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The Safe Use of Extension Cords in the Lab

Essential to modern life and a familiar part of our surroundings, yet often not treated with deserved respect. Run over, walked on, crimped in windows and doors, left out in sun and storm alike, strung together, bent, yanked, and strung across rooms and under carpets, strewn across wet grass and through holes in walls, taped up and snarled in tangles that would give a sailor nightmares. Used in the office, in the lab, and in the field, taken for granted until you need one. What are we talking about? American UL power cords, one of the most indispensable tools we use today, but too often with little consideration. And, sometimes used in a fashion that could have disastrous results.



In 1997, more than 12,000 people were treated for electrical shocks and burns; about 2,500 of them were treated for injuries stemming from extension cords.1 In addition, each year about 4,000 injuries associated with electric extension cords are treated in hospital emergency rooms. Half of these injuries involve fractures, lacerations, contusions, or sprains from people tripping over extension cords. Roughly 3,300 home fires originate in extension cords each year, killing 50 people and injuring about 270 more.2 However, with a little care and some precautions, these conveyors of power can be used safely.





We must caution up front, that if you have more than a few Europe VDE Power Cords powering equipment in your lab, it is probably time to either call an electrician to install additional strategically placed outlets, or to rearrange equipment. Likewise, if you have any cords running through walls, up through the ceiling and down somewhere else, an electrician is definitely required. Extension cords should only be used when necessary and only for temporary use. You should always plug equipment directly into a permanent outlet when possible. Where this is not possible, however, you should begin by selecting the right cord for the job.



Indoors or outdoors, the use of extension cords serve different needs and should be selected accordingly. Regardless of location, always use the three-prong type of cord approved for either indoor or outdoor use. In addition, the cord should have a certification label from an independent testing lab such as UL (Underwriters Laboratories) or ETL (Electrical Testing Laboratories) on the package and attached to the cord near the plug.



The amount of current a cord can handle will depend on the diameter of the conductors (copper wire part of the cord). Cords that contain more copper can safely handle more power. The wire size is measured by the gauge of the wire. You will usually find numbers like 16, 14, or 12 gauge on an extension cord package and the cord itself. Now, this is one of those confusing issues. You would think that a 16-gauge wire is bigger than a 12-gauge wire, but it’s not! As the number gets smaller, the thickness of the conductor gets bigger. A 12-gauge wire can safely carry much more power than a 16-gauge wire. Compare the capacity on the label to the intended load.












The purpose of this project was to find out the root cause and influence of environmental factors for equipment failures during the first year of purchase. In addition, implementing electrical safety checks on recurrent intervals to guarantee safe usage of equipment on the patient are discussed.



We conducted electrical safety study on 200 life-saving equipment purchased in the year 2012–2013 in Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry [Table 1]. They belonged to Class I category with detachable Swiss SEV Power Cords of power consumption <1.5 KVA (kilovolt ampere). Class II category, non-detachable power cord equipment and permanently installed equipment were excluded from the testing. Since all the tested equipment were newly purchased, the influence of film resistance was excluded.[4] The electrical safety analyser (ESA) 612 model was used which is capable of measuring low resistance up to 2 Ω with an accuracy of ±2% and leakage current from 0 μA to 1999 μA with an accuracy of ±1%. The analyser incorporates test algorithm of Association for the Advancement of Medical Instrumentation(AAMI)/National Fire Protection Association (NFPA)-99 hospital standard and IEC 62353.[5] All the measurements were manually obtained for better accuracy.



With today’s need for electronic equipment, manufacturers are realizing that in order to prosper—and in some cases to survive—they may have to export to global markets. When designing for global markets, a number of factors are involved, such as being able to provide equipment that is easily adaptable to the needs of the consumer, without any reconfiguration on their part.



One of the main considerations is to ensure the end-user has the correct means of connecting to their local mains supply. It’s also important to follow standards and country-specific regulations. Choosing the right components in the product design is essential as is identifying them in ways that others can understand.



Sometimes electrical terminology can be confusing because different people use different terms to mean the same product. For example, words that describe the means of connecting electrical equipment to a power source may be called a detachable or non-detachable cord, an appliance cord, a cable, a cable assembly, an interconnection, or a power supply, to name a few. They may also be called a power cord, a cord set, a jumper cord, and a connector power cord.



For the purpose of this article, the following terms, which are used at Interpower, will be defined: power cord, jumper power cord, connector power cord, cord set, and jumper cord set.