Hello

Welcome lekule blog

Hi, I`m Sostenes, Electrical Technician and PLC`S Programmer.
Everyday I`m exploring the world of Electrical to find better solution for Automation.
together in the world. #lekule86
Join us on

Electrical Boxes

In Article " Conduit Fittings and Supports ", I explained the following points:

  • Types of Conduit Fittings and Supports,
  • Notes for Conduit Supporting.


Today, I will explain The Types of Electrical Boxes as follows.



You can review the following articles in the same course for more information:







1- Functions of the Electrical Boxes
In any installation, the electrical boxes are used to fulfill the following requirements:

  1. The electrical boxes enclose the wire connection or cable splices.
  2. The electrical boxes shield wood building framing members or other adjacent flammable objects from electrical sparks should the wiring be defective.
  3. The electrical Boxes also protect people from accidental electrical shock and keep moisture and dust out of wire connections or splices.




2- Electrical Boxes Materials
Most electrical boxes are made from the following materials:

  1. Sheet steel and have a painted or galvanized finish,
  2. Cast iron,
  3. Aluminum,
  4. PVC, or
  5. Clear polycarbonate.




3- Where an electrical box is required in the wiring system?
Section 300.15 of the NEC contains specific requirements for where a box or conduit body is required in the wiring system. As can be seen, there is a general statement with several exceptions.

1- Box or Conduit Body
A box or conduit body complying with Article 314 is required to be installed at each conductor splice connection point, outlet, switch point, junction point, or pull point for the connection of conduit, electrical metallic tubing, surface raceway or other raceways.

2- Box Only
A box is required to be installed at each conductor splice connection point, outlet, switch point, junction point or pull point for the connection of Type MC cable, mineral-insulated, metal-sheathed cable, or other cables. A box shall be installed at the connection point between any such cable system and a raceway system.
Note:
  • Boxes should be installed only when needed. Too many boxes would introduce so much splicing of conductors that the likelihood of problems from improperly spliced conductors would increase.




4- General Rules for Boxes

  • All boxes must be large enough to provide for sufficient free space for all conductors that will be enclosed within them to prevent overcrowding and possible physical damage when the devices or splices are installed or completed.
  • No box is permitted to have an internal depth of less than 1/2 inch. A box that is intended to enclose flush devices is required to have an internal depth of not less than 15/16 inch.
  • In completed installations each box is required to have a cover, faceplate or fixture canopy.
  • Metal covers used with nonmetallic boxes are required to be grounded.
  • Boxes with supports are required in vertical raceways where the weight of the cable would place excessive strain on the conductor terminals. These conduit-support boxes are common in high rise buildings, where heavy feeder conductors are used.
  • Boxes are available with different numbers of knockouts (KOs) or pryouts (POs) to accommodate different arrangements for switch levers, control knobs, receptacle sockets, or other devices.
  • Because so many different manufacturers offer these electrical boxes, the reader is advised to consult the latest manufacturers’ catalogs for more details than can be given here.




5- Mounting of Electrical Boxes

  • Any type of box must be set flush in a wall or ceiling of wood or other combustible material. In this way, material that will burn is kept away from the wires in case of arcs or sparks in the box. If the box is set in a wall or ceiling of material that will not burn, the box may be recessed up to 1/4 inch.
  • At least 6 inches of conductor must be left at an outlet or switch box to connect fixtures or devices. This measurement is taken from the point where the conductor emerges from the conduit or cable sheath. Where the box opening is less than eight inches in any dimension, each conductor shall extend 3 inches outside the opening.





6- Types of Electrical Boxes
There are many types of boxes used in a conduit installation.  The application and site conditions determine the type of box used. The electrical boxes can be divided to:

  • The outlet boxes,
  • Device boxes,
  • Pull and junction boxes.

The following is a list of the more common boxes and a brief description of their intended use.

First: Outlet Boxes


The outlet boxes with the correct fittings be installed at the following locations:

  1. Each conductor splice point,
  2. Each outlet, switch point, or junction point,
  3. Each pull point for the connection of conduit and other raceways,
  4. Transitions from conduit to open cables.

  • A wide variety of standard metal and nonmetallic electrical or outlet boxes are available commercially for installing switches and receptacles, connecting lighting fixtures, and protecting splices. Only the most commonly used boxes and their features are discussed and illustrated in this course.
  • The type of enclosures used as outlet and device boxes for supporting, enclosing and securing wiring devices such as switches, receptacles or other equipment on the same yoke or strap are available in various sizes and shapes. These enclosures may be used in one, two, three or more gang types.


6.1 Rectangular outlet boxes





Rectangular outlet box
  • Rectangular outlet boxes are intended for installing a single switch or a duplex receptacle. Also called device boxes, they are normally mounted vertically in walls by fastening them to wall studs in new construction.
  • Rectangular outlet boxes can be ganged together with matching boxes to provide a single box with twice the volume. After removing the opposing removable sides of each box, they are fastened together with screws to form one rigid unit. Ganged boxes can accept two switches or two duplex receptacles with their associated wiring.

6.2 Octagonal Outlet Boxes





  • An octagon box often referred to as a “fixture box”, connects light fixtures.  Octagon boxes have cover plates to protect conductors when the box is used as a junction box. Table 314-16(a) lists the sizes of boxes with or without devices, but only #14 through #6 wires may be used. Octagon boxes are available in different sizes to accommodate cable clamps, fitting, and devices (switches or receptacles).


  • These boxes are conventionally measured diagonally, where their actual dimensions are 4 in., but they have nominal 4-in. dimensions when measured between their flat sides. They can be fastened to ceiling joists or studs with nails or screws, or can be supported by telescoping metal braces that extend to fit between adjacent joists. These boxes are frequently used to support luminaires if there are studs or hickeys in the box, on the box covers, or on cross straps.

Notes for fixture boxes:

  • Boxes for supporting lighting fixtures and ceiling paddle fans are available in the round and octagonal types.
  • Generally, device boxes are not acceptable for securing or supporting lighting fixtures. One of the reasons is that device boxes have 6-32 tapped screw holes and round or octagonal boxes have 8-32 tapped screw holes to support the weight of the lighting fixture.

6.3 Round Ceiling Pan Boxes



  • Round ceiling pan boxes with diameters of 3.25 in. have applications similar to those of octagonal boxes because they can be mounted on walls or ceilings to support light fixtures. Round boxes with depths of 0.5 in. have volumes of 4 in.3, and those with depths of 0.75 in. have volumes of 5.5 in.3. A choice of internal cable clamps is offered with these boxes, and they can accept round covers that fit both round and octagonal boxes.

6.4 Square Outlet Boxes





  • The square box measures four inches by four inches. They are large enough to gang two switches or two duplex receptacles in one box or to protect cable splices.
  •  It encloses switches, thermostats, timers and receptacles. They have more cubic-inch volume than octagon boxes and allow more conductors to be installed. They also have accessories such as plaster (mud) rings to mount fixtures or devices. It also functions as a junction box or pull box.
  • Where a square metal box is used, it may be used for the support of a fixture or device, depending on the type of raised cover used. These covers are often referred to as “plaster” or “mud” rings.
  • Square boxes are also normally mounted vertically in walls by nailing them to studs during original construction. A wide selection of cover plates is available for these boxes, with different cutouts to admit the toggles of strap-mounted switches or to expose both outlets of strap-mounted dual receptacles. Single switches or duplex receptacles can be installed in these boxes if an adapter cover plate with a centrally located cutout is used.


6.5 The Utility Box




  • The utility box or outlet box mounts on surfaces.  It is often referred to as a “handy box.”  The utility box encloses switches, receptacles, thermostats, or push button units.  The box is a minimum of 1.5 inches deep. Boxes must meet the minimum cubic inch capacity per number of conductors per Table 314-16(a) and Table 314-16(b) of Article 314 in the NEC.  Connect conduit to any one of the knockout holes in the box. This type of box is used for exposed work.








6.6 The Conduit Device Box




  • A conduit device box  installs in drywall.  The sides can be removed to enlarge it by attaching another box.  This is referred to as "ganging the boxes."  A conduit device box installs in offices and homes for switches and receptacles.

6.7 The masonry box




  • The masonry box is special conduit device boxes. The masonry box installs in concrete block and brick walls.  Available in various sizes, the masonry box does not enlarge.


6.8 The weatherproof box




  • The weatherproof box is special conduit device boxes and used outside and in damp or wet areas.  The weatherproof box is made of heavy cast metal and has a threaded hub to connect to conduit.  

Share this:

ABOUTME

Hi all. This is deepak from Bthemez. We're providing content for Bold site and we’ve been in internet, social media and affiliate for too long time and its my profession. We are web designer & developer living India! What can I say, we are the best..

Post a Comment
My photo

Hi, I`m Sostenes, Electrical Technician and PLC`S Programmer.
Everyday I`m exploring the world of Electrical to find better solution for Automation. I believe everyday can become a Electrician with the right learning materials.
My goal with BLOG is to help you learn Electrical.

Labels

LEKULE TV EDITORIALS ARTICLES DC ROBOTICS DIGITAL SEMICONDUCTORS GENERATOR AC EXPERIMENTS MANUFACTURING-ENGINEERING REFERENCE FUNDAMENTAL OF ELECTRICITY ELECTRONICS ELECTRICAL ENGINEER MEASUREMENT TRANSDUCER & SENSOR VIDEO ARDUINO RENEWABLE ENERGY AUTOMOBILE TEARDOWN SYNCHRONOUS GENERATOR DIGITAL ELECTRONICS ELECTRICAL DISTRIBUTION CABLES AUTOMOTIVE MICROCONTROLLER SOLAR PROTECTION DIODE AND CIRCUITS BASIC ELECTRICAL ELECTRONICS MOTOR SWITCHES CIRCUIT BREAKERS CIRCUITS THEORY PANEL BUILDING ELECTRONICS DEVICES MIRACLES SWITCHGEAR ANALOG MOBILE DEVICES WEARABLES CAMERA TECHNOLOGY COMMUNICATION GENERATION BATTERIES FREE CIRCUITS INDUSTRIAL AUTOMATION SPECIAL MACHINES ELECTRICAL SAFETY ENERGY EFFIDIENCY-BUILDING DRONE CONTROL SYSTEM NUCLEAR ENERGY SMATRPHONE FILTER`S POWER BIOGAS BELT CONVEYOR MATERIAL HANDLING RELAY ELECTRICAL INSTRUMENTS ENERGY SOURCE PLC`S TRANSFORMER AC CIRCUITS CIRCUIT SCHEMATIC SYMBOLS DDISCRETE SEMICONDUCTOR CIRCUITS WIND POWER C.B DEVICES DC CIRCUITS DIODES AND RECTIFIERS FUSE SPECIAL TRANSFORMER THERMAL POWER PLANT CELL CHEMISTRY EARTHING SYSTEM ELECTRIC LAMP FUNDAMENTAL OF ELECTRICITY 2 BIPOLAR JUNCTION TRANSISTOR 555 TIMER CIRCUITS AUTOCAD BLUETOOTH C PROGRAMMING HOME AUTOMATION HYDRO POWER LOGIC GATES OPERATIONAL AMPLIFIER`S SOLID-STATE DEVICE THEORRY COMPUTER DEFECE & MILITARY FLUORESCENT LAMP INDUSTRIAL ROBOTICS ANDROID ELECTRICAL DRIVES GROUNDING SYSTEM CALCULUS REFERENCE DC METERING CIRCUITS DC NETWORK ANALYSIS ELECTRICAL SAFETY TIPS ELECTRICIAN SCHOOL ELECTRON TUBES FUNDAMENTAL OF ELECTRICITY 1 INDUCTION MACHINES INSULATIONS USB ALGEBRA REFERENCE HMI[Human Interface Machines] INDUCTION MOTOR KARNAUGH MAPPING USEUL EQUIATIONS AND CONVERSION FACTOR ANALOG INTEGRATED CIRCUITS BASIC CONCEPTS AND TEST EQUIPMENTS DIGITAL COMMUNICATION DIGITAL-ANALOG CONVERSION ELECTRICAL SOFTWARE GAS TURBINE ILLUMINATION OHM`S LAW POWER ELECTRONICS THYRISTOR BOOLEAN ALGEBRA DIGITAL INTEGRATED CIRCUITS FUNDAMENTAL OF ELECTRICITY 3 PHYSICS OF CONDUCTORS AND INSULATORS SPECIAL MOTOR STEAM POWER PLANTS TESTING TRANSMISION LINE C-BISCUIT CAPACITORS COMBINATION LOGIC FUNCTION COMPLEX NUMBERS CONTROL MOTION ELECTRICAL LAWS INVERTER LADDER DIAGRAM MULTIVIBRATORS RC AND L/R TIME CONSTANTS SCADA SERIES AND PARALLEL CIRCUITS USING THE SPICE CIRCUIT SIMULATION PROGRAM AMPLIFIERS AND ACTIVE DEVICES APPS & SOFTWARE BASIC CONCEPTS OF ELECTRICITY CONDUCTOR AND INSULATORS TABLES CONDUITS FITTING AND SUPPORTS ELECTRICAL INSTRUMENTATION SIGNALS ELECTRICAL TOOLS INDUCTORS LiDAR MAGNETISM AND ELECTROMAGNETISM PLYPHASE AC CIRCUITS RECLOSER SAFE LIVING WITH GAS AND LPG SAFETY CLOTHING STEPPER MOTOR SYNCHRONOUS MOTOR AC METRING CIRCUITS BECOME AN ELECTRICIAN BINARY ARITHMETIC BUSHING DIGITAL STORAGE MEMROY ELECTRICIAN JOBS HEAT ENGINES HOME THEATER INPECTIONS LIGHT SABER MOSFET NUMERATION SYSTEM POWER FACTORS REACTANCE AND IMPEDANCE INDUCTIVE RECTIFIER AND CONVERTERS RESONANCE SCIENTIFIC NOTATION AND METRIC PREFIXES SULFURIC ACID TROUBLESHOOTING TROUBLESHOOTING-THEORY & PRACTICE 12C BUS APPLE BATTERIES AND POWER SYSTEMS DC MOTOR DRIVES ELECTROMECHANICAL RELAYS ENERGY EFFICIENCY-LIGHT INDUSTRIAL SAFETY EQUIPMENTS MEGGER MXED-FREQUENCY AC SIGNALS PRINCIPLE OF DIGITAL COMPUTING QUESTIONS REACTANCE AND IMPEDANCE-CAPATIVE SEQUENTIAL CIRCUITS SERRIES-PARALLEL COMBINATION CIRCUITS SHIFT REGISTERS WIRELESS BUILDING SERVICES COMPRESSOR CRANES DIVIDER CIRCUIT AND KIRCHHOFF`S LAW ELECTRICAL DISTRIBUTION EQUIPMENTS 1 ELECTRICAL DISTRIBUTION EQUIPMENTS B ELECTRICAL TOOL KIT ELECTRICIAN JOB DESCRIPTION INDUSTRIAL DRIVES LAPTOP SCIENCE THERMOCOUPLE TRIGONOMENTRY REFERENCE UART oscilloscope BIOMASS CONTACTOR ELECTRIC ILLUMINATION ELECTRICAL SAFETY TRAINING ELECTROMECHANICAL FEATURED FILTER DESIGN HARDWARE JUNCTION FIELD-EFFECT TRANSISTORS NASA NUCLEAR POWER VALVE COLOR CODES ELECTRIC TRACTION FLEXIBLE ELECTRONICS FLUKE GEARMOTORS INTRODUCTION LASSER PID PUMP SEAL ELECTRICIAN CAREER ELECTRICITY SUPPLY AND DISTRIBUTION MUSIC NEUTRAL PERIODIC TABLES OF THE ELEMENTS POLYPHASE AC CIRCUITS PROJECTS REATORS SATELLITE STAR DELTA VIBRATION WATERPROOF