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Position of the DHHS Safety and Health Program

Extension Cords And Surge Protection Strips


What Electrical Equipment Can Be Used To Extend Power To Portable Electrical Devices Where There Are Insufficient Outlets?
Position Number
04001
Requesting Unit
Department-wide
Issue
What electrical equipment can be used to extend power to portable electrical devices where there are insufficient outlets?
Regulatory Requirements
29 CFR 1910.305(g)(1)(iii)
NFPA 70: 400-8
NCSBC, Volume V: 703.1
Discussion
Outlets:
Electrically powered appliances which are designed and approved to be powered via a flexible cord - called "power supply cords" to differentiate it from extension cords - are required under 29 CFR 1910.305(g)(1)(ii) to "be energized from an approved receptacle outlet." "Receptacle outlet" is defined in 29 CFR 1910.399 as "an outlet where one or more receptacles are installed", and "outlet" is defined as "a point in the wiring system at which current is taken to supply utilization equipment." Article 210 C. (Required Outlets) of the National Electrical Code (NEC), 1999 edition defines and regulates where outlets must be installed, and states in 210-50(b): "A receptacle outlet shall be installed wherever flexible cords are used." (210-50(a), which states "A cord connector that is supported by a permanently installed pendant shall be considered a receptacle outlet", provides by inference that the end of a flexible cord which will accept an attachment plug is a "cord connector" and not a "receptacle", unless specifically defined as such in code.)
In a permanent wiring system, the outlet must be a permanently installed part of that system under the guidelines of NEC-1999 370-23 (a) through (h). The outlets in cubicles are considered a permanent part of the wiring system if installed under the guidelines in the NEC-1999 Article 605. If electrical power is needed, it is the intent of the regulations that a permanent outlet be installed at a location accessible to the appliance and its power supply cord.
On October 30, 1996, the Safety and Health Director in his then-role as NCOSH Safety Compliance Officer contacted via telephone Mr. Mark Ode, Senior Electrical Specialist with the National Fire Protection Association. Mr. Ode confirmed that it was the intent of the National Electrical Code to require the installation of permanently mounted receptacle outlets wherever cord-and-plug powered equipment was installed, and that the space between the outlet and the equipment should be no greater than the length of the equipment's flexible cord.
Extension Cords:
For the purposes of this discussion, extension cord is defined as an electrical apparatus consisting of a flexible cord of a type listed in Table 400-4 of the National Electrical Code (NEC), 1999 edition, with an attachment plug at one end and one or more receptacles at the other, with no overcurrent mechanism, ground fault circuit interrupter, or similar device incorporated into its design.
The OSH standards, the North Carolina Building Code, and the National Electrical Code do not prohibit extension cords or their use. Rather, they are addressed indirectly according to how they are used, either as temporary or permanent wiring.
29 CFR 1910.305(g)(1)(iii) reads as follows:
"Unless specifically permitted in paragraph (g)(1)(i) of this section, flexible cords and cables may not be used:
(A) As a substitute for the fixed wiring of a structure.
(B) Where run through holes in walls, ceilings, or floors.
(C) Where run through doorways, windows, or similar openings.
(D) Where attached to building surfaces.
(E) Where concealed behind building walls, ceilings, or floors."
29 CFR 1910.305(g)(1)(i) provides several uses of flexible cords which are permitted, including as pendants, wiring of fixtures, connection of portable lamps or appliances, elevator cables, wiring of cranes and hoists, connection of stationary equipment to facilitate their frequent interchange, prevention of the transmission of noise and vibration, appliances where the fastening means and mechanical connection are designed to permit removal for maintenance and repair, and data processing cables approved as a part of the data processing system.
Subpart S was based on the 1978 edition of the National Fire Protection Association (NFPA) standard 70E, Electrical Safety Requirements for Employee Workplaces , and the NFPA 70 Committee derived Part I of their document from the 1978 edition of the National Electrical Code (NEC).
In the 1978 NEC, 400-7 is identical to 1910.305(g)(1)(i) and 400-8 to 1910.305(g)(1)(iii). There is no definition for "flexible cord" or "extension cord"per se, as is the case with the OSH standards, but in the 1978 National Electrical Code Handbook there is a paragraph stating: "The flexible cords and cables referred to in this article are the ones that are attached to appliances and similar equipment. The reference is not to extension cords. See Article 305 [Temporary Wiring] for the applicable provisions covering the use of extension cords." The "uses permitted" in 400-7 and consequently in 39 CFR 1910.305(g)(1)(i) were not initially intended to address the use of extension cords.
In 1984, 400-7 was amended to add "(10) connection of moving parts; or (11) temporary wiring as permitted in Sections 305-2(b) and 305-2(c)", with the original nine uses remaining unchanged. The explanatory note also changed to read: "The flexible cords and cables referred to in this article are not limited to use with portable equipment. However, they are not permitted to be used as a substitute for the fixed wiring of a structure or where concealed behind building walls, ceilings, or floors. See Section 400-8. Also see Section 240-4 [Overcurrent Protection] Exception Number 3 and Article 305 for provisions covering extension cords." The last line of this note was changed again in the 1993 handbook: "Also see Article 305 for the requirement for the use of extension cords as temporary wiring", and remains unchanged in the 1999 Handbook.
Flexible cords are specifically excluded as a wiring method under the Code, by being placed in Chapter 4 (Equipment for General Use) as opposed to Chapter 3 (Wiring Methods and Materials). However, the implied definition of "wiring" are the conductors which carry electricity from the premises supply point (the service entrance) to the various outlets. Since the attachment plug of each appliance's power supply cord must by 29 CFR 1910.305(g)(1)(ii) be attached to an approved receptacle outlet, the use of an extension cord between the permanent outlet and the appliance's attachment plug means that the extension cord is either being used as an extension of the power supply cord, or as an extension of the permanent wiring of the building. If the cord connector on the extension cord is considered an approved receptacle outlet, the cord itself is being used as wiring. If not, then the appliance cannot be powered from it. It is reasonable to conclude that an extension cord is therefore being utilized as the wiring of a structure.
400-8 - and 1910.305(g)(1)(iii) - prohibit the use of flexible cords as permanent wiring methods. The North Carolina State Building Code, Volume V - Fire Prevention, specifically prohibits the use of extension cords (by name) from use as a substitute for permanent wiring. Use of flexible cords - including extension cords - as temporary wiring is specifically regulated by 29 CFR 1910.305(b) and NEC Article 305.
Both NEC-1978 305-1 and 29 CFR 1910.305(a)(2) limit the uses of temporary wiring to: "during the period of construction, remodeling, maintenance, repair, or demolition of buildings, structures, equipment, or similar activities", which are not activities in which employees of the Department of Labor engage. Use is also approved for a specific period of ninety (90) days for Christmas lighting and similar purposes. The 1999 Code extends acceptable uses to include emergencies, tests, and developmental work. If an extension cord is not in use for one of the purposes above, it is therefore in use as the permanent wiring of the structure, which is prohibited by the regulations. In 1998, NCOSH cited 29 CFR 1910.305(g)(1)(iii) 396 times, 50 of which were serious citations.
On October 30, 1996 in his then-role of NCOSH Safety Compliance Officer, the Safety and Health Director contacted via telephone Mr. Brian Baker, Project Engineer for Underwriters Laboratory (UL), who stated that UL considers extension cords to be temporary wiring and test them as such, and that the outer sheath of an extension cord is not tested by UL to withstand all damage it could be subjected to when used as a permanent installation.
In U.S. OSHA's training Fact Sheet 14, available on the Internet, the use of extension cords is identified as a hazard as follows:
"Flexible cord used in violation of this standard is likely to be damaged by activities in the area; by door or window edges; by staples or fastening; by abrasions from adjacent materials; or simply by aging. If the conductors become partially exposed over a period of time, there will be danger of shocks, burns or fire."
On May 18-22, 1992, NCOSH provided Electrical Safety Standards to its inspectors, prepared by TMK and Company. On page 11 of Fact Sheet 4 in the material distributed from that class, the following statement is read:
"There is usually not much question about use of the short length of cord which is furnished as part of an approved appliance or tool; there is usually no question about an extension cord used temporarily to permit use of the appliance or took in its intended manner at some distance from a fixed outlet; but there are questions when the usage is not obviously temporary, and when the cord is extended to some distant outlet in order to avoid providing a fixed outlet where needed. For example, a 50 foot extension cord used with an electric drill for maintenance purposes would usually not be a violation, but a 20-foot extension cord used with an electric typewriter or a production machine usually would be a violation. The use of the extension cord in the latter case would increase the hazard unnecessarily, because the cord could be eliminated if a fixed outlet were installed close to the point of use."
Use of extension cords as a substitute for the fixed wiring of a system is also recognized as a fire hazard. The North Carolina State Building Code, Volume V-Fire Prevention, states in 703.1: "Extension cords shall not be used as a substitute for permanent wiring." The seventh edition of the NFPA Inspection Manual lists the use of extension cords as a fire hazard as follows: "There are a number of several unsafe practices involving flexible cords that may result in fires. Among these are using them in the place of fixed wiring. Extension cords should be used only to connect portable equipment that is being used temporarily, not as part of the permanent wiring of a building." A perusal of Internet safety sites provided a strong recognition of the use of extension cords to supply ongoing power in lieu of a proper outlet as a hazard, of which the Massachusetts Institute of Technology (MIT) page is a representative: "The NEC standards may be summed up in a general way by saying that the use of an extension cord represents a conflict with the code because it serves as a substitute for a receptacle that should be located near the appliance or equipment." Several firesafety sites also address this issue, as did product pages for extension cord manufacturers (most of these merely repeated the requirement of 1910.305(g)(1)(iii)/NFPA 400-8(1) without further comment).
Power Strips
For the purpose of this discussion, power strip shall mean an electrical apparatus consisting of a strip containing one or more receptacles protected by a circuit breaker or fuse incorporated into its design, and powered by a flexible cord of a type listed in Table 400-4 of the NEC-1999.
Power strips are specifically addressed in a U.S. OSHA letter of interpretation dated June 11, 1993, as follows:
"'Power strips' as mentioned in your letter or 'surge/noise protective strips' as termed in the literature you sent as enclosures are generally referred to as temporary power taps. Temporary power taps that incorporate switches, indicator lights, filters for electromagnetic interference, fuses, varsitors, or other overcurrent mechanisms in their design could be devices for transient voltage surge suppression of equipment. Transient voltage surge suppressors when used to preserve the components of the equipment listed in your letter (computer, printer, fax, miscellaneous appliances and analytical instruments) could be considered a device as defined in 29 CFR 1910.399:
'Device. A unit of an electrical system which is intended to carry but not utilize electric energy.'
"If the temporary power taps are being used to provide transient voltage surge suppression, then these devices would meet the OSHA standards. If the temporary power taps are being used solely as wiring to provide extra or more convenient outlets, then this is a violation of 29 CFR 1910.305(g)(1)(iii)(A)...."
In other words, the purpose of the power strip is to protect equipment from unexpected surges in the voltage which could damage or destroy such equipment, and not to merely extend the flow of electrical energy to reach the equipment at a convenient location, which is the function of an extension cord. This makes the power strip a "device" or appliance, as opposed to "wiring." This removes them from the scope of 29 CFR 1910.305(g), Articles 305 and 400 of the National Electrical Code, and Chapter 8 of the North Carolina State Building Code. The determination, however, is based on why the strips are really being used. Computers, printers, faxes, and similar office equipment require protection from sudden and unexpected peaks and valleys in the power supply, and the use of power strips is justified. Radios, coffee pots, and similar equipment do not, and power strips are not justified to supply power to them.
Power strips themselves do not require transient voltage surge suppression, prohibiting one power strip from being plugged into another to create a "daisy chain."
Temporary Use
There are conditions where it will be necessary to supply power to a piece of portable equipment at a location where there is no available outlet within working distance, but which is infeasible to install a fixed outlet due to the short amount of time the equipment will be needed. In the Electrical Safety Standards Training booklet, William S. Watkins, P.E. suggests that the proper use of extension cords is for "temporary use" as opposed to temporary wiring. He defines the difference as: "Temporary wiring is secured from a fixed source to fixed outlets. Temporary use applies to extension cords which are not secured to the structure but are carried from place to place with the appliances they serve." Although there is no reference or allowance for "temporary use" in the standard or Code, it is obviously not the intent of the OSH standards to prohibit the complete use of extension cords for any purpose other than temporary wiring, since 29 CFR 1910.334(a)(2) addresses the use of extension cords with portable electric equipment in general industry businesses. Also, the reference to the 50 foot extension cord used with a portable drill referenced above lends credence to this determination.
Volume V of the North Carolina State Building Code does use the term "temporary use", and gives the following requirements for conditions of use:
"Extension cords are permitted only with portable appliances or fixtures. While in immediate use:
1. Each extension cord shall be plugged directly into an approved receptacle and shall, except for approved multiplying extension cords, serve only one appliance or fixture.
2. The current capacity of the cord shall not be less than the rated capacity of the appliance or fixture.
3. The extension cord shall be maintained in good condition without splices, deterioration, or damage.
4. The extension cord shall be of the grounding type when servicing grounded appliances or fixtures."
However, there is no definition or reference in the standard or either Code for "temporary." Based on the activities which can be reasonably anticipated to occur from the mission and activities of the Department which will require the temporary use of an extension cord, it is reasonable to conclude that such power only need be supplied while the equipment is actively in use or awaiting use (such as during a lunch break). Therefore, there should be no need for an extension cord to remain connected for greater than one workday.
Employees who utilize an extension cord under these circumstances will be responsible for complying with the requirements of 29 CFR 1910.334(a)(2)(i) and (ii). This means they must visually inspect the cord prior to its installation, to ensure that no damage - such as loose parts, missing or damaged blades or pins, or damage to the outer sheath - has occurred, and to immediately remove the cord from service if any damage is observed.
16 AWG stranded extension cords have an ampacity rating higher than 15 amps, which is the rating for standard outlets. The current requirements for the types of equipment most likely to be used by Department employees - computers, laptops, projectors, etc. - should be much less than the ampacity rating for the outlet or cord. Because of the requirement of 29 CFR 1910.304(f)(4), equipment with a grounding conductor must maintain continuity of the conductor; therefore, the minimum extension cord which should be used by the Department is 16 AWG three-wire, portable and suitable for hard usage.
Conclusions
1. Permanently wired outlets shall be provided wherever there is a need for electrical connection, and the power supply cord of electrical tools, appliances, and equipment shall be connected directly to that outlet via the attachment plug.
2. Power strips as defined in the discussion may be installed for permanent use to provide transient voltage surge protection to tools, appliances, and equipment requiring such protection. Strips shall be powered by connection directly to a permanent outlet.
3. Extension cords shall not remain connected to an outlet for any length of time greater than one workday.
4. Extension cords shall be inspected prior to each use by the employee who will use it, and shall be removed from service and not used if any sign of damage is evident.
5. The Department shall only purchase extension cords which are three-wire, 16 AWG or greater, single-outlet, and polarized.

This page last updated on August 31, 2004.

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