Recommended Practice for Design, Installation, and Maintenance of Electrical Systems for Fixed and Floating Offshore Petroleum Facilities for Unclassified and Class I, Zone 0, Zone 1, and Zone 2 Locations

API RECOMMENDED PRACTICE 14FZ SECOND EDITION, MAY 2013

REAFFIRMED, APRIL 2020

Special Notes

API publications necessarily address problems of a general nature. With respect to particular circumstances, local, state, and federal laws and regulations should be reviewed.

Neither API nor any of API's employees, subcontractors, consultants, committees, or other assignees make any warranty or representation, either express or implied, with respect to the accuracy, completeness, or usefulness of the information contained herein, or assume any liability or responsibility for any use, or the results of such use, of any information or process disclosed in this publication. Neither API nor any of API's employees, subcontractors, consultants, or other assignees represent that use of this publication would not infringe upon privately owned rights.

API publications may be used by anyone desiring to do so. Every effort has been made by the Institute to assure the accuracy and reliability of the data contained in them; however, the Institute makes no representation, warranty, or guarantee in connection with this publication and hereby expressly disclaims any liability or responsibility for loss or damage resulting from its use or for the violation of any authorities having jurisdiction with which this publication may conflict.

API publications are published to facilitate the broad availability of proven, sound engineering and operating practices. These publications are not intended to obviate the need for applying sound engineering judgment regarding when and where these publications should be utilized. The formulation and publication of API publications is not intended in any way to inhibit anyone from using any other practices.

Any manufacturer marking equipment or materials in conformance with the marking requirements of an API standard is solely responsible for complying with all the applicable requirements of that standard. API does not represent, warrant, or guarantee that such products do in fact conform to the applicable API standard.

Classified areas may vary depending on the location, conditions, equipment, and substances involved in any given situation. Users of this Recommended Practice should consult with the appropriate authorities having jurisdiction.

Users of this Recommended Practice should not rely exclusively on the information contained in this document. Sound business, scientific, engineering, and safety judgment should be used in employing the information contained herein.

API is not undertaking to meet the duties of employers, manufacturers, or suppliers to warn and properly train and equip their employees, and others exposed, concerning health and safety risks and precautions, nor undertaking their obligations to comply with authorities having jurisdiction.

Work sites and equipment operations may differ. Users are solely responsible for assessing their specific equipment and premises in determining the appropriateness of applying the Recommended Practice . At all times users should employ sound business, scientific, engineering, and judgment safety when using this Recommended Practice.

All rights reserved. No part of this work may be reproduced, translated, stored in a retrieval system, or transmitted by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher. Contact the Publisher, API Publishing Services, 1220 L Street, NW, Washington, DC 20005.

Copyright © 2012 American Petroleum Institute

Foreword

Nothing contained in any API publication is to be construed as granting any right, by implication or otherwise, for the manufacture, sale, or use of any method, apparatus, or product covered by letters patent. Neither should anything contained in the publication be construed as insuring anyone against liability for infringement of letters patent.

Shall: As used in a standard, “shall” denotes a minimum requirement in order to conform to the specification.

Should: As used in a standard, “should” denotes a recommendation or that which is advised but not required in order to conform to the specification.

This document was produced under API standardization procedures that ensure appropriate notification and participation in the developmental process and is designated as an API standard. Questions concerning the interpretation of the content of this publication or comments and questions concerning the procedures under which this publication was developed should be directed in writing to the Director of Standards, American Petroleum Institute, 1220 L Street, NW, Washington, DC 20005. Requests for permission to reproduce or translate all or any part of the material published herein should also be addressed to the director.

Generally, API standards are reviewed and revised, reaffirmed, or withdrawn at least every five years. A one-time extension of up to two years may be added to this review cycle. Status of the publication can be ascertained from the API Standards Department, telephone (202) 682-8000. A catalog of API publications and materials is published annually by API, 1220 L Street, NW, Washington, DC 20005.

Suggested revisions are invited and should be submitted to the Standards Department, API, 1220 L Street, NW, Washington, DC 20005, standards@api.org.

iii

1. General 1

   1. Scope 1

   2. Applicability of National Electrical Code 2

2. Normative References 2

   1. General 2

   2. Industry Codes, Guides, and Standards 2

   3. Government Codes, Rules, and Regulations 11

   4. Code of Federal Regulations (CFR) 11

   5. Classification Society Rules and Regulations 12

3. Acronyms, Terms, and Definitions 12

   1. Acronyms 12

   2. Definitions, Abbreviated 14

   3. Definitions Specific to Floating Facilities 29

4. Electrical Equipment for Hazardous (Classified) Locations 30

   1. General 30

   2. High-temperature Devices 31

   3. Protection Techniques Related To Equipment Suitable for use in Locations Classified as

      Division 1 or Division 2 31

   4. Protection Techniques Related to Equipment Approved for Zone 0, Zone 1, or Zone 2 Locations 34

   5. General Purpose Equipment 36

   6. Listing, Marking and Documentation 37

   7. Gas Group 38

5. Electric Power Generating Stations 38

   1. General 38

   2. Prime Movers 38

   3. Generators 42

   4. Generator Station Packaging Considerations 48

   5. Switchboards 48

   6. Special Requirements for Floating Facilities 51

6. Electrical Distribution Systems 54

   1. Scope 54

   2. Voltage Level Selection 54

   3. Conductor Selection 55

   4. Wiring Methods for Hazardous (classified) Locations 63

   5. Wiring Methods for Unclassified Locations 67

   6. Wiring Methods for Drilling and Workover Rigs 68

   7. General Wiring Considerations 68

   8. Conduit and Cable Seals and Sealing Methods 72

   9. Circuit Protection. 85

   10. Grounding 87

   11. Electrical Enclosures 89

   12. Working Space About Electrical Equipment and Means of Access 93

   13. Additional Requirements for Floating Facilities 95

7. Electric Motors 96

   1. General 96

   2. Selection 96

      
      

   3. Motor Space Heaters 98

   4. Motor Control 98

8. Transformers 100

   1. General 100

   2. Selection 101

   3. Installation 102

   4. Connections 102

   5. Protection 103

9. Lighting 104

   1. General 104

   2. Lighting Levels 104

   3. Fixture Selection and Installation 106

   4. Standby Lighting 109

   5. Lighting for Helicopter Operations 110

10. Battery-powered DC Supply Systems 111

    1. General 111

    2. Specific Applications 111

    3. Batteries 112

    4. Battery Chargers 115

    5. Uninterruptible Power Supply (UPS) Systems 117

11. Special Systems 119

    1. Electrical Platform Safety Control Systems 119

    2. Gas Detection Systems 121

    3. Fire Detection Systems 123

    4. Aids-to-Navigation Equipment 124

    5. Communications Equipment 126

    6. Heat Trace Systems 126

    7. Fire Pumps 126

    8. Adjustable Speed Drives (Variable Frequency Drives) 127

    9. Submarine Cables 134

    10. Electric Oil-immersion Heaters 134

    11. Electric Power-operated Boat Winches for Survival Craft 134

    12. Electric Power-operated Water-tight Doors 134

    13. Hull Mechanical Systems Controls 135

    14. Cargo Tanks on Floating Facilities 136

    15. Cargo Handling Rooms on Floating Facilities 136

    16. General Alarm System 136

    17. Cathodic Protection 139

    18. Subsea Electrical Systems 141

12. Special Considerations 143

    1. Construction Practices 143

    2. Electronic Instrumentation 144

    3. Electrical Tools 145

    4. Electrical Appliances 145

    5. Extension Cords 145

    6. Electrical Equipment Buildings 146

       
       

    7. Laboratory Buildings 146

    8. Signs 146

    9. Lockout and Tagout Procedures 146

    10. Portable Electronic Devices 146

    11. Abandoned Raceways and Conductors 146

13. System Checkout 147

    1. General 147

    2. Generators and Motors 147

    3. Instrumentation and Control Circuits 147

14. Maintenance 147

15. Safety 148

Annex A (informative) Inspection Intervals 149

Annex B (informative) ABS Rules For Building and Classing Steel Vessels—1998, PART 4 151

Annex C (informative) USCG Requirements, 46 CFR, Subchapter J, 111.95 160

Annex D (informative) USCG Requirements, 46 CFR, Subchapter J, 111.97 162

Annex E (informative) USCG Requirements, 46 CFR, Subchapter J, Subpart 111.105 164

Annex F (informative) Electrical Inspection Checklist 176

Figures

1. Typical Class I, Zone 1 Electrical Installation Conduit System Utilizing Class I, Division I

   Equipment and Wiring Methods 73

2. Typical Class I, Zone 1 Electrical Installation Cable System Utilizing Class I, Division 1

   Equipment and Wiring Methods 74

3. Typical Class I, Division Zone 2 Electrical Installation Conduit or Cable System Utilizing

   Class I, Division 2 Equipment and Wiring Methods 75

4. Typical Class I, Zone 1 or Zone 2 Electrical Installation Conduit System Utilizing

   Class I, Zone 1 Equipment and Wiring Methods 76

5. Typical Class I, Zone 1 or Zone 2 Electrical Installation Cable System Utilizing Class I, Zone 1 Equipment and Wiring Methods 77

6. Typical Class I, Zone 2 Electrical Conduit or Cable Installation Utilizing Class I, Zone 2

   Equipment and Wiring Methods 78

7. Typical Class I, Zone 1 or Zone 2 Electrical Installation Conduit or Cable Connections to

   Flammable Fluid Process-Connected Nonarcing Devices with Single-Seal Diaphragms or Tubes 79

8. Typical Class I, Zone 1 or Zone 2 Electrical Installation Conduit and Cable Connections to

   Flammable Fluid Process-Connected Nonarcing Devices with Multiple-Seal Diaphragms or Tubes. . . 80

9. Typical Class I, Zone 1 or Zone 2 Electrical Installation Conduit or Cable Connections to Flammable Fluid Process-Connected Nonarcing Devices with Multiple-Seal Diaphragms or Tubes 81

10. Typical Class I, Zone 1 or Zone 2 Electrical Installation Placement of Drain Seals 82

11. Typical Speed Torque Curve for Variable Torque Load 129

12. Typical Speed Torque Curve for Constant Torque Load 130

13. Typical Speed Torque Curve for Constant Horsepower Load 130

14. Typical Speed Torque Characteristics for Impact-type Loads 131

4/5C.1 Limiting Curves for Loading 4-stroke Diesel Engines Step by Step from No-load to Rated

Power as Function of the Brake Mean Effective Pressure 157

Tables

1. Types of Protection Designation 36

2. Ampacities for Marine Shipboard Distribution, Control, and Signal Cables, 2000 Volts or Less, AC or DC, Copper Conductors, Single-banked (Single-layered), Maximum Current-carrying

   Capacity Based on 45 °C (113 °F) Ambient 56

   2A Allowable Ampacities of Insulated Nickel Coated Copper Conductors (27 % Nickel) Rated 0 Through 2000 Volts, 75 °C (140 °F), Not More Than Three Current-Carrying Conductors in

   Raceway, Cable Maximum Current-carrying Capacity Based on 45 °C (113 °F) Ambient 57

3. Ampacities for Marine Shipboard Single-conductor Distribution Cables, 2000 Volts or Less DC Only, Copper Conductors, Single-banked (Single-layered), Maximum Current-carrying

   Capacity Based on 45 °C (113 °F) Ambient 57

4. Ampacities for Three-conductor Medium Voltage Power Cable, 2001 Volts to 35 kV, Copper Conductor Single-banked (Single-layered), Maximum Current-carrying Capacity Based

   on 45 °C (113 °F) Ambient 59

5. Ampacities for Medium Voltage Power Cable, 2001 Volts to 35 kV, Copper Conductor,

   Single-conductor in Triplexed or Triangular Configuration, Maximum Current-carrying Capacity

   Based on 45 °C (113 °F) Ambient 60

6. Ampacities for Single-conductor Medium Voltage Power Cable, 2001 Volts to 35 kV, Copper Conductor Single-banked (Single-layered), Maximum Current-carrying Capacity Based

   on 45 °C (113 °F) Ambient, Shields Grounded on One End (Open-circuited Shields) 61

7. Wiring Methods for Hazardous (classified) Locations 63

8. Common Power and Control Cables Sizes and Configurations 72

9. Common Instrumentation Cable Sizes and Configurations 72

10. Circuit Protection Devices—Advantages and Disadvantages 86

11. NEMA Enclosures 90

12. Degree of Protection of Enclosures in Accordance with IEC 60529 92

13a Selection of IEC 60529 IP Rated Enclosures to Meet NEMA Requirements 94

13b Selection of NEMA Enclosures to Meet IP Designations 94

1. Working Clearances 95

2. NEMA Motor Starter Sizing 99

3. Minimum Recommended levels of Illumination for Efficient Visual Tasks 105

   16A Minimum Recommended Levels of Illumination for Hazard Recognition 105

4. Minimum Recommended Levels of Illumination for Safety 106

5. Comparison of Batteries by Cell Type. 114

6. Possible combination of Tones for Fixed Platforms 137

7. One Possible Combination of Tones for Floating Facilities 139

A.1 Inspection Intervals 149

Design, Installation, and Maintenance of Electrical Systems for Fixed and Floating Offshore Petroleum Facilities for Unclassified and Class I, Zone 0, Zone 1, and Zone 2 Locations

1. General

   
   

   1. Scope

      
      

      1. This document recommends minimum requirements and guidelines for the design, installation, and maintenance of electrical systems on fixed and floating petroleum facilities located offshore. For facilities classified as Division 1 or Division 2, reference API 14F. These facilities include drilling, producing and pipeline transportation facilities associated with oil and gas exploration and production. This recommended practice (RP) is not applicable to Mobile Offshore Drilling Units (MODUs) without production facilities. This document is intended to bring together in one place a brief description of basic desirable electrical practices for offshore electrical systems. The recommended practices contained herein recognize that special electrical considerations exist for offshore petroleum facilities. These include:

         
         

         1. inherent electrical shock possibility presented by the marine environment and steel decks;

            
            

         2. space limitations that require that equipment be installed in or near hazardous (classified) locations;

            
            

         3. corrosive marine environment;

            
            

         4. motion and buoyancy concerns associated with floating facilities.

         
         

      2. This RP applies to both permanent and temporary electrical installations. The guidelines presented herein should provide a high level of electrical safety when used in conjunction with well-defined area classifications. This RP emphasizes safe practices for hazardous (classified) locations on offshore petroleum facilities but does not include guidelines for classification of areas; for guidance on the classification of areas refer to API 505.

         
         

      3. Advantages of area classification using zones are as follows.

         
         

         1. Often, particularly for new installations and for installations that are subject to upgrade or revision, it is advantageous to classify locations as “Zones” in accordance with Article 505 of the NEC versus “Divisions” as per Article 500. These advantages may include reduced initial capital expenditures, enhanced safety, or facilities that are more easily and more economically maintained.

            
            

         2. In the Zone classification system, locations classified as Division 1 in the Division classification system can now be classified and further divided into Zone 0 and Zone 1 locations. Electrical equipment suitable for Zone 1 locations is not required to be suitable for locations where flammable gases and vapors may be present continuously or for long periods of time, i.e. Zone 0 locations. Thus, the protection techniques for equipment to be installed in Zone 1 locations can be less demanding than the protection techniques for equipment to be installed in Division 1 locations. This may result in more cost effective installations or equipment that is more easily maintained.

            
            

         3. Due to the application of increased safety (protection Type “e”) equipment, fewer field-installed sealing fittings are required for Zone 1 and Zone 2 equipment than for Division 1 and Division 2 equipment. Fewer field- installed sealing fittings reduce the chance for installation errors, enhancing safety. Much of the equipment approved for Zone 1 and Zone 2 uses plastics (versus metals), reducing corrosion, which can result in reducing maintenance costs and enhancing safety. Also, since the most hazardous locations (Zone 0 locations) are identified, such locations can be avoided for the installation of most electrical equipment. This also can enhance safety.

1