OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at https://www.osha.gov.

December 9, 1986

                    Acting Regional Administrator

FROM:               JOHN B. MILES, JR., Director
                    Directorate of Field Operations

SUBJECT:            Possible Hazard in the Use of GFCI Worn on and
                    Employee's Belt

You have expressed concern about the use of a type of GFCI that is designed to be worn on an employee's belt. Your concern is that the employee may not be protected in the event that an extension cord into which the GFCI is plugged is not properly wired.

A review of the electrocution descriptions that OSHA submitted to the record for the ground-fault protection standard indicates that at least 11 of 41 deaths involved faults in extension cords rather than faults in the utilization equipment. Therefore, your concern seems well taken. As you noted in your memorandum, a portable GFCI does not protect against faults in the wiring supplying the device. For example, if the extension cord is miswired so that the ungrounded circuit conductor from the plug is connected to the equipment grounding lead to the receptacle, the placement of a portable GFCI at the receptacle end of the cord will not protect an employee who plugs a grounding-type tool into the GFCI. The faculty extension cord would cause the supply voltage to be impressed on the tool frame and could cause the electrocution of the employee.

Cord-connected GFCI/s warn that the device does not protect against some faults in the power supply cord and instruct the user to press the test button before plugging any equipment into it. If the GFCI does not trip, the user is warned not to use the circuit until it has been checked. This test will detect most hazardous faults in the wiring system up to the GFCI. However, it is not practical to expect the employee to press the test button on the GFCI every time he or she uses a different cord set as a source of supply.

Section 1926.404(b)(1)(ii) requires all 120-volt, single-phase, 15- and 20-ampere receptacle outlets on construction sites, which are not a part of the permanent wiring of the building or structure and which are in use by employees, to have GFCI's for personnel protection. As explained in the preamble that was published when the final rule was promulgated, portable GFCI's are acceptable if they are connected to the receptacle outlet in use. (See page 55702, second column, first paragraph, last sentence of the attached Federal Register notice.) If a group of extension cords is connected in series, the first receptacle outlet in the series must be connected directly to the GFCI, because the rule requires all covered receptacle outlets to have protection. In this way, all receptacle outlets in the group of cords would have GFCI protection. (Note: If an extension cord is plugged into a permanent receptacle outlet, the employer should be advised to install the portable GFCI at the permanent outlet, rather than at the receptacle outlet at the end of the cord set.)