June 29, 2011
The do's and don'ts of power strips
During a recent Kansas Department of Labor worker safety inspection, the university received a citation for use of power strips in a maintenance shop. While at first blush it seems a little strange, after all, we use these power strips at home. In addition, they are inexpensive and readily available. So what’s the problem?
Power strips, also known as relocatable power taps, strip plugs, power taps and temporary power taps were invented and designed to be used as a multiple outlet extension in the laboratory and at home. Officially called relocatable power taps, they are listed by Underwriter Laboratories Inc. under standard UL1363. Those power taps have some degree of electrical surge protection and electrical noise filtering for the protection of sensitive electronic equipment are also known as transient voltage surge suppressors.
Relocatable power taps and transient voltage surge supressors are only designed for use with a high concentration of low-powered loads such as computers, audio and video equipment, musical instruments, home movie lighting, home workshops and laboratory equipment. They are not intended for use with high load equipment such as refrigerators, coffee pots, space heaters, microwave ovens, toaster, toaster ovens, fans and shop equipment. Essentially anything with an electric motor and possibly a pulley and belt.
Relocatable power taps and transient voltage surge supressors are not extension cords. Power taps are not considered temporary wiring. Although one of the alternative names is temporary power taps, the temporary refers to the physical mounting of the device. Physical mounting of relocatable power taps is permitted as long as removal does not require the use of tools.
According to the UL listing, installation instructions for relocatable power taps includes:
- Intended to be directly connected to a permanently installed receptacle;
- Not intended to be series connected (daisy chained) to other relocatable power taps or to extension cords;
- Not intended for use at construction sites and similar locations;
- Not intended to be permanently secured to building structures, tables, work benches or similar structures, nor are they intended to be used as a substitute for fixed wiring; and
- The cords are not intended to be routed through walls, windows, ceilings, floors or similar openings.
Keep in mind the UL requirement on permanent securing. It is often desirable to secure the relocatable power taps to avoid damage but secured such that no tools are required to remove it. Do use relocatable power taps for their intended purpose and with the intended equipment or loads. Avoid physical damage, exposure to water or wet locations.
Although relocatable power taps are allowed for use in laboratories, use them safely and properly. Consider the load before plugging into a relocatable power taps. Do not plug in heavy appliances with high-powered loads, plug relocatable power taps into extension cords or other relocatable power taps, use outdoors or on construction sites. Remember, living better with electricity safety is the key.
1Original monograph written by Professor Emeritus John “Grizzy” Grywacz, U.S. Department of Labor, OSHA National Training Institute, oshaprofessor.com, revised September, 2008.