What is the difference between SDS Plus and SDS Max?

SDS (Slotted Drive System) is a chuck system that allows hammer drill bits to slide in and out within the chuck, enabling the hammering action without transmitting rotational shock to the chuck mechanism. SDS Plus is the smaller format — bits have a 10mm shank diameter with two open grooves and two closed grooves for retention. SDS Plus is the standard for domestic and commercial electrical drilling: cables passes through masonry and brick, back box recesses, and light core drilling up to approximately 100mm diameter. SDS Max is the larger, heavier format — bits have an 18mm shank diameter with three open grooves and two closed grooves. SDS Max delivers significantly higher impact energy and is used for heavy-duty core drilling through thick reinforced concrete (150mm+), large-diameter anchoring, and breaking work with a demolition chisel attachment. An electrician working on domestic and light commercial projects will find SDS Plus covers the vast majority of jobs. SDS Max is only needed for specialist core drilling into reinforced concrete structures.

Is 18V enough for SDS drilling through brick and block?

Yes, for the vast majority of domestic and commercial electrical work. A modern 18V brushless SDS Plus drill (such as the Makita DHR171, DeWalt DCH273, or Milwaukee M18FHX) has sufficient impact energy to drill through dense brick, lightweight block, medium-density concrete block, and un-reinforced concrete for cable passes, back box chases, and containment penetrations. The key variable is battery capacity — a 5Ah or 6Ah battery provides sustained power for extended drilling runs without voltage sag. Where drilling becomes slow on dense concrete or involves core bits above 82mm diameter through thick sections, a 54V (XR FLEXVOLT, Multi-Volt) tool will maintain drilling speed better and reduce battery drain per hole. For specialist work involving reinforced concrete slabs, structural walls, or large-diameter through-wall cores, hire a professional core drilling rig rather than overloading a standard cordless SDS Plus.

What hole saw do I need for surface back boxes?

For flush-mounted back boxes in plasterboard, a 68mm hole saw cuts the aperture for a standard single or double gang surface back box in plasterboard — but practice varies by manufacturer. Check the back box dimensions first: most 1-gang flush boxes require a 60–68mm cut; 2-gang flush boxes require a different aperture or two overlapping cuts. For plasterboard and MDF, a standard bi-metal hole saw works well. For brick or dense plaster, use a carbide-tipped or diamond hole saw. The most versatile general-purpose hole saw sets for electricians cover 16mm to 82mm (for cable conduit entries, armoured cable glands, and back box apertures). Arbor sets with quick-release bits speed up changing between sizes on site.

What drill do I need for SWA cable entry through masonry walls?

For steel wire armoured (SWA) cable entry through a masonry external wall, the required hole diameter depends on the cable diameter plus the fitting (weatherproof gland or conduit entry bushing). Typical 2.5mm² 3-core SWA requires a 25–32mm hole. A 6mm² or 10mm² 3-core SWA cable entry requires 40–50mm minimum. For holes up to 50mm, an SDS Plus drill with a core drill bit and depth stop is appropriate. For holes above 50mm through solid brick or block, a dedicated core drill (diamond or TCT bit on a rotary-only core drilling machine, or a high-powered SDS Plus rotary core bit) produces a cleaner, straight hole with less effort. Always use a cable detector before drilling through external walls to check for hidden services.

How do I drill cleanly through ceramic tiles for electrical work?

Ceramic and porcelain tiles require a diamond or carbide spear-point tile drill bit — never use a standard twist drill or masonry bit, which will crack the tile glaze. For small holes (up to 12mm) for switch or socket fixings, a diamond-tipped pilot hole bit followed by a carbide spear-point bit at low speed (no hammer) with water cooling produces a clean hole. For larger holes for conduit or flush boxes in tiled areas, use a diamond core drill bit with a guide template to prevent the bit wandering on the smooth tile surface. Speed — use slow rotary speed with no hammer action on the drill. Pressure — moderate, constant pressure; excessive force shatters tiles. Water cooling — essential for diamond bits to prevent overheating and bit failure.

Do I need a separate combi drill and SDS drill, or can one do both?

In theory, some SDS Plus drills have a chuck adapter that accepts standard round-shank bits, and some combi drills have a hammer function. In practice, the hybrid approach has limitations. SDS drills with chuck adapters are heavier and bulkier than a dedicated combi drill — not ideal for driving screws or drilling timber all day. Combi drills with hammer function have much lower impact energy than a dedicated SDS drill — adequate for occasional light masonry work but not for sustained drilling through brick or concrete. For professional electrical work, two tools is the correct answer: a compact cordless combi drill (18V, around 1.5kg) for general screwdriving, timber, and plasterboard, plus a dedicated SDS Plus hammer drill for masonry and concrete. The combined cost of two quality 18V tools on the same battery platform is justified by the difference in comfort and productivity over a full working day.

What is a brushless motor and why does it matter?

A brushless DC motor eliminates the carbon brushes used in traditional commutated motors. Brushes create friction and wear — they need periodic replacement and generate heat. Brushless motors use permanent magnets and electronic commutation, eliminating brush friction and making the motor significantly more efficient (less heat, less energy wasted). For cordless power tools, brushless motors deliver more power per amp-hour of battery, run cooler in sustained use, and last longer. The practical benefits for electricians are longer battery runtime per charge, sustained torque and speed in heavy drilling without overheating, and longer tool service life before motor wear requires attention. Modern 18V brushless SDS Plus drills deliver performance that matches older 24V brushed tools. All the recommended drills in this guide (Makita DHR171, DeWalt DCH273, Milwaukee M18FHX) use brushless motors.

TOOLS & EQUIPMENT GUIDE

Drill Guide for Electricians: SDS, Cordless, and Hole Saws for UK Electrical Work 2026

Everything UK electricians need to know about drills — SDS Plus vs SDS Max, 18V vs 54V cordless platforms, hole saw sets for back boxes and cable entries, core drilling for containment, and the best drills for electrical installation in 2026.

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13 min readUpdated 2026-06-10Andrew Moore, Founder of Elec-Mate

Written and reviewed by Andrew Moore, founder of Elec-Mate, against BS 7671:2018+A4:2026, IET Guidance Note 3 and the IET On-Site Guide.

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Key Takeaways

1Electricians need three drilling tool types: a compact cordless combi drill for general work, an SDS Plus hammer drill for masonry and concrete, and a hole saw kit for back boxes and cable entry points.
2SDS Plus is the correct chuck system for domestic and light commercial electrical drilling. SDS Max is for heavy-duty core drilling and demolition. Standard keyless chuck combi drills suit timber, plasterboard, and light masonry.
318V cordless platforms provide all the power needed for typical domestic electrical work. 54V (XR FLEXVOLT or equivalent) platforms suit heavy-duty SDS drilling, continuous core drilling, and high-current SDS Max work.
4For back box installation, a 25mm (1-gang) or 35mm (2-gang) holesaw in plasterboard, combined with a chisel for the brick plaster key, is the standard approach. Bi-metal or carbide hole saw sets are the most versatile.
5The Makita DHR171, DeWalt DCH273, and Milwaukee M18FHX are the leading cordless SDS Plus drills for UK electricians in 2026. All three use 18V platforms with extensive compatible tool ecosystems.

01 · Tools & Equipment Guide

Choosing the Right Drill for Electrical Installation Work

Drilling is one of the highest-frequency physical tasks in electrical installation. Back boxes, cable routes through joists, masonry, concrete, containment penetrations, and SWA cable entries through external walls — each requires a different combination of bit type, chuck system, and tool power.

Using the wrong drill or bit for the material slows the job, damages materials (cracked tiles, torn plasterboard), and shortens tool life. Understanding the strengths and limits of each drill type allows you to build a kit that covers all common electrical installation scenarios efficiently.

This guide covers the three chuck systems used in electrical work (standard keyless, SDS Plus, SDS Max), the difference between 18V and 54V cordless platforms, hole saws for back boxes and cable entries, core drilling for containment penetrations, and the best drills available for UK electricians in 2026.

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02 · Tools & Equipment Guide

SDS Plus vs SDS Max vs Standard Hammer Drill

The chuck system determines the types of bits the drill accepts and the level of impact energy it can deliver:

Standard Keyless Chuck (Combi Drill)

Accepts standard round-shank and hex-shank bits: wood, metal, and light masonry twist drills, screwdriver bits, and small hole saws. The keyless chuck grips the bit concentrically. Best for timber frame work, plasterboard, light masonry, and screwdriving. The hammer function on a combi drill provides limited percussive action — adequate for occasional light brick drilling but not sustained masonry work. Weight: typically 1.3–1.8kg. The everyday tool for most electrical first-fix and second-fix work.

SDS Plus

10mm shank with two open slots and two closed retention grooves. The bit slides axially in the chuck, allowing the hammer mechanism to drive the bit directly without transmitting shock to the chuck bearing — enabling sustained high-frequency hammering without premature bearing wear. SDS Plus drills deliver 1.5–3.5J of impact energy per blow at up to 4,500 blows per minute. Suitable for: dense brick and block, light concrete, back box chases, cable route drilling through masonry, and core bits up to 100mm through un-reinforced masonry. The correct choice for most electrical installation masonry drilling.

SDS Max

18mm shank with three open slots and two closed retention grooves. Delivers 5–20J of impact energy per blow. Used for demolition chiselling, large-diameter core drilling through reinforced concrete, and anchor boring in structural concrete. Not a tool most domestic electricians carry — typically hired for specific heavy-duty tasks. Core drilling rigs (rotary-only, no hammer, with water cooling) are the preferred approach for large- diameter structural core drilling in most electrical installation scenarios.

The practical kit for a domestic or commercial electrician is a standard combi drill plus an SDS Plus hammer drill, both on the same 18V battery platform. This covers all common drilling tasks without the weight and cost of SDS Max equipment.

03 · Tools & Equipment Guide

Cordless Voltage Ratings: 18V vs 54V Brushless

Cordless power tool platforms have converged on 18V as the standard for most professional hand-held tools, with 54V (XR FLEXVOLT by DeWalt, Multi-Volt by Hikoki/Hitachi, and 18V×2 parallel systems by Makita and others) available for high-power applications:

18V Brushless

Sufficient for all domestic electrical work, the majority of commercial first-fix and second-fix, and light to medium masonry drilling. Modern 18V brushless SDS Plus drills (1.5–3.0J impact energy) handle standard brick, dense block, and un-reinforced concrete without difficulty.

+Lighter tool weight
+Larger ecosystem of compatible tools
+Lower battery and charger cost
–May slow on sustained dense concrete drilling

54V / High-Power

Maintains drilling speed and torque under sustained heavy load. Advantages emerge in: continuous large-diameter core drilling (68mm+ through dense masonry), sustained SDS drilling in reinforced concrete, and high-demand environments (commercial, industrial sites with long daily drill runs).

+Higher sustained power output
+Less battery sag on heavy sustained loads
–Heavier tool and battery
–Higher initial cost
–Smaller compatible tool range

For most electricians, an 18V brushless SDS Plus drill with a 5Ah battery is the optimal balance. The 54V platform makes sense if you regularly do heavy structural drilling or large-diameter core work as a core part of your business.

04 · Tools & Equipment Guide

Hole Saw Sets for Back Boxes and Cable Entries

Hole saw sets are indispensable for electrical installation. The key applications and recommended sizes are:

Back box apertures in plasterboard: 68mm for single gang, variable for double gang (check back box manufacturer dimensions). Bi-metal hole saws cut plasterboard, MDF, and timber cleanly. Use a guide template for accurate positioning. A sharp pilot drill centres the hole saw correctly.
Conduit entries (20mm and 25mm): Standard electrical conduit diameters. 25mm hole saw cuts through timber, plasterboard, and light sheet metal for conduit pass-throughs. A step drill (Unibit) also cuts clean conduit entry holes in thin sheet materials.
Cable gland entries through metal enclosures: 20mm, 25mm, 32mm, and 40mm for standard metric cable glands. Bi-metal or carbide hole saws cut steel enclosure knockouts cleanly. Always de-burr the cut edge before fitting the gland.
SWA external wall entries: 32mm to 68mm depending on cable size. Diamond or carbide TCT core drill bits for masonry wall penetrations at these diameters — standard bi-metal hole saws are not suitable for sustained masonry drilling.

A comprehensive electrician's hole saw set covering 16mm–83mm in bi-metal with quick-change arbors costs approximately £40–£80 and covers the majority of installation scenarios. Keep masonry core bits separate from wood/metal bi-metal sets — contaminating bi-metal bits with masonry dust significantly reduces their life.

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05 · Tools & Equipment Guide

Core Drilling for Cable Containment

Core drilling for cable containment — running conduit, trunking, or armoured cable through walls, floors, and ceilings — requires larger diameter holes (50–150mm) than standard hole saws can practically produce through masonry. The approach depends on the material:

Brick and block walls (un-reinforced): Tungsten carbide tipped (TCT) core bits in an SDS Plus drill handle brick and block from 50mm to 100mm. Slower than diamond but no water cooling required. Suitable for the majority of domestic external wall cable entries and internal wall containment penetrations.
Concrete and reinforced floors: Diamond core bits with water cooling on a rotary-only core drilling machine (no hammer). The diamond segments cut smoothly through aggregate and rebar without the percussion that would shatter the concrete around the hole. For one-off penetrations, hire a core drilling rig with a vacuum anchor and water supply rather than attempting to hand-hold a large core bit.
Timber floors and joists: Standard bi-metal hole saws on a combi drill. Note structural rules — notches and holes in joists must comply with Approved Document A and the Building Regulations. Consult the engineer or building control for structural members. Fire stopping of any penetration through a compartment floor or fire-resistant wall is required under Building Regulations.

Always detect before drilling

Use a cable detector before any drilling through walls, floors, or ceilings — including internal partitions. Hidden cables and pipes behind plasterboard are a common cause of electrical accidents during building alteration work.

06 · Tools & Equipment Guide

Best Drills for Electricians 2026

These are the leading recommendations across the three tool categories for UK electricians in 2026:

Makita DHR171 (18V SDS Plus)

Best SDS Plus for Electricians — ~£160 (body only)

18V LXT brushless SDS Plus. 1.5J impact energy. XPT (Extreme Protection Technology) sealing for dust and rain resistance. Anti-vibration AVT mechanism reduces operator fatigue during sustained drilling. Compact and lightweight (1.9kg without battery) — important for overhead work and confined spaces typical in electrical installation. Makita LXT is the largest 18V platform with the widest range of compatible tools. Excellent build quality and extensive UK service network.

DeWalt DCH273 (18V SDS Plus)

Best for Heavy Masonry Work — ~£150 (body only)

18V XR brushless SDS Plus. 2.1J impact energy — higher than the DHR171, giving faster drilling through dense brick and concrete. SHOCKS Active Vibration Control reduces vibration at the handle. 3 modes: hammer drill, drill only, chisel. DeWalt XR 18V is the most widely adopted platform in UK professional construction. Compatible with XR FLEXVOLT 54V batteries for increased performance on heavy sustained drilling.

Milwaukee M18FHX (18V SDS Plus)

Best Build Quality — ~£180 (body only)

18V M18 FUEL brushless SDS Plus. Powerstate brushless motor, REDLINK PLUS intelligence (electronic overload protection). Extremely robust construction — Milwaukee is known for tool durability in harsh site conditions. 2.0J impact energy. The M18 FUEL platform includes arguably the best-in-class combi drill (M18FPD2) and impact driver (M18FID2) making it an excellent single-platform choice for an electrician wanting consistent quality across all cordless tools.

Cordless Combi Drill Recommendations

For Timber, Plasterboard, and Screwdriving

Buy your combi drill on the same platform as your SDS drill to share batteries. Top choices: Makita DHP484 (LXT), DeWalt DCD796 (XR 18V), or Milwaukee M18FPD2 (M18 FUEL). All are compact 18V brushless combi drills — under 1.5kg, high-speed mode for driving, low-speed high-torque mode for drilling. Brushless motor gives significantly more runtime and torque than equivalent brushed models.

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07 · Tools & Equipment Guide

Drilling Safety and Site Practice

Power tools in electrical installation work carry specific risks. Applying correct safe working practices reduces the risk of injury to you and damage to the installation:

Detect before drilling: Always use a cable detector before drilling into walls, floors, or ceilings. Use safe isolation before any work that could contact existing wiring.
RCD protection for power tools: All portable power tools used on site must be protected by a 30mA RCD at the supply point, or fed from a 110V CTE (Centre-Tapped Earth) transformer. Never plug a 230V power tool directly into a site supply socket without RCD protection.
PPE for drilling and chasing: Safety glasses or goggles (masonry chips and drill break fragments), dust mask (FFP2 minimum for concrete and silica- bearing materials), hearing protection for SDS drilling, and gloves. Silica dust from concrete and brick is a serious long-term lung hazard — respiratory protection is not optional.
Fire stopping: Any penetration of a fire compartment boundary (fire- rated wall, floor, or ceiling) must be sealed with appropriate intumescent fire stopping after cable installation. This is a Building Regulations requirement — not optional and not to be left to other trades.

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Frequently Asked Questions About Drills for Electricians

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Drill Guide for Electricians: SDS, Cordless, and Hole Saws for UK Electrical Work 2026

Key Takeaways

Choosing the Right Drill for Electrical Installation Work

Get the BS 7671 A4:2026 Cheat Sheet — free

SDS Plus vs SDS Max vs Standard Hammer Drill

Standard Keyless Chuck (Combi Drill)

SDS Plus

SDS Max

Cordless Voltage Ratings: 18V vs 54V Brushless

18V Brushless

54V / High-Power

Hole Saw Sets for Back Boxes and Cable Entries

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Core Drilling for Cable Containment

Always detect before drilling

Best Drills for Electricians 2026

Makita DHR171 (18V SDS Plus)

DeWalt DCH273 (18V SDS Plus)

Milwaukee M18FHX (18V SDS Plus)

Cordless Combi Drill Recommendations

Quote accurately for installation labour and materials

Drilling Safety and Site Practice

Document drilling locations and cable routes on site

Frequently Asked Questions About Drills for Electricians

What is the difference between SDS Plus and SDS Max?

Is 18V enough for SDS drilling through brick and block?

What hole saw do I need for surface back boxes?

What drill do I need for SWA cable entry through masonry walls?

How do I drill cleanly through ceramic tiles for electrical work?

Do I need a separate combi drill and SDS drill, or can one do both?

What is a brushless motor and why does it matter?

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