Frequently Asked Questions

Why don’t you call them explosion proof motors?

Legal terminology has over the years defined explosion proof as something which will withstand an explosion. We are concerned with preventing an explosion in the first place. For liability reasons we must be very careful in our choice of words.

Why doesn’t Empire Magnetics offer explosion proof stepper motors?

There are several reasons Empire Magnetics does not offer explosion proof stepper motors: 1) the legal costs associated with registering an explosion proof stepper motor are on the order of tens of thousands of dollars, and 2) once a motor is registered as explosion proof no changes can be made to the design.

Can you give me more information about system implementation?

For USA based customers, information can be obtained from the National Electric Code or from NFPA-496 - phone 800-344-3555. We apologize but we are not authorized to reproduce this copyrighted information. Furthermore, the party that supplies such information may be held liable for its contents.

The information is available from equivalent agencies worldwide. Here are a few of the international agencies we are aware of:

National Fire Protection Association, Battery March park, Quincy, MA 02269

Factory Mutual Research Corporation, 1151 Boston-Providence Turnpike, Norwood MA

PH: 617-762-4300

Underwriters’ Laboratories Inc., 333 Pfingsten Road, Northbrook, ILL 60062

PH: 312-272-8800

In other countries some of the appropriate agencies are:

British Approvals Service for Electrical Equipment in Flammable Atmospheres, Health and Safety Executive, Harpur Hill, Buxton, Derbyshire, England, SK179JN

PH: 0298-6211

British Electrical and Allied Manufacturers’ Association Committee for Electrical Equipment for use in Flammable Atmospheres, Leicester House, 8 Leicester Street, London England, WC2H 7BN

PH: 01-427-0678

British Standards Institution, Head Office 2 Park Street, London England , WlA 2 BS

PH: 041-629-9000

BSI Sales
Office, British Standards Institution, Linford Wood, Milton Keynes, Buckinghamshire England, MK14 6LE

PH: 0908-320066

Berggewerkschaftliche Versuchsstrecke, Beylingstrassee 65, 4600 Dortmund-Derne, West Germany

PH: 0231-2491-0

European Committee for Electrotechnical Standardisation, Secretariat General, Rue Brederode, 2 boite no. 5, B-1000 Brussels, Belgium

Cebtre d’Etudes et Recherches des Charbonnage de France, Laboratoire de Verneuil en Halatte, BP No. 27, 60103 Creil, France

PH: 4-455-3500

Centro Elettrotecnico Speriementale Italiano, Via Rubattino 54, Milano, Italy

PH: 02-392-2125

Canadian Standards Association, 178 Rexdale Boulevard, Rexdale, Ontario Canada M9W 1R3

PH: 416-744-4145

British Standards Institution, BSI/CSA Agency, Quality Assurance Services, P. O. Box 375, Milton Keynes, Buckinghamshire, MK14 6LO

PH: 0908-315555

Danmarks Elektriske Material Kontrol, Lyskoer 8, 2730 Herlev, Denmark,

PH: 02-947266

GAMBICA Association Ltd.
Association for instrumentation, control and automation industry in UK, Leicester House, 8 Leicester Street, London , WC2H 7BN

PH: 01-437-0678

International Electrotechnical Commission, Bureau Centrale de la Commission Electrotechnique, International, 1 rue de Varembe, Geneva, Switzerland

La Dirction de Paturages de L’Institut, National des Industries Extractives, Rue Grande 60, 7260 Paturages, Belgium


Institute of Petroleum Great Britain, 61 New Cavendish Street, London England

PH: 01-636-1004

Laboratoire Central des Industries Electrique, 33 Avenue de General Leclerc, 92260 Fontenay-aux-Roses, France

PH: 645-2184

Laboratorio Official J> M. Madariaga, Alenza, 1 y 2- Madrid 3, Spain

PH: 442-1987

Physikalisch-Technische Bundesanstalt, Bundesallee 100, D-3300 Braunschweig, West Germany

PH: 0531-592-2757

Research Institute of Industrial Safety of the Ministry of Labour, Technical Institution of Industrial Safety, 35-4, 5-Chome Schiba, Minatoku Tokyo Japan

Standards Association of Australia, Standards House, P. O. Box 458, 80 arthur Street, North Sydney Australia, NSW 2060

PH: 929-6022

Are the purged and pressurized motors explosion proof?

No. The term "explosion proof" means that the motor is capable of withstanding and containing an internal explosion. The concept of the purged and pressurized motor is to eliminate the explosion risk by keeping the hazardous materials outside the motor. Empire Magnetics’ purged and pressurized motors are designed to work within a system that meets the National Fire Protection Agency (NFPA) requirements for class I, II, and/or III environments (see NFPA 496, "Purged and Pressurized Enclosures for Electrical Equipment in Hazardous Locations").

Does Empire Magnetics offer engineering assistance for designing the system?

No, for legal reasons cannot offer engineering assistance other than to recommend consulting the NFPA 496 guideline.

Where can I find pressure switches and temperature monitors for my system?

Pressure switches and temperature monitors are available from Omega (800 826 6342).