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NEMA OS 3-2016 Selection and Installation Guidelines for Electrical Outlet Boxes, 2016
- Foreword
- Introduction
- Section 1 Product Selection [Go to Page]
- 1.1 General
- Figure 1 Outlet Box Selection Criteria
- 1.2 Select the Outlet Box for the Type of Wiring System Used [Go to Page]
- 1.2.1 Connection to the Wiring System
- 1.2.2 Wiring Systems Employing Tubing or Conduit
- 1.2.3 Wiring Systems Employing Metal-Jacketed or Nonmetallic-Sheathed Cable
- 1.2.4 Grounding
- 1.3 Select the Box Based on Contents and Function after Installation [Go to Page]
- 1.3.1 Internal Volume Capacity of Boxes
- 1.3.2 Junction and Pull Boxes
- 1.3.3 Outlet and Device Boxes—Mounting of Wiring Devices [Go to Page]
- 1.3.3.1 Device Boxes for Flush Mounting
- 1.3.3.2 Device Boxes for Surface Mounting
- 1.3.3.3 Outlet Boxes for Flush Mounting
- 1.3.3.4 Outlet Boxes for Surface Mounting
- 1.3.3.5 FS and FD Boxes
- 1.3.4 Outlet and Device Boxes—Support of Luminaires, Ceiling-Suspended Fans, and Other Products [Go to Page]
- 1.3.4.1 Outlet and Device Boxes Intended for Support of Luminaires and Other Products [Go to Page]
- 1.3.4.1.1 For Products Weighing 2.7 kg (6 lbs.) or Less
- 1.3.4.1.2 For Products Weighing More Than 2.7 kg (6 lbs.), up to 22 kg (49 lbs.)
- 1.3.4.1.3 For Products Weighing More Than 2.7 kg (6 lbs.), up to 23 kg (50 lbs.)—New Work Only
- 1.3.4.1.4 For Products Weighing Greater Than 23 kg (50 lbs.) in or on Ceilings—New Work Only
- 1.3.4.2 Outlet Boxes Intended to Support Ceiling-Suspended Fans
- 1.3.5 Outlet and Device Boxes with Fire-Resistive Ratings (Hours)
- 1.3.6 Boxes for High- and Low-Voltage Wiring Circuits (Class 1, Class 2, and Class 3 Circuits) [Go to Page]
- 1.3.6.1 Low-Voltage Wiring Circuits (Class 2 and Class 3 Circuits)
- 1.3.6.2 High- and Low-Voltage Wiring Systems Installed Together
- 1.3.6.3 Voltage between Adjacent Devices
- 1.4 Select the Outlet Box for the Intended Installation Location [Go to Page]
- 1.4.1 General
- 1.4.2 Boxes for Installation in or on Walls or Ceilings [Go to Page]
- 1.4.2.1 Surface Mounting Outlet Boxes (Indoors and Outdoors)
- 1.4.2.2 Flush Mounting Outlet and Device Boxes in Hollow Walls or Ceilings
- 1.4.2.3 Flush Mounting Boxes in Concrete and Masonry Walls and Ceilings
- 1.4.2.4 General-Purpose Boxes Installed above Suspended Ceilings
- 1.4.3 Boxes for Installation in Floors [Go to Page]
- 1.4.3.1 General
- 1.4.3.2 Concrete Floors
- 1.4.3.3 Through-Floor Penetrations
- 1.4.3.4 Hollow Floors
- 1.4.3.5 Raised Floors
- 1.4.3.6 Floor Box Covers
- 1.4.4 Boxes for Other Locations [Go to Page]
- 1.4.4.1 Pendant Box Assemblies
- 1.4.4.2 Pedestal Box Assemblies
- 1.4.4.3 Plenum Boxes
- 1.4.4.4 Swimming Pool Boxes
- 1.4.4.5 Boxes and Covers for Use in Wet and Damp Locations and Adverse Environments
- 1.4.4.6 Boxes for Direct Burial in Earth
- 1.4.4.7 Boxes in or on Partitions
- 1.4.4.8 Boxes in or on Furniture
- 1.4.4.9 Boxes in Surface Raceway Systems
- 1.4.5 Outlet and Device Boxes for Use in Fire-Resistive Construction [Go to Page]
- 1.4.5.1 General
- 1.4.5.2 Metallic Boxes
- 1.4.5.3 Nonmetallic Boxes
- 1.4.5.4 Poke-Through Floor Fittings
- 1.4.6 Special Use Boxes
- 1.4.7 Covers and Cover Plates for Dry Locations
- 1.4.8 Extension Rings and Box Extenders [Go to Page]
- Flush Mount—New Work Flush Mount—Old Work Flush Mount—Ceiling
- Surface Mount—Exposed Surface Mount—Protected Pendant Mount
- Square Box with Raised Cover (Additional Support Necessary)
- Masonry Box Old Work—Ceiling
- Ceiling Installation
- Wall Installation
- Device Box
- Outlet Box
- Device Box
- Outlet Box
- Section 2 Product Installation [Go to Page]
- 2.1 Introduction [Go to Page]
- 2.1.1 Storage and Preparation for Installation
- 2.1.2 Coordinating Trades after Boxes Are Mounted
- 2.2 Fire-Resistive Construction [Go to Page]
- 2.2.1 Metallic Boxes
- 2.2.2 Nonmetallic Boxes [Go to Page]
- Class * hr, F, W and/or C
- 2.2.3 Poke-Through Floor Fittings
- 2.3 Mounting and Securing of Electrical Boxes [Go to Page]
- 2.3.1 General
- 2.3.2 Surface Mounting on Walls or Ceilings
- 2.3.3 Boxes Supported by Raceways
- 2.3.4 Flush Mounting in Walls and Ceilings [Go to Page]
- 2.3.4.1 New Work Installations
- 2.3.4.2 Old Work Installations
- 2.3.5 Pendant Mounting
- 2.3.6 Pedestal Mounting
- 2.3.7 Masonry Wall Mounting
- 2.3.8 Floor Box Mounting [Go to Page]
- 2.3.8.1 Hollow Floors
- 2.3.8.2 Concrete Floors
- 2.3.9 Poke-Through Floor Fitting—Mounting
- 2.3.10 Other Boxes [Go to Page]
- 2.3.10.1 Swimming Pool Junction Boxes
- 2.3.10.2 Boxes for Use in Wet and Damp Locations and Adverse Environments
- 2.3.10.3 Boxes for Direct Burial in Earth
- 2.3.10.4 Boxes in or on Partitions
- 2.3.10.5 Boxes in or on Furniture or Equipment
- 2.3.10.6 Boxes in Surface Raceway Systems
- 2.3.10.7 Special Use Boxes
- 2.4 Connection to Wiring Systems [Go to Page]
- 2.4.1 General
- 2.4.2 Connection to Conduit Entries [Go to Page]
- 2.4.2.1.1 Where the conduit entry has threads tapped all the way through (no integral bushing), care must be taken to ensure that at least 3-1/2 threads of the conduit or threaded fitting are fully engaged with the threads of the conduit entry when wr...
- Integral Bushing
- Thread Engagement
- 2.4.2.2 Unthreaded Entries for Unthreaded Conduit or Tubing [Go to Page]
- 2.4.2.2.1 Knockouts
- 2.4.2.2.2 Unthreaded Sockets (Hubs)
- 2.4.2.2.3 Floor Boxes in Concrete Floors
- 2.4.3 Connection to Cable Entries [Go to Page]
- 2.4.3.1 General
- 2.4.3.2 Metallic Boxes [Go to Page]
- 2.4.3.2.1 General
- 2.4.3.2.2 Nonmetallic-Sheathed Cable
- 2.4.3.2.3 Metal-Jacketed Cables
- 2.4.3.2.4 Flexible Metal Conduit or Tubing
- 2.4.3.2.5 Screw Torque
- 2.4.3.3 Nonmetallic Boxes [Go to Page]
- 2.4.3.3.1 Nonmetallic-Sheathed Cable
- 2.4.4 Connection to High- and Low-Voltage Wiring Circuits
- 2.5 Completing the Installation [Go to Page]
- 2.5.1 Introduction
- 2.5.2 Grounding and Bonding [Go to Page]
- 2.5.2.1 Metallic Boxes
- 2.5.2.2 Devices Installed in Surface-Mounted Metallic Boxes, e.g., Device (Utility) Boxes; FS and FD Boxes; and Square, Round, and Octagon Boxes
- 2.5.2.3 Devices Installed in Flush Metallic Boxes
- 2.5.2.4 Common Grounding/Bonding Errors
- 2.5.3 Installation of Wiring Devices [Go to Page]
- 2.5.3.1 General
- 2.5.3.2 Voltage between Adjacent Devices
- 2.5.3.3 Boxes Intended to Support Luminaires, Ceiling-Suspended Fans, and Other Products [Go to Page]
- 2.5.3.3.1 Boxes Intended to Support Luminaires
- 2.5.3.3.2 Boxes Intended to Support Ceiling-Suspended Fans
- 2.5.3.4 Boxes for Fire-Resistive Construction
- 2.5.3.5 Floor Boxes
- 2.5.3.6 Poke-Through Floor Fittings
- 2.5.4 Flush-Device Boxes: Coordination with Finished Wall Surface Installation
- 2.5.5 Installation of the Cover and/or Cover Plate [Go to Page]
- 2.5.5.1 Damp or Wet Locations
- 2.5.5.2 Dry Locations
- 2.6 Verification of Installation [Go to Page]
