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.

April 30, 2010

Letter # 20060601-7121

Re: Use of portable arc welding machines in inclement weather.

Question: Is it permissible to use a portable arc welding machine in inclement weather? If so, what steps need to be taken to prevent injury?


The OSHA standards that address the use of electrical welding equipment can be found at 29 CFR 1926.351 and 1926.354, as well as 1926.406(c). None of these standards prohibit the use of electrical (arc) welding equipment in inclement (wet) weather.

Sections 1926.351(a)-(c) detail the insulation and grounding requirements for arc welding equipment, all of which are designed to prevent employee electrocution through appropriate component capacity, equipment insulation, and grounding. Section 1926.351(d) addresses specific instructions the employer must give employees engaged in the use of electrical welding equipment, and section 1926.406(c) sets forth disconnecting means requirements for electrical welding equipment.

However, these standards do not address the possibility that current might be carried from an uncovered portable arc welder to an employee though moisture on the ground or in the air as precipitation, should the equipment covering, insulation, and grounding prove inadequate.

The General Duty Clause, also known as Section 5(a)(l) of the Occupational Safety and Health (OSH) Act, requires an employer to furnish to its employees:

employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees . . . .

The possibility of electrocution where an employee is working with or near electrical equipment that is in contact with moisture is a recognized hazard. Employers must therefore address the hazard of electrocution presented by use of electrical welding equipment in inclement weather, where the machine housing, insulation, and grounding would not prevent the transmission of electricity from the equipment to the worker through the moisture.

Employers might address this hazard by covering or enclosing the entire work area1 to prevent the electrical equipment from coming in contact with the precipitation, the provision of appropriate personal protective equipment, such as rubber gloves and boots intended for this purpose, or other methods of abatement as appropriate to the particular circumstance of a given task.

If you need further clarification on this subject, please contact us by fax at: U.S. Department of Labor, Directorate of Construction, Office of Construction Standards and Guidance, fax# 202-693-1689. You can also contact us by mail at the above office, Room N3468, 200 Constitution Avenue, N.W., Washington, D.C. 20210, although there will be a delay in our receiving correspondence by mail.


Bill Parsons, Acting Director
Directorate of Construction

1 Note, however, that enclosure of a work area during welding work may subject the employee to hazardous fumes, addressed by section 1926.353 of this standard. [back to text]