Wall Chasing and Concrete Grooving: Complete How-To Guide for NE India Electricians and Builders

Wall Chasing in NE India: The Case for the Right Machine

Written by the counter team at Multi Trade Combines — 35 years supplying NE workshops.

Wall chasing — cutting channels in masonry for electrical conduits, water pipes, and data cables — is one of the most common and most underestimated tasks in Northeast India's construction sector. From new commercial buildings in Guwahati's fast-growing outskirts to renovation work in Shillong's dense residential areas, chasing is done on almost every electrification job.

The problem: many contractors still use an angle grinder and a chisel, producing rough, over-deep channels, excessive silica dust, and finishes that require bulky filler before plastering. A dedicated wall chasing machine changes this completely. This guide explains how to use one correctly and safely on the wall types common across Assam, Meghalaya, Tripura, and Nagaland.

Blade Selection by Wall Material

Match blade type to wall material — wrong blades glaze and stop cutting

Maximum Chase Depths by Wall Type

Step-by-Step: How to Use a Wall Chasing Machine

1. Mark the chase route on the wall. Use a chalk line or long spirit level to mark both edges of the conduit channel on the wall surface. Conduit channels should run vertically or horizontally — never diagonally. Check behind the wall for reinforcement (use a rebar scanner / cover meter on RCC walls) and for any existing buried services before cutting.
2. Set blade depth and width on the wall chasing machine. Most wall chasers have two adjustable front plates and an adjustable depth stop. Set the disc spacing to match your conduit outer diameter plus 5–8 mm clearance. Set depth to conduit outer diameter plus 10 mm cover. Do not cut deeper than one-third of wall thickness (see depth table below).
3. Connect the dust extraction. A wall chaser shroud connects to a workshop vacuum or dust extractor. This is mandatory, not optional — dry cutting brick and concrete generates crystalline silica dust. Connect the vacuum before starting any cut. In enclosed rooms in NE India's humid climate, dust concentrations build up rapidly. Run the vacuum at maximum suction throughout the cut.
4. Select the correct diamond blade for your wall material. See the blade selection table above. Fitting the wrong blade type — especially a continuous rim blade on AAC blocks — will glaze the blade within one pass and require you to dress or replace it. Segmented blades are the safest default for brick and block work across NE India's varied masonry types.
5. PPE: wear it before you switch on. Minimum: P2 or FFP2 half-mask respirator (not a fabric dust mask), safety glasses with side shields, and hearing protection rated above 20 dB SNR. Wall chasers are loud (typically 100–105 dB at the operator position) and generate fine respirable dust even with vacuum extraction. Anti-vibration gloves reduce hand-arm vibration (HAV) exposure on long sessions.
6. Cut in a single continuous pass. Position the machine at the top of the marked line (or bottom if routing up from a floor socket) and push steadily along the marks at a consistent feed rate. Stopping and restarting mid-cut leaves a step in the groove. On long vertical chases, rest your arms — do not rush the last section.
7. Clear the core (the material between the two cuts). The wall chaser cuts two parallel grooves. The core between them must be removed with a cold chisel or an oscillating multi-tool. For AAC blocks, the core often breaks out cleanly. For brick, use a narrow brick chisel. Work progressively from top to bottom so debris falls clear of the open conduit route.
8. Lay the conduit and plaster. Lay the conduit with saddles at maximum 1 m centres into the channel. Use appropriate plaster mortar to fill around and over the conduit — not just a skim. For waterproofing in bathrooms and wet areas common in NE India's high-rainfall climate, use a water-resistant additive in the filling mortar before final plastering.
9. Clean and inspect blades after the job. Diamond blades used on abrasive materials (AAC, sand-lime brick) wear faster than on dense clay brick. Inspect the segment height after each job — once segments are below 2 mm above the steel core, the blade must be replaced to avoid core strike.

Dust Safety on NE India Construction Sites

Silica dust from concrete and brick cutting is classified as a Group 1 carcinogen. The DGFASLI and Ministry of Labour guidelines require engineering controls (dust extraction) before relying on respiratory protective equipment (RPE). On NE India sites, where ventilation in stairwells, corridor, and basement areas is poor, silica exposure from unchased or poorly extracted chasing operations is a genuine occupational health risk.

Wall chasing machines with properly fitted shrouds and a connected vacuum extractor reduce airborne dust by over 90% compared to open angle grinder cutting. This is the single biggest health benefit of the dedicated machine over improvised methods.

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Frequently Asked Questions