When you undertake building construction a systematic plan is essential. An electrical plan must be decided upon by the home owner/designer to ensure and see that all the outlets, lighting, and power needs work efficiently and effectively.
What is Electrical Chasing?
Electrical chase is a technique used for cutting proper channels in masonry or concrete. Chasing is a continuous recess within the floor, ceiling and walls for the required pipe work and conduit. Generally, the size of channel is 50 to 100 mm in width and 50 to 75 mm in depth.
Electrical chase is a technique, in which the channels (generally 50 to 100 mm min width and 50 to 75mm deep) are chipped or carved in the masonry or concrete elements to place the electrical conduit or other services of house to conceal them in the walls for better aesthetics.
Tools Used in Electrical Chasing Work
- Chase cutter
- Lump hammer
- Large bolster
- Medium bolster
How does Wall Chasing Work? /How is Wall Chasing Done?
During the floor or wall treat, hand-held cutting tools, which have a double diamond blade are used for cutting brickwork. In the process, two slots are cut to a specific depth and width. The Centre part of concrete masonry is removed by using a small breaker or a hammer drill like these on ToolsFirst. This technique is quick and dust-free.
How to Cut Chase?
Cutting chase is a simple job and most professional electricians have their own chasing tools for the purpose. Basically an angle grinder with two parallel cutting blades with a depth setting is used. The depth gauge simply sets and runs the grinder up/ down or across the wall making two parallel cuts. The waste between the cuts is knocked out with the use of a cold chisel.
According to DMRC (Delhi Metro Rail Corporation Limited) Electrical Standards & Design Wing, 2015 the sufficient width of chases shall be minimum 10 mm (distance between nearby conduit) to provide a required number of a conduit. The Depth of full thickness of plaster should be minimum 6mm over conduits.
Guidelines for Cutting Electrical Chases in Brick Wall
01. Cutting of Electrical Chases in One Brick Thick and Above Load Bearing Wall:
(a) As far as possible, the services should be planned with the help of vertical chases. Horizontal chases should be avoided, as they reduce the strength of the wall.
(b) The depth of vertical chases and horizontal chases shall not exceed one-third and one-sixth of the thickness of the masonry respectively.
(c) When horizontal chases are unavoidable it should be located in the upper or lower one-third height of storey and not more than three chases should be permitted in any stretch of a wall.
(d) No continuous horizontal chases shall exceed 1 meter in length.
(e) Vertical section should not be closer to 2 meters in any stretch of a wall.
(f) Electrical Chase shall be kept away from bearings of beams and lintels.
(g) If unavoidable, stresses in the affected area should be checked and kept within permissible limits.
(h) No vertical chases for fixing electric conduits or G.I pipes or a recess for fixing electrical metal boxes should be cut within 1.5 feet from the edge of the wall.
2. Cutting of Electrical chases in half brick thick load bearing walls:
Half brick thick walls are normally not used as load bearing wall, but if at all used, no chases shall be permitted in load bearing walls having a thickness of half-brick. Ideally, no recessed conduits and concealed pipes shall be provided in load bearing walls having a thickness of half-brick only.
03. Cutting of Chases in Half Brick Non-Load Bearing Wall:
Services should be planned with the help of vertical chases. Horizontal chase should be provided only when vertical chase is not possible, however one should try to avoid it.
How to Fill Electrical Chase?
Once the cable is kept or installed in place, use a paint brush to wet the sides and back of the chase by using clean water, and then apply a coat of neat PVA adhesive to the sides/back of the chase and conduit/ pipe. This will aid the adhesion of the filler.
As a filler, the materials to be used are:
- A strong sand/ cement mix (3:1:1 – 3 part of soft sand: 1 part of sharp sand: 1 part of cement).
- One coat of plaster or patching plaster,
- A standard decorator’s filler.
If applied to a deep chase, both the plaster and filler may sag and hence they need to be built up in layers.
The chases must be filled from the back and around the conduit/ pipe from the front. A small trowel will help push the filler into the back corners and behind the conduit/ pipe. Use the trowel across the sides of the wall surface to cut off the filler to the line of the wall. If channeling is used, there is no need to try to fill the chase behind it.
If the wall is to be tied, there is no need to give a fancy finish to the wall. But if the wall is to be painted or papered, cut back the surface of the filler by about 3 mm before it fully hardens.
Chases can also be filled with a plaster which is called patching plaster or one coat plaster. This can generally be applied in coats up to 50 mm thick. If there is a deep chase, build the fill up in layers. If using one coat plaster, make sure that you wet the chase really well before applying it. The plaster will dry out quickly and crack badly if its moisture content is not maintained, you may add fibers like Recon fibers with mortar for filling the chases.
If you follow the guidelines which are mentioned above, you will not face any major problem in the future due to chases in wall.