Besides, the conduit line shall not come in contact with a water pipe or a gas pipe. Throughout the entire length of a conduit line wherever there is a turning point, a bend with a radius of curvature not less than 75 mm should be used there. For this reason use of elbow is prohibited at many points. Where elbow is a necessity, it should be provided with an inspection hole. This helps to draw wires easily at a corner point. In a good installation sometimes for drawing wires use of gas pipes is insisted in place of conduit pipes.
Such an arrangement is adopted where it is necessary to keep the wires well-protected and where wiring line is drawn along the outer wall of a house. But in such cases it should be borne in mind that the gas pipes may rust as its inner surface is not stove enamelled and smooth as that of a rigid conduit.
For this reason it is better to draw lead covered cables through the pipes, and cost of wiring should not be the main consideration in such cases. In this connection another point is also to be noted. Wherever there is a turning point, inspection bend, inspection tee, etc. Otherwise it will not be easy to draw lead covered cables through the pipes. Farther, a brass adapter is to be fitted at each point where a conduit is joined with a gas pipe. This is because the nature of threads in a conduit is not the same as that of a gas pipe.
The inner surface of the adapter is gas-threaded which fits with the gas pipe and its outer surface is electrical-threaded to match with the conduit. The size outer diameter of the gas pipe fits with the inner diameter of the adapter at one end, while the inner diameter of the conduit fits with outer diameter of the adapter at the other end.
This is an essential point to be noted. In case a conduit is drawn through floor, roof or wall, its continuity is tested immediately after installation and before completion of floor, roof or wall to see whether its resistance is as low as desired.
If the installation work is properly done, almost in all cases the resistance is found to be 0. Conduit is installed by means of spacing saddles fixed on wooden plugs which are grouted into the wall at an intervals of about one metre or less.
At the time of installation it should be observed that there is some clearance between conduit and the wall. It is for this clearance that the spacing saddle is at first placed on the wooden plugs and then the conduit is fixed over it fig. Spacing saddle has many utilities. First, the hole through which the base of the saddle remains fixed on the wall with the help of screws is not round but oval in shape enabling us to move the saddle a bit this way or that way when necessary.
This facilitates right and straight installation of conduit line. Second, the two holes through which the screws are driven to fix the saddle with the base are split fig. This helps to take out the saddle from the base easily. Also little adjustment here and there is possible without any difficulty. Moreover the screws need not be fully unscrewed; only a little loosening is enough to remove or to re-set the saddle.
Often specially in cheap work saddles shown in fig. But this keeps the conduits in contact with the wall. Hence, use of such type of saddles should be avoided as far as possible. The type of saddle used to install two or more conduits side by side together is known as Multiple Saddle. Such a Saddle in shown in fig. At the time of fixing conduit, switch box, joint box, ceiling rose and other accessories should be fixed simultaneously in order to complete the conduit installation.
Wooden block should not be used in conduit wiring. Where a conduit is to pass through a wall, it should at first be well-fixed with the wall so that switch, bracket and other fittings may not become loosened afterwards.
If there are too many bends and turns in an ordinary small room, it is the usual practice to draw a piece of long and narrow steel wire through the conduit along with the progress of fixing bends switch-box etc. This is not P. Later on as many P. All the cables are now easily drawn up through the conduit. The piece of narrow steel wire is called Pulling-in-Wire or Fish-Wire. Since the drawing of cables through a straight run of conduit line is comparatively easy, often G.
In case there is possibility of drawing a few more cables in future, a conduit pipe of larger diameter shall be used and along with single-core P. The leads of the additional cables will be tied up with the pulling-in-wire in future and the cables will be drawn through the conduit.
The insulation of cables is cut off to some length and all wires are twisted together at one end. This end is then bent into a ring. The remaining bare wires are twisted together and tightly wound round the loose side of the wires so that the ring does not yield at the time of pulling.
Later, all these should be so nicely taped that the bundled end becomes tapering. As the slippery condition is convenient for pulling in, the bundled end is well smeared with French chalk or paraffin wax. At last the end of the pulling-in-wire is tightly twisted with the ring before pulling the cables. The precaution to be observed at the time of drawing the cables is that inside the conduit the cables do not intertwine themselves.
This will make not only drawing of cables difficult on account of less space inside the conduit, but also it will become an impossible job to draw out one cable from the conduit when required. While drawing cables through a conduit, it becomes more troublesome to draw unbraided P.
For this reason it is necessary to use more conduit boxes. There are several different types of wire insulation which will have a determination about the application the wire may be used for. The temperature rating is just one factor to consider when selecting a wire type.
The amount of wire fill inside a conduit must be configured properly to prevent overheating of the wire, which is why conduit fill tables are very important.
Get a Quick Reply! Ask the Electrician. Jane from Panama city , Florida. Estimated Time: Depends on personal level of working capabilities and electrical experience, electrical certification or contractors license, ability to work with tools, install electrical circuit wiring, and the available access to the project area.
Electrical Safety: Identify the electric panel circuits found in the project area, turn them OFF and Tag them with a Note before working with the electrical wiring. Electrical Wiring Parts and Materials: Electrical parts and materials for all electrical projects should be approved for the specific project and compliant with local and national electrical codes.
Electrical Codes and Inspections: Installing additional electrical circuits or wiring should be done according to local and national electrical codes with a permit and be inspected. NEC Table C. Flexible metallic electrical conduit is used principally in commercial and industrial construction world wide. In residential applications you may find FMC used to connect an electric oven or electric cooktop. LFMC is described in the U. Flexible metal conduit is sold in rolls and cut to the necessary length, joined with appropriate fittings.
Intermediate Metallic Conduit or IMC is lighter weight, metallic conduit and is rated as stronger than other rigid conduit. IMC, provided in both threaded IMC and non-threaded IMC forms, is a rigid metallic conduit tubing, typically hot-dipped galvanized steel or stainless steel. The interior of galvanized steel IMC is usually coated with an anti-corrosion layer.
Threaded IMC is joined by threaded couplings, C condulets, sweeps and bends. The tubing is cut with a pipe cutter or tubing cutter, and then threads cut using a thread cutting tool. When cutting IMC, take care to remove burrs on the tubing interior that would otherwise damage electrical wires being pulled through the conduit. IMC is typically used in hazardous locations, and in its stainless steel formulation, IMC is widely used in the food and beverage industry, in chemical plants, in cosmetic and pharmaceutcial industries, in refineries, in pulp and paper mills, in marine and coastal sites, in other corrosive environments.
An advantage of IMC is its larger interior diameter compared with RMC of the same nominal sizes, making it easire to pull wires. There the flexible whip avoids problems with vibration-loosened connections in the conduit. Watch out : Flexible conduit and whips are "flexible" but not to degrees that exceed the laws of physics and the properties of the materials. If you force flexible conduit or a pre-wired conduit whip to bend too acutely over too short a radius such as at its connection to a rigid surface the conduit will eventually break, as Tim Hemm's photograph left illustrates.
Rigid metal conduit is a heavier gauge steel electrical conduit using threaded couplings and fittings and is the thickest, or stiffest of the conduit materials used for electrical wiring. A typical RMC and often the only RMC residential application is to enclose the electrical service entry wiring from the electrical company's overhead wires at the mast-head down to the electrical panel mounted on the building wall. This sort of damage can happen when a tree falls on the electrical wires between pole and masthead.
Calbrite This website provides information about a variety of electrical hazards in buildings, with articles focused on the inspection, detection, and reporting of electrical hazards and on proper electrical repair methods for unsafe electrical conditions. Carl Youngblut, Because I have not found a rigid metal or plastic conduit that was sold pre-wired, I think you're going to be looking at a pre-wired flexible conduit either metallic or nonmetallic.
This flexibility also allows you to install wiring without having to cut it to an exact length. Looking to do the "install" of conduit and wiring along wall before calling electricial to hook to cuiruit box and wall socket.
On by inspectapedia. The boxes, connectors, and conduits form a wire enclosure system called a raceway. A raceway is an enclosed conduit that forms a physical pathway for the electrical wiring to follow. In this way, the metal raceway acts in place of the grounding wire that is found in non-metallic cable.
This is also the main reason why only metal boxes may be used with metal conduit. This type of grounding system was more common in older construction than it is today, and many electricians today include an insulated ground wire in a metal conduit as preferred means of grounding the circuit.
For a metal raceway to serve as a grounding system, all parts of the raceway must be electrically connected, with no interruptions. If a remodeler unwittingly installs a plastic box in the raceway, or if any connection comes loose, the ground path will be broken, leaving the circuit ungrounded. Actively scan device characteristics for identification. Use precise geolocation data. Select personalised content.
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