By Thunderbolt Electromech India Pvt. Ltd. — Delhi-based Distributor& supplier of Dowells, comet, HMI, Diamond and MIC cable glands

📞 +91-9911886655 | ✉️ info@thunderboltelectromech.com | 🌐 thunderboltelectromech.com | 📍 Shop No. 3538, Sitaram Bazar Rd, Bazar Sirkiwalan, Chawri Bazar, Chandni Chowk, Delhi – 110006

Quick Answer: Choose an armoured cable gland whenever the cable itself carries steel or aluminium wire armour — the gland must clamp that armour to provide both mechanical retention and earth continuity, not just seal the outer sheath. Choose an unarmoured gland for cables with no armour layer, typically indoor panel wiring with limited mechanical risk. Getting this wrong isn’t a small mismatch — an unarmoured gland on armoured cable leaves the armour unclamped, and unclamped armour means no verified earth fault path. A genuine Cable Gland Supplier India should ask which cable construction you’re terminating before quoting a size.

Introduction

Ask most procurement teams what separates an armoured cable gland from an unarmoured one, and you’ll get a shrug followed by “armoured is for outdoor, right?” That’s not wrong exactly, but it misses the actual engineering reason the distinction exists — and missing that reason is how sites end up with glands that look correctly installed while quietly failing at the one job that matters most during a fault.

An unarmoured gland only has to do two things: grip the cable and keep water out. An armoured gland has to do those two things and a third, far more consequential job — clamp the cable’s steel or aluminium armour firmly enough to carry fault current safely to earth. Skip that third function, or get the clamp geometry wrong, and the gland can look perfectly sealed from outside while offering zero protection the day something actually goes wrong inside the panel.

This guide walks through what actually separates armoured and unarmoured cable gland selection — not just “which one costs more” — using the engineering reasoning that most buying guides skip entirely, and covering Dowells, Comet, HMI, Diamond, and MIC ranges as supplied by Thunderbolt Electromech India Pvt. Ltd.

What Makes a Cable “Armoured” in the First Place

Before choosing a gland, it helps to be precise about what armour actually is. Steel wire armoured (SWA) cable — and its aluminium wire armoured (AWA) counterpart — adds a layer of spiral-wound metal wire between the inner and outer sheath, sitting outside the cable’s insulation but under the final outer jacket (Source: Wikipedia, “Armoured cable,” cross-referenced against manufacturer construction data — Direct source found). It’s not decorative. It exists to protect the conductors from impact, crushing, and rodent damage — the exact hazards a buried cable or a cable running through a busy plant floor actually faces.

Unarmoured cable skips this layer entirely. It’s lighter, more flexible, and cheaper, but it depends entirely on its outer sheath and, where used, external conduit or trunking for mechanical protection.

What Makes a Cable Gland “Armoured” vs “Unarmoured”

The physical difference inside the gland is small in size but large in consequence. An armoured gland includes an internal clamping cone or ring, positioned specifically to sit under the armour wires and compress them against the gland body as the cable is drawn into the entry (Source: Elec-Mate, “Armoured Cable Installation UK | SWA Cable Guide” — Direct source found). An unarmoured gland has no such component — there’s nothing to clamp, because there’s no armour layer to clamp onto.

This is why a single-compression unarmoured gland, forced onto armoured cable, doesn’t fail loudly. It physically fits. The outer sheath gets gripped and sealed exactly as it would on unarmoured cable. What’s missing is any mechanical connection to the armour wires themselves — they sit loose inside the gland, uncompressed, electrically disconnected from the gland body and, by extension, from earth.

The Real Reason Armour Needs a Different Gland: Earth Continuity, Not Just Grip

This is the point most cable gland buying guides skip entirely, and it’s worth sitting with, because it changes how you should think about the whole decision.

Armour isn’t just mechanical protection. In many installations, it doubles as the circuit protective conductor — the path fault current takes back to earth when something goes wrong. Where armouring is used as the protective conductor, it has to meet the same electrical continuity and cross-sectional area requirements as any other earth conductor, under the same principle used in India’s own earthing code and mirrored explicitly in UK wiring regulations (Source: Voltimum UK, “Earthing the armour of steel wire armoured cable,” citing BS 7671 Regulation 411.3.1.1 and 543.2.5 — Direct source found).

Here’s the engineering consequence that rarely gets spelled out: if the armouring is interrupted — say, by running the cable through a non-metallic gland or enclosure with no separate earth continuity path — downstream metallic parts of the installation can rise to line voltage under fault conditions, and that voltage can remain completely undetected until someone touches a part that should have been safely earthed (Source: Voltimum UK — Direct source found). That’s not a sealing failure. That’s a shock hazard hiding behind a gland that looks correctly installed.

How the gland actually maintains this path?

 A correctly fitted armoured gland provides earth continuity from the armour termination through to the equipment body — either via a metallic enclosure directly, through a gland plate, or via an external earth tag (sometimes called a banjo washer) fitted between the gland body and the enclosure face, with a separate green/yellow conductor run from the tag to the earth bar (Source: ETS Cable Components, “Earthing Requirements of Cable Glands Used on SWA Cables” — Direct source found).

What goes wrong when the geometry is off?

Field documentation from cable gland manufacturers identifies three specific failure patterns when an armoured gland is fitted with the wrong internal geometry for the cable: the clamping cone fails to grip the armour at all (meaning zero earth continuity despite a gland that looks fully tightened), the outer sheath ends up seated on the wrong side of the gland relative to the enclosure (compromising the gland body’s grip on the sheath), or the inner cores get stretched against the gland body and chafe against it — creating an insulation damage and live-to-earth fault risk of its own (Source: squote, “SWA Cable Glanding: Gland Selection and Earthing” — Direct source found).

None of these three failure modes are visible from outside a finished installation. They only show up during a continuity test, or worse, during an actual fault.

BW vs CW Armoured Gland Types: Indoor vs Outdoor

Armoured glands aren’t one product — the two most common types differ specifically by environmental exposure:

BW type glands are designed for indoor use on SWA cable, providing mechanical retention and armour earth continuity without the additional outer sealing that outdoor exposure demands.

CW type glands add an environmental seal — typically to IP66 — across the cable’s outer sheath in addition to the armour clamping function, making them the correct choice for outdoor and weatherproof installations (Source: ETS Cable Components, “Armoured Cable Glands” — Direct source found).

Specifying a BW-type gland for an outdoor termination is a common, avoidable mistake — the armour clamping works identically, but the installation lacks the environmental sealing an outdoor entry point actually needs, and moisture finds its way in through exactly the point the gland was meant to protect.

Single Compression vs Armoured Double Compression: How They Differ Mechanically

It’s worth being precise here, because the terms get used loosely. A single compression gland seals at one point — typically the outer sheath — and is the correct choice for unarmoured cable in low-vibration indoor settings. A double compression armoured gland seals and clamps at two distinct points: the inner cone compresses around the armour wires, and a second compression point grips the outer sheath independently.

This dual-point construction is what gives armoured double compression glands meaningfully higher pull-out resistance and vibration tolerance than a single compression gland can offer — the armour clamp anchors the cable mechanically, while the outer seal handles environmental protection separately. Trying to get both functions from a single compression point, by forcing an unarmoured single-compression gland onto armoured cable, compromises both jobs at once rather than doing either one adequately.

Comparison Table: Armoured vs Unarmoured Cable Glands

Feature	Unarmoured Cable Gland	Armoured Cable Gland
Internal clamping cone	Not present	Present — clamps armour wires directly
Earth continuity function	None (relies on separate CPC)	Provides verified path from armour to earth bar
Compression points	Single (outer sheath only)	Dual (armour clamp + outer sheath seal)
Typical gland type	Single compression	BW (indoor) or CW (outdoor, IP66-rated)
Best suited cable	Unarmoured, PVC/XLPE insulated	SWA / AWA armoured cable
Mechanical pull-out resistance	Moderate	High
Vibration tolerance	Limited	Strong, particularly with correctly torqued armour clamp
Typical application	Indoor panels, control cabinets, low-risk indoor runs	Underground runs, outdoor switchyards, high-vibration machinery, buried and duct-routed feeders
Failure risk if mismatched	Sheath grip may be inadequate for heavier cable	Armour left unclamped — no earth continuity, undetected shock hazard

When to Choose an Armoured Cable (and Gland)

Underground and duct-buried runs. Buried cable faces impact risk from digging, settling ground, and rodent activity that unarmoured cable simply isn’t built to survive over a multi-year service life.

Outdoor switchyards and substations. Exposure to physical impact, temperature cycling, and general wear makes armoured cable the standard specification for outdoor HT and LT feeders.

High-vibration machinery connections. Motors, compressors, and process equipment subject cabling to continuous mechanical stress that unarmoured cable and single-compression glands aren’t rated to absorb long-term.

Any installation using the armour itself as the protective conductor. Where design intent relies on the armour doubling as the CPC, armoured cable with a correctly matched, properly earthed gland isn’t optional — it’s the entire safety mechanism for that circuit.

When Unarmoured Cable (and Gland) Is the Right Call

Indoor panel and control cabinet wiring. Where cable runs stay entirely within a protected enclosure, away from impact and mechanical stress, unarmoured cable with a standard single-compression gland is the appropriate, cost-effective choice — not a corner cut.

Short, protected indoor runs within conduit or trunking. When mechanical protection comes from the containment system itself rather than the cable construction, armour becomes redundant weight and cost.

Lighting circuits and low-risk distribution wiring. Genuinely low mechanical-risk applications rarely justify the added cost and installation complexity of armoured cable and glanding.

Cable Gland Supplier India — Getting the Armour Clamp Geometry Right

This is exactly where a technically capable Cable Gland Supplier India earns their relationship with an engineering team, rather than just moving stock. Getting armour clamp geometry right depends on matching the gland’s internal cone dimensions to the specific cable’s armour wire diameter and layer construction — not just its overall outer diameter. Two SWA cables at the same nominal cross-section can carry different armour wire gauges depending on manufacturer, and a gland sized purely off the cable’s OD chart without checking the armour specification can leave the cone unable to seat correctly against the actual wires.

A supplier who understands this asks for the cable’s specific armour construction — wire diameter and layer count — before confirming gland size, the same way Dowells Cable Glands and HMI Cable Glands are specified for critical utility and EPC work precisely because their armoured ranges are built to the tighter tolerances this clamp geometry demands. Thunderbolt’s earlier cable gland size selection guide covers the outer-diameter side of this calculation in detail — see Cable Gland Size Selection Explained: The Engineering Formula Most Buyers Ignore — but armour geometry is the layer that OD alone doesn’t capture, and it’s the layer this guide exists to explain.

Common Installation Mistakes Specific to Armoured Gland Termination

Mistake 1 — Over-tightening the armour clamp.

The clamp needs to grip the armour wires firmly, not crush them. Over-tightening can shear individual wires, reducing the cross-sectional area actually available to carry fault current even though the gland appears securely fastened.

Mistake 2 — Skipping the continuity test after installation.

A gland that’s mechanically tight isn’t automatically providing verified earth continuity. Testing armour-to-earth continuity with a low-resistance ohmmeter after termination — not assuming a tight gland equals a good path — catches clamp geometry problems before the circuit is energised (Source: Elec-Mate — Direct source found).

Mistake 3 — Forgetting the earth tag on non-metallic enclosures.

Where the gland terminates into a plastic or GRP enclosure rather than a metal one, the enclosure body itself provides no earth path — an external earth tag with a separate conductor to the earth bar becomes mandatory, not optional, and it’s frequently the step that gets missed on non-metallic installations.

Mistake 4 — Ignoring minimum bend radius near the gland.

Armoured cable typically needs a minimum bend radius around eight times its overall diameter; forcing a tighter bend close to the gland entry can splay the armour wires or crack internal insulation, undermining both the mechanical and electrical integrity the gland was meant to preserve (Source: Central Wires, “Armoured Cable | Steel Wire Armoured SWA Cable” — Direct source found).

Mistake 5 — Using an unarmoured gland “because it fits.”

Covered at length above — physical fit is not the same as functional correctness, and this is the single most consequential mismatch covered in this entire guide.

Dowells, Comet, HMI, Diamond & MIC: Matching the Range to Armoured or Unarmoured Work

Thunderbolt Electromech India Pvt. Ltd. stocks both premium and mid-range brands, and the armoured-versus-unarmoured decision maps onto that range in a specific, practical way.

Dowells and HMI hold the tightest manufacturing tolerances in Thunderbolt’s range, which matters directly for armoured clamp geometry on critical utility, EPC, and substation work — installations where a continuity test failure after commissioning isn’t just inconvenient, it can delay energisation of an entire feeder.

Comet Cable Glands offer reliable armoured and unarmoured options for general industrial automation and panel-building work, where consistent sealing and armour clamping matter but the project doesn’t demand the same certification depth as a utility contract.

Diamond Cable Glands and MIC glands cover the unarmoured, indoor-panel end of the spectrum well — commercial buildings, OEM equipment, and control cabinets where cable stays protected and mechanical risk is genuinely low.

The mistake to avoid is applying one brand tier across an entire project regardless of cable type. A site running both buried armoured feeders and indoor unarmoured panel wiring often gets better value specifying Dowells or HMI for the armoured runs specifically, and Diamond or MIC for the indoor unarmoured wiring, rather than standardising on one tier for everything.

How a Cable Gland Supplier India Helps You Avoid Earth-Continuity Failures

A genuine Cable Gland Supplier India relationship pays for itself most clearly on exactly the failure mode this guide has focused on — earth continuity that looks fine on installation day and fails silently later. The right supplier should be able to:

• Ask for armour wire diameter and layer count, not just cable OD, before confirming a size
• Recommend BW versus CW type correctly based on indoor or outdoor exposure
• Explain the earth tag requirement for non-metallic enclosures without needing to look it up
• Stock both armoured and unarmoured ranges across multiple brand tiers, so the right product is available regardless of which type a given site needs that week
• Flag the continuity-testing step as part of a proper handover, not leave it to the installer to remember unprompted

Common Customer Problems and Solutions

Problem: “We passed our IP rating inspection, but our earth continuity test failed.”

This is the exact scenario this guide has walked through — a gland that seals well against water can still leave the armour clamp under-gripping the wires. Re-checking the clamp cone against the actual armour wire diameter, and re-testing continuity after correction, resolves this without needing to replace the entire termination.

Problem: “Our contractor used unarmoured glands on our armoured feeder cable to save time.”

This happens more often on fast-track projects than most engineers would like to admit — the gland physically fits the cable’s outer diameter, so it passes a visual check. The fix is re-terminating with correctly specified armoured glands and running a continuity test across every affected termination, not just the ones that raise obvious concern.

Problem: “We don’t know whether our enclosure needs an earth tag or not.”

If the enclosure body is solid metal and directly bonded to the gland, a separate earth tag often isn’t required. If it’s plastic, GRP, or any non-metallic material, an earth tag with its own conductor to the earth bar is standard practice, not an optional extra.

Problem: “Our armoured cable keeps failing continuity tests even with a correctly rated gland.”

Beyond clamp geometry, check for over-tightening damage to the armour wires themselves, or a bend radius violation close to the gland that’s stressed the armour layer during installation — both covered in the mistakes section above.

Case Study: A Delhi NCR Data Centre’s Buried Feeder Termination

A data centre facility in Delhi NCR running buried 11kV feeder cable to its outdoor transformer yard experienced an unexpected earth fault loop impedance failure during pre-commissioning testing — despite every gland on the run appearing fully tightened and passing a visual inspection. The design used SWA cable specifically so the armour could serve as part of the protective conductor path, reducing the need for a separate external earth conductor along the entire buried run.

Investigation traced the failure to two of the twelve terminations, where a general-purpose double compression gland — rated correctly for the cable’s outer diameter but not specifically verified against that particular cable batch’s armour wire gauge — had been fitted. The clamping cone was seating against the outer sheath rather than gripping the armour wires cleanly underneath it, leaving those two terminations with dramatically higher resistance to earth than the other ten.

The facility’s electrical contractor replaced the two mismatched terminations with Dowells armoured glands specifically verified against the cable manufacturer’s armour wire specification sheet, rather than the general OD chart alone, and re-ran continuity testing across all twelve terminations before sign-off. The corrected terminations brought earth fault loop impedance well within the required range, and the facility built armour-specification verification into its termination checklist for all subsequent expansion phases — a small procedural change that closed a gap invisible to any visual inspection.

Frequently Asked Questions

Do I need a special gland for armoured cable, or can I use a normal one?

Yes, you need a gland specifically designed for armoured cable — one with an internal clamping cone that grips the armour wires. A standard unarmoured gland will physically fit onto armoured cable’s outer sheath, but it leaves the armour unclamped, with no verified earth continuity path — a gap that won’t show up in a routine visual check.

What actually happens if SWA armour isn’t earthed properly?

Under fault conditions, downstream metallic parts connected to that circuit can rise to a dangerous voltage without any visible warning, since the fault current has no safe, low-impedance path back to earth. This is a genuine shock hazard, not just a compliance technicality — a question that comes up frequently in electrician forums precisely because the risk isn’t obvious from outside a finished installation.

Is a double compression gland the same thing as an armoured gland?

Not exactly — double compression describes having two separate sealing/clamping points, and while most armoured glands are double compression by design (one point for the armour, one for the outer sheath), a double compression gland built for heavy unarmoured cable exists too. The armour-specific clamping cone is what makes a gland genuinely “armoured,” not the compression count alone.

Can armoured cable be terminated into a plastic enclosure?

Yes, but it needs an earth tag (sometimes called a banjo washer) fitted between the gland body and the enclosure, with a separate green/yellow conductor run to the earth bar — because a non-metallic enclosure can’t itself carry the earth continuity path the way a metal enclosure body can.

Why does my correctly sized armoured gland still fail a continuity test?

The most common causes are a clamping cone that doesn’t match the specific cable’s armour wire diameter (even when the overall gland size is correct for the cable’s OD), over-tightening that’s sheared or damaged individual armour wires, or a bend radius violation near the gland that’s stressed the armour layer during installation.

Do I need armour continuity at both ends of the cable, or just one?

This depends on whether the armour is being used as the sole protective conductor or working alongside a separate core used as CPC. Where the armour is the only earth path, both ends generally need to be earthed to maintain continuity along the full run; where a separate CPC core exists, practice varies — this is exactly the kind of project-specific detail worth confirming with a qualified electrical engineer rather than assuming a single rule applies everywhere.

Why Choose Thunderbolt as Your Cable Gland Supplier India

Thunderbolt Electromech India Pvt. Ltd. is a Delhi-based Cable Gland Supplier India engineers and EPC contractors turn to specifically because the armoured-versus-unarmoured decision gets treated as an engineering question, not a catalogue lookup. The stock spans:

• Armoured double compression glands from Dowells, Comet, and HMI, specified for buried feeders, outdoor switchyards, and high-vibration machinery connections
• Unarmoured single compression glands from Diamond and MIC, suited to indoor panel and control cabinet wiring
• Both BW (indoor) and CW (outdoor, IP66-rated) armoured gland types, so the environmental exposure question gets answered correctly alongside the armour question

For a broader look at how Thunderbolt’s full cable gland range is selected across sizing, IP rating, and installation environment, see the complete guide, Cable Gland Supplier India: 15 Expert Tips to Choose the Right Cable Gland for Industrial Projects, and browse the full stocked range on the Cable Gland category page.

Cable Gland Supplier India: Final Checklist Before You Order

Before placing an order for armoured or unarmoured cable glands, confirm:

• Cable construction — armoured (SWA/AWA) or unarmoured, confirmed from the cable datasheet, not assumed from the application alone
• Armour wire diameter and layer count, if armoured, not just overall cable OD
• Indoor or outdoor installation, to select BW or CW type correctly
• Whether the armour is intended to serve as the protective conductor, or whether a separate CPC is used
• Enclosure material — metallic or non-metallic — to determine whether an earth tag is required
• Minimum bend radius clearance near the gland entry point
• A planned continuity test after termination, before the circuit is energised

For related buying questions on sizing and IP protection specifically, Thunderbolt’s guides on Cable Gland Size Selection, What Size Cable Gland Do I Need for My Project?, and IP66, IP67, IP68 or IP69? How to Select the Right Cable Gland Protection Rating cover the questions this guide doesn’t focus on directly. For the installation mistakes that cause water ingress specifically — a related but distinct failure mode from the earth-continuity focus of this guide — see Why Cable Glands Fail in Industrial Projects: 17 Installation Mistakes That Cause Water Ingress.

Contact Thunderbolt Electromech India Pvt. Ltd.: 📍 Shop no. 3538, Sitaram Bazar Rd, Bazar Sirkiwalan, Chawri Bazar, Chandni Chowk, Delhi, 110006 📞 +91-9911886655 ✉️ info@thunderboltelectromech.com

Conclusion

Armoured and unarmoured cable glands solve different problems, and treating them as interchangeable based on whether the cable “fits” is where most earth-continuity failures actually start. Unarmoured glands seal and grip a sheath; armoured glands do that and clamp the armour wires themselves into a verified, testable path to earth — a function that’s invisible from outside a finished installation and only shows up in a continuity test, or worse, during an actual fault. The decision comes down to cable construction, installation environment, and whether the armour is doing electrical work as a protective conductor, not just mechanical work as physical protection. Thunderbolt Electromech India Pvt. Ltd. supplies both armoured and unarmoured ranges across Dowells, Comet, HMI, Diamond, and MIC, matched to the actual cable specification rather than sold as a one-size answer — because on this particular product, getting the match wrong doesn’t just risk a leak. It risks a fault path that was never really there. Call +91-9911886655 or write to info@thunderboltelectromech.com to get the right gland matched to your cable’s actual construction before your next termination.