Cable gland size for armoured cable: gland and lug guide for sites in Gangtok, Rangpo and Namchi

Cable gland size for armoured cable is chosen by the cable’s outer diameter (OD), not by its sq mm size alone. Measure the OD over the outer sheath, pick a gland whose range covers it, and use a double compression gland for outdoor, damp or industrial sites. Then pick the lug by conductor size and material: copper lug on copper cable, bimetallic lug where aluminium cable lands on a copper busbar or terminal.

This guide is written for contractors and site engineers working in Gangtok, Rangpo, Singtam and Namchi, where rain, mist and humidity get into every badly sealed cable entry. The same advice applies across North Bengal, Bihar and Sikkim.

How do I find the right cable gland size for armoured cable?

Do not order glands by “4 core 25 sq mm” alone. The same size cable from two makers can have a different OD, and armoured, unarmoured, copper and aluminium cables of the same sq mm are all different thicknesses.

The simple method:

1. Measure the outer diameter of the actual cable on site (or read it from the cable maker’s datasheet for that exact cable).
2. Check the inner sheath (bedding) diameter too, if you are using a double compression gland — it grips there as well.
3. Pick the gland size whose clamping range covers both. A gland at the very edge of its range seals poorly.
4. Match the entry thread to the hole in the panel, DB, motor terminal box or junction box.

Gland makers say the same thing. One Indian maker’s guide puts it plainly: never select a gland by core size alone, always measure the actual OD (Cabex India).

Cable gland size chart: which gland for which cable?

The table below shows typical figures from an older published Polycab gland selection chart (Polycab chart, hosted by Prabhat Cables). Use it only to get a rough idea. Cable ODs change between makers and over time, so always confirm with the cable you actually have.

Armoured cable (4 core)	Cable OD in that chart	Single compression (commercial type)
16 sq mm	about 20 mm	1”
25 sq mm	about 23 mm	1 1/8”
35 sq mm	about 25 mm	1 1/8”
50 sq mm	about 28 mm	1 1/4”
95 sq mm	about 35 mm	1 1/2”
185 sq mm	about 48 mm	2”

Many glands today are sold in metric sizes by OD range instead. As an example, one maker lists a 25L gland for about 19–24.5 mm OD with an M25 thread, and a 32S for about 23–29 mm with an M32 thread (Cabex India). Different makers do not always agree on where a cable falls, which is one more reason to measure.

Single compression vs double compression gland: which one to use?

	Single compression	Double compression
Where it grips	Outer sheath only	Inner sheath (bedding) and outer sheath
Typical use	Indoor panels, dry and protected areas	Outdoor, damp, dusty and industrial sites
Armour clamping	Yes	Yes, with better sealing on both sides of the armour
Good for hill sites?	Only inside dry rooms	Yes — the usual choice

A single compression gland seals at one point, usually the outer sheath. A double compression gland seals at two points, the inner bedding and the outer sheath, and is the normal choice for outdoor and industrial work (Cabex India).

For Sikkim sites — pump houses, hotel plant rooms, hydro and road project feeders, outdoor street light and feeder pillars — we suggest double compression glands with weatherproof hoods or shrouds on outdoor entries. Moisture creeping along a cable into a panel is a common cause of tracking and trips in wet hill weather. This is general site practice, not a rule from any one standard.

Brass or aluminium gland? Nickel-plated brass is the common choice for Indian industrial work. Aluminium alloy glands are also made, and stainless steel is used for harsh or chemical areas (Cabex India). Heavy-duty brass glands are made to IS 12943 — Polycab’s chart lists its heavy-duty brass glands to this standard (Polycab chart).

Which lug should I use for copper and aluminium cable?

The lug must match the conductor size (sq mm), the conductor material, and the stud or bolt size of the terminal.

Cable conductor	Terminal / busbar	Lug to use
Copper	Copper or tinned terminal	Tinned copper lug
Aluminium	Aluminium terminal	Aluminium lug
Aluminium	Copper busbar or MCCB/ACB copper terminal	Bimetallic lug (aluminium barrel, copper palm)
Small flexible copper (control, panel wiring)	Screw terminal	Pin, fork or ring type crimp lug, or ferrule

Why bimetallic? When aluminium and copper touch directly, galvanic action corrodes the joint. A bimetallic lug has an aluminium barrel for the cable and a copper palm for the busbar, so the change from one metal to the other happens inside the lug (Axis). In humid places like Gangtok and Namchi, a wrong copper-to-aluminium joint can heat up and fail sooner.

Crimping vs soldering: how should lugs be fitted?

For power cables, lugs are normally crimped with the correct die for that lug size. A few practical points from site experience:

• Use the crimping tool and die made for that lug size. Hammering a lug flat is not a proper joint.
• Strip only as much insulation as the barrel needs. Bare conductor showing outside the lug is a fault waiting to happen.
• On aluminium conductor, clean the strands and use jointing compound if the lug maker asks for it.
• Tighten to the terminal maker’s torque and re-check after the first few days of load, especially on large cables.
• Use heat shrink or PVC sleeves for phase colour and protection.

Have a licensed electrician do the termination. A loose or wrong lug on an incomer can overheat and damage the MCCB or panel.

What should I write in the BOQ for glands and lugs?

Large buyers, project contractors and tender teams often lose time because glands and lugs are written as “glands – lot”. Itemise them instead. For each cable run, write:

• Cable: cores × sq mm, copper or aluminium, armoured or unarmoured, and cable OD if known (for example, “3.5 C × 95 sq mm Al armoured, OD __ mm”).
• Gland: single or double compression, material (brass / aluminium), weatherproof or not, entry thread size, and quantity — usually two per cable run (one at each end).
• Lug: material (copper / aluminium / bimetallic), conductor size, stud hole size, and quantity — one per core per end, plus spares.
• Accessories: earth tag or earthing for the armour, shrouds, sleeves, cable ties and markers.

For armoured cable, the gland also helps bond the armour to earth at the panel. Keep your earthing plan in step with this — see our guide on chemical earthing vs pipe earthing for hill sites.

If you are still choosing the cable itself, read armoured vs unarmoured cable first, then size glands and lugs to the cable you finalise.

Why buy glands, lugs and cable from one dealer?

When the cable, glands and lugs come from one place, the sizes are checked together before dispatch. That avoids the most common site problem — a drum reaches Rangpo or Singtam and the glands do not fit the actual cable OD, or the lugs are copper when the cable is aluminium.

Shree Shyam Suppliers is an authorised dealer for Havells, Lauritz Knudsen (L&T) and Mescab, and also deals in Polycab, KEI and RR Kabel. We can cut cable to length and send an itemised quote with matching glands and lugs on WhatsApp. You can browse our cables and wires range too.

Price: gland and lug prices depend on size, material (brass, aluminium, copper, bimetallic), type (single or double compression, weatherproof), brand and quantity. WhatsApp us for today’s rate.

Ordering tip

Send Shree Shyam Suppliers your cable schedule on WhatsApp with:

• each cable’s cores, sq mm, copper or aluminium, armoured or not, and OD if you have it;
• gland type (single or double compression), material and thread size;
• lug type and stud size for each termination;
• quantities, preferred brand, and your site location.

We will reply with an itemised quote. We deliver across North Bengal, West Bengal, Sikkim, Bihar, Bhutan and Nepal.