Conduit is a tubular (round) pipe which is made up of MS or PVC (sometimes GI pipe may also be used). Conduit provides a safe path for wires (from mechanical protection) which are laid inside it. Conduit is laid between two boxes & these boxes may be switch box, fan box, junction box etc. Some accessories are also used when conduiting is done such as bends, sockets, junction boxes (JB), switch boxes etc.
Mostly two types of conduits are used for wiring purpose – 1.PVC (Polyvinyl chloride) conduit &2.MS (Mild Steel) conduit.
Accessories for conduit–
Following accessories are used with PVC/MS conduits –
- Bend (or long bend) – As a conduit is a hard material so it needs some material which can be used to change the direction of conduit. SO, a bend is used to change the directing of conduit such as from straight to up/down or left/right etc. Generally a bend provides 900 angle to the conduit.
(Note – when a small change in direction is required for a conduit, then off set is used. Off set is method by which conduit can be bentmanually or with the help of bending machine.)
- Socket – It is used to connect two conduits. The diameter of socket is slightly higher than the conduits. Two conduits are inserted from both sides of a socket & an adhesive solvent is used to fix the conduit with socket in case of PVC while socket of MS conduit has threads inside It therefore conduit must have threads on outside of the conduit. Threads on outside of the conduit can be provided with thread making machine manually or through machine.
- Junction box–It is used to split the wires & also helps to pull the wire. Junction boxes are of various types – 1way,2way, 3way,4way, deep JB, surface JB, round JB, rectangle JB etc.
- Fan box – is used to hang the fan & connected with conduit so that required wires could reach up to fan for electrical connection. Generally it is used during slab casting for concealed conduiting. Fan hooks are also used which can be fixed on the ceiling.
- Saddles – Saddles are used to fix the conduit on surface.
- Inspections bend – It is used with MS conduit only. It serves to purpose – a) to change the direction of conduit and b) as a junction box.
- Check-nuts – It is used with MS conduit only as it fixes the MS conduit with junction boxes/switch boxes.
TYPES OF CONDUITING –
Conduiting means laying of conduits.Two types of conduiting is done for electrical wiring – 1) Surface conduiting& 2) Concealed conduiting.
- Surface Conduiting – In surface conduiting, conduits are laid on the wall surface. First of all, a route is marked with the help of thread which is soaked in blue/brown/read color powder. Then holes are made at a fixed distance & then base is fixed through the screw in the line drawn with color. powder. Then conduit is placed on the base & conduit is fixed with saddle. In this process wall cutting is not required. Conduit is visible on walls in surface conduiting.
- Concealed conduiting – In this type of conduiting, a groove is made on the wall with the help of either hammer- chisel (manually) or a cutting machine. The size of groove depends on the diameter of conduit. Grooves are made in the brick wall (before plastering work on wall). Finally conduit is placed in the grove. Conduit is fixed in the groove with binding wire & then final plaster on wall is done. In this case, after final finish of the wall, conduit is not visible on wall. Concealed conduiting is done in wall & slab.
Concealed wall conduiting is done for making electrical points on walls while Slab conduiting is done for making point on ceiling.
(Note– Deep Junction boxes are used for slab conduiting while surface junction boxes are used for wall conduiting.)
RANGE OF CONDUITS –
Conduits are available in various sizes such as -19mm dia, 25mm dia, 32mm dia, 40mm dia etc. The size of conduit depends on the number of wires to be laid through it.
Generally 19mm & 25mm dia conduits are used in lighting & power wiring while 32mm & 40 mm dia is used for submains wiring.
TYPES OF CONDUITS –
There are two types of conduits are used – Solid conduit & flexible conduit. Solid conduits are used in slab conduiting& surface conduiting while flexible conduits are used for temporary protection of wires especially during surface wiring such as above false ceiling or areas where solid conduit is not possible to lay.