Double-insulated sewing machines and grounding

February 19, 1986

Mr. Neal A. Iund
Chief Mechanic
Bernina Sewing Machine Co., Inc.
[Recipient address omitted]
Subject: Double Insulated vs. Electrically Grounded Sewing Machines for School Use
Dear Mr. Iund:

Although many schools, municipal governments, and public sector employers utilize OSHA's regulations to establish minimum acceptable standards, we do not enforce our standards in these work situations.

It has consistently been the policy of this Agency not to approve specific types or brands of equipment. Neither do we accept, nor in fact reject, products by brand name except in the most unusual circumstances.

It is, however, generally recognized that within the scope of THE NATIONAL ELECTRIC CODE NFPA No. 70-1978, Article 250-45(d) Exception No. 2, and OSHA General Industry Standards 29 CFR 1910.304(f)(5)(v)(c)(8), double insulation is an effective means of protecting against the hazards of electrical shock when "the normally non-energied portions of the equipment become energized through improper use or malfunction". If this is the case with regard to BERNINA SEWING MACHINE, then you will have met the requirements that the equipment be "effectively grounded".

If you are in doubt as to your compliance with the grounding requirements of NEC Article 250-45(d), I suggest you supply all pertinent design specifications and testing documentation to:

Mr. Donald A. Shay, Director
Office of General Industry
Compliance Assistance
U. S. Department of Labor
Occupational Safety and Health
Administration
200 Constitution Avenue, N.W., Room N-3608
Washington DC 20210
(202) 523-8031

Sincerely,
BYRON R. CHADWICK
Regional Administrator - VIII
Occupational Safety and Health