SWA Cable Gland Sizes
Gland selection chart for steel wire armoured cables to BS 5467
20S vs 20 — Not Interchangeable
Both use an M20 thread but the 20S has a smaller bore for thin cables (1.5–4.0 mm²). Using a standard 20 on a small cable gives a loose fit with poor armour clamping. Always check the chart below.
Gland Types
Indoor use only. Armour clamp and earth continuity, no weather seal.
Use For
Dry interiors, plant rooms, risers
Kit Parts
Single outer seal grips cable sheath. Standard for most outdoor work.
Use For
Outdoor, damp, condensation risk, wash-down areas
Kit Parts
Inner seal on bedding + outer seal on sheath. Prevents moisture wicking through armour.
Use For
Corrosive, chemical, immersion, food/beverage
Kit Parts
Gland Selection Chart
For XLPE/SWA/PVC cables to BS 5467. Always verify with calipers — OD varies ±5% by manufacturer.
| Cable (mm²) | 2-Core | 3-Core | 4-Core |
|---|---|---|---|
| 1.5 | 20S | 20S | 20S |
| 2.5 | 20S | 20S | 20S |
| 4.0 | 20S | 20S | 20 |
| 6.0 | 20 | 20 | 20 |
| 10 | 20 | 20 | 25 |
| 16 | 25 | 25 | 25 |
| 25 | 25 | 32 | 32 |
| 35 | 32 | 32 | 32 |
| 50 | 32 | 32 | 40 |
| 70 | 32 | 32 | 40 |
| 95 | 32 | 40 | 50S |
| 120 | 40 | 50S | 50 |
| 150 | 40 | 50S | 50 |
| 185 | 50S | 50 | 63S |
| 240 | 50 | 63S | 63 |
| 300 | 63S | 63 | 75S |
| 400 | 63S | 75S | 75 |
Thread Sizes & Clearance Holes
| Gland | Thread | Clearance Hole (mm) |
|---|---|---|
| 20S | M20 | 20.2–20.5 |
| 20 | M20 | 20.2–20.5 |
| 25 | M25 | 25.2–25.5 |
| 32 | M32 | 32.2–32.5 |
| 40 | M40 | 40.2–40.5 |
| 50S | M50 | 50.2–50.5 |
| 50 | M50 | 50.2–50.5 |
| 63S | M63 | 63.2–63.5 |
| 63 | M63 | 63.2–63.5 |
| 75S | M75 | 75.2–75.5 |
| 75 | M75 | 75.2–75.5 |
Torque Reference
Benchmark values — always follow the specific manufacturer's datasheet.
| Gland | Cap (Nm) | Body (Nm) |
|---|---|---|
| M20S | 2.5 | 8 |
| M20 | 3.0 | 12 |
| M25 | 5.0 | 25 |
| M32 | 5.0 | 40 |
| M40 | 5.0 | 50 |
| M50 | 10.0 | 70 |
| M63 | 10.0 | 100 |
Earthing & Bonding
SWA armour is an exposed conductive part — both ends must be bonded regardless of whether the armour is used as the CPC (BS 7671).
Earth Tags (Banjos)
- - Flat brass ring with lug
- - Can rotate during tightening — secure between two locknuts
- - Standard for metallic enclosures
Earthing Nuts
- - Replaces standard locknut
- - Biting teeth penetrate paint/plastic
- - Lower resistance, more vibration-resistant
In plastic enclosures, a fly-lead (green/yellow) must connect the earth tag or earthing nut to the enclosure's earth terminal. Size the fly-lead to match the cable core CSA.
IP Ratings by Gland Type
| Gland Type | IP Rating | Requires |
|---|---|---|
| BW | IP2X | Basic finger-safe protection only |
| CW | IP66 | Shroud + sealing washer at entry thread |
| E1W | IP66 / IP68 | Inner + outer seals correctly torqued |
Material Selection
| Material | Typical Use | Note |
|---|---|---|
| Brass | Standard domestic/commercial, indoor and outdoor | Default choice — cost-effective, good conductivity |
| Nickel-plated brass | AWA cable, mild corrosion environments | Prevents galvanic corrosion with aluminium armour |
| 316 Stainless steel | Food/beverage, chemical, marine | Resists dezincification and acidic wash-down |
Common Installation Mistakes
- - Wrong gland/armour match: using a wire-armour (W) gland on tape-armour (Z) or braid (X) cable — no mechanical retention or earth capacity
- - Loose fit on small cables: standard 20 gland on 1.5 mm² cable — armour wires not clamped, poor earthing
- - Insufficient thread engagement: minimum 5 full threads required; thick gland plates or earth tags can reduce engagement
- - Outdoor without shroud: water enters clamping area, armour rusts, earth resistance rises
- - Only one end bonded: both ends of SWA armour must be earthed to prevent induced voltages
- - Over-tightening: can crush insulation — always use manufacturer torque values
- - If between sizes, always go up to the larger gland