Electrical Conduit and Junction Boxes PDF

WHAT IS JUNCTION BOX? A junction box – also known as an Purposes: ‘electrical box’, ‘jbox’, ‘or ‘terminal box’ – is a protective box where wires are It protects people from coming into contact interconnected. Junction boxes are often with live wires built into the...

WHAT IS JUNCTION BOX? A junction box – also known as an Purposes: ‘electrical box’, ‘jbox’, ‘or ‘terminal box’ – is a protective box where wires are It protects people from coming into contact interconnected. Junction boxes are often with live wires built into the plaster of a wall, in the It protects your wires from dust and ceiling, or within concrete. They are dampness standard within most homes, buildings, It prevents small critters (rats) from and factories. chewing on your wires It organizes the electrical floor plan into Junction boxes are found both indoors units and outdoors. Waterproof junction It prevents fires within the junction box boxes are commonly used outdoors. from spreading (when properly covered) Junction boxes are typically made of metal or plastic. JUNCTION BOX  WHAT IS JUNCTION BOX? There 4 main electrical junction box types: Metal junction box PVC junction box (plastic) ABS junction box (plastic) Fiberglass junction box (fiber-reinforced plastic) JUNCTION BOX  WHAT IS UTILITY BOX? Utility boxes are above- ground structures that house electrical transformers, electrical switches, cable TV, communication or telephone connections and wiring, and other electrical connections required to distribute a utility service from a main line to individual buildings. UTILITY BOX  WHAT IS ELECTRICAL CONDUIT? - Physical pathways created in order to run wiring in a building. - They serve to guide and protect wiring. ELECTRICAL CONDUIT TYPES AND ACRONYMS RMC: Rigid Metal Conduit RMC stands for “rigid metal conduit”. It’s one of the most heavy-duty types of electrical conduit and uses galvanized steel for its construction. As an outdoor-friendly conduit, it provides outstanding protection from environmental and physical damage. It’s also capable of providing structural support for boxes, cables, and other electrical equipment. ELECTRICAL CONDUIT  ELECTRICAL CONDUIT TYPES AND ACRONYMS IMC: Intermediate Metal Conduit Intermediate metal conduit (IMC) is a toned-down version of RMC that’s thinner and lighter. Even though it’s not as thick, it’s typically approved for all of the same applications as RMC. Given the choice between the two, our electricians prefer IMC simply because its lighter weight makes it much easier to deal with. EMT: Electrical Metallic Tubing EMT stands for “electrical metallic tubing” and is a type of rigid metal conduit. You normally see it made from galvanized steel and it also shows up as aluminum in some cases. As a thinner metal tube, it’s easy to bend and kink. When you’re installing EMT, you use a conduit bender to make your bends without kinking and a compact or 12V reciprocating saw with a high TPI blade is all you need to cut it. ELECTRICAL CONDUIT  ELECTRICAL CONDUIT TYPES AND ACRONYMS FMC: Flexible Metal Conduit Way back before most of us were born (the early 1900s), Harry Greenfield invented a flexible metal conduit (FMC). Using steel or aluminum for construction, it has a distinct spiral look to it that allows it to flex over short distances much easier than EMT. It has a big advantage when you need to add conduit in tight spaces or around existing equipment. LFMC: Liquid-Tight Flexible Metal Conduit LFMC, or liquid-tight flexible metal conduit, is similar to FMC but covered in a waterproofing coating. It’s useful for outdoor applications and wet interior areas and requires fittings that are also watertight. Typical Fastening Style: Threaded Common Sizes: 1/2″ – 4″ Common Applications: Outdoor and indoor wet areas ELECTRICAL CONDUIT  ELECTRICAL CONDUIT TYPES AND ACRONYMS ENT: Electrical Non-Metallic Tubing It’s a flexible PVC tubing that looks a lot like a pool hose. You can encase it in concrete, run it behind walls and under floors, and use it as a replacement for EMT. The major manufacturer for ENT uses 2- hour fire resistant rated materials. ENT is not UV-resistant, though, so using it where it will be exposed to UV rays is out. ELECTRICAL CONDUIT  ELECTRICAL CONDUIT TYPES AND ACRONYMS Rigid PVC Conduit Rigid PVC is a very familiar material to many folks thanks to its similarities to the PVC we use in plumbing and irrigation. Unlike EMT, you can’t use a conduit bender to manipulate it. PVC needs to be heated before in order to bend it. Typically that happens using a heater box but you can use a heat gun as an alternative in the field. As a conduit, rigid PVC shares the same characteristics as water pipe: you glue it together and it’s water-tight when you install it correctly. That makes it useful for direct burial underground and it’s allowable in corrosive environments. You can also encase it in concrete, conceal it in walls, or leave it exposed. ELECTRICAL CONDUIT ELECTRICAL SYMBOLS ELECTRICAL SYMBOLS ELECTRICAL SYMBOLS LIGHTING LAYOUT PLAN POWER LAYOUT PLAN SAMPLE FLOOR PLANS SAMPLE ELECTRICAL LIGHTING LAYOUT SAMPLE ELECTRICAL POWER LAYOUT ACTUAL SAMPLES ACTUAL SAMPLES ACTUAL SAMPLES ACTUAL SAMPLES ACTUAL SAMPLES ACTUAL SAMPLES ELECTRICAL SYMBOLS RISER DIAGRAM A SINGLE LINE DIAGRAM PRESENTATION OF THE ENTIRE ELECTRICAL CIRCUIT FROM THE SERVICE ENTRANCE UP TO THE SMALLEST CIRCUIT BRANCH. IT SHOWS THE FOLLOWING INFORMATION: 1. CHARACTER AND TYPE OF SERVICE – SINGLE PHASE 2 WIRES / 3 WIRES 2. SIZE OF SERVICE ENTRANCE CONDUIT AND SIZE OF WIRE USED 3. TYPE AND SIZE OF WIRE FOR EACH BRANCH OF CIRCUIT - SIZE NO. 12 (COMMONLY USED), TYPE THHN OR THWN WIRES 4. SIZE OF PROTECTIVE DEVICE FOR THE MAIN AND BRANCH CIRCUIT – CIRCUIT BREAKER, WILL INTERRUPT THE FLOW OF THE ELECTRICITY, DURING OVERLOAD OR SHORT CIRCUIT RISER DIAGRAM RISER DIAGRAM What Is THHN Wire? Thermoplastic high What is THWN Cable? THWN is a heat nylon (THHN) wire is a single code for thermoplastic heat and conductor general-purpose building water resistant which is suitable for and hook-up wire. The first letter T use in both dry and wet locations shows the insulation is a thermoplastic with a maximum temperature rating material made from polyvinyl chloride of 75ºC (167ºF). (PVC). THHN/THWN WIRE GAUGES SIZE AND WIRE AMPACITY  COMPUTATION OF LOADS COMPUTATION OF LOADS IS ONE OF THE MOST IMPORTANT PART OF AN ELECTRICAL PLAN, WHERE IN WE CAN DETERMINE THE NUMBER OF LIGHTING OUTLET, CONVENIENCE OUTLET, SPECIAL PURPOSE OUTLET AND EACH CURRENT CAPACITY. WE ALWAYS FOLLOW AND OBSERVE THE COMPUTATION OF LOADS FOR SAFETY REASON, TO AVOID SHORT CIRCUIT AND OVERLOADING OF ELECTRICAL APPLIANCES. ALWAYS UPGRADE THE ELECTRICAL SYSTEM OF A HOUSE TO PREVENT FAULTY ELECTRICAL WIRING AND UNAVOIDABLE CIRCUMSTANCES. OF TIME. COMPUTATION OF LOADS  COMPUTATION OF LOADS COMPUTATION OF LOADS