuring legs that keep electrical components 6 in. above ground level.
Balance of Power
Running from those portable boxes should be power products featuring ground fault circuit interrupters (GFCIs). Designed for protection, reliability, and safety wherever portable power or power cords are used, these devices can prevent the occurrence of serious injury or death associated with electrical accidents on construction sites. Since being required for use in the late 1970s on 120V, single-phase, 15A and 20A temporary receptacle outlets used on construction sites, GFCIs in the construction industry have saved between 650 and 1,100 lives, according to OSHA reports. Since their introduction, the requirements for GFCIs have continually expanded to include additional locations.
GFCIs, which should be used in any indoor or outdoor area where water may come into contact with electrical products, can be placed on individual electrical power cords (in-line GFCI) or deployed systemically to protect an entire system from ground faults, nuisance tripping, and other hazards. It’s important to select code-compliant GFCI components from a reliable source that can ensure all parts are compatible.
Fully integrated watertight wiring systems are now offered to deliver best-in-class GFCI protection in the toughest, wettest, most abrasive job sites and industrial plants. Proper utilization of the right technologies designed for the job can help prevent the causes of many electrical-related accidents, injuries, and deaths.
String of Good Fortune
To safely perform every task on a construction site, proper lighting is essential. With the safety and cost benefits associated with LED technology now being made available in several portable lighting solutions, these traditionally disposable items can now also be viewed as reusable assets, getting allocated to a job site and then scanned back into inventory at the end of the job.
When compared to a continuously operating 10-light string of incandescent bulbs, a 10-light LED string is capable of saving building owners or general contractors up to $1,300 per year in energy costs per string.
Traditionally, when using incandescent lamps, each 10-light string must be powered from its own breaker-protected outlet. If two strings were to be connected end-to-end, the power draw would exceed the rating of the circuit breaker (15A/1,875W), causing the breaker to trip. A 10-light LED string light may draw as little as 140W, so in the construction of a multi-floor office building, users may be able to power the temporary lighting for the entire floor using multiple strings connected end to end from a single 15A/1,875W power outlet. This leads to further reduced costs such as less temporary wiring, smaller wire gauges, and fewer generators required to support temporary lighting.
LED string lights are also more compact and impact-resistant than their incandescent counterparts, leading to less downtime for lamp replacement and reduced maintenance costs. Incandescent bulbs have a typical life span of about two months. Over the course of a year, that can add up to 60 changes, proving to be cost prohibitive for contractors in terms of labor for bulb replacement and workflow disruptions.
The integrated design of some LEDs means there are no other parts to source and keep on hand. The elimination of a guard or cage in LED string lights also provides 4 in. to 5 in. of extra headroom, a significant benefit in some constrained spaces.
In temporary power applications, maintaining the same level of safety and reliability one would expect from a permanently installed circuit breaker or panel is essential. Choosing products that offer maximum durability and safety protection can go a long way toward helping to reduce the risks of a power outage as well as any potential injuries. In addition, by investing in a temporary power system using components made of higher quality materials that are built for reuse, demonstrable cost-of-ownership and energy-efficiency savings can result, saving significant time, money, and administrative hassle.
