16mm armoured cable: a complete buying guide for UK installations

What is 16mm armoured cable?

16mm armoured cable is a low-voltage power cable with a 16mm² conductor cross-section, protected by a layer of galvanised steel wire armour (SWA) or aluminium wire armour (AWA), rated at 600/1000V and designed for direct burial, outdoor or industrial power distribution.

In practical terms, the 16mm² conductor size sits in a commercially sweet spot. It is robust enough to handle the main feeder loads common in commercial buildings, solar PV installations and agricultural pumping circuits, yet compact enough to pull through standard 50mm conduit without excessive effort. The armoured sheath transforms what would otherwise be a fragile XLPE or PVC-insulated cable into a mechanically resilient system that resists rodent damage, accidental dig-ins and the compressive stresses of direct burial.

South African electrical engineers typically encounter this specification written as 16mm SWA cable or simply armoured cable 16mm in tender documents. The full product description on a local manufacturer's data sheet will usually read something like: "16mm² 3-core copper XLPE/SWA/PVC low voltage armoured electrical cable, SANS 1507." That string of descriptors tells you the conductor size, core count, conductor material, insulation type, armour type and applicable standard — each element matters when you are comparing quotes from competing suppliers.

For a deeper technical background on how armoured cable is constructed and classified globally, the armoured cable overview on Wikipedia provides a useful reference.

Why 16mm² is such a common specification in South Africa

Real-world project experience confirms that the 16mm² rating appears repeatedly in South African tender documents for a specific reason: it aligns neatly with the 63A and 80A MCB breaker sizes that dominate LV distribution boards in commercial and light-industrial premises. Solar inverter manufacturers also frequently specify 16mm copper armoured cable for DC combiner-to-inverter runs and inverter-to-distribution-board AC feeds, because the current range matches standard residential and SME inverter outputs between 10 kW and 30 kW. With South Africa's aggressive renewable energy build-out under the IRP 2025 framework — a programme representing approximately R2.23 trillion in planned energy infrastructure investment — demand for this particular size has grown sharply since 2024 and shows no sign of plateauing through 2026.

Single-core versus multi-core: a critical distinction upfront

One point that confuses many buyers is armour material selection for single-core versus multi-core cables. Steel wire armour is suitable for multi-core cables. For single-core applications, aluminium wire armour (AWA) must be used instead. The reason is electromagnetic: when AC current flows through a single conductor, the steel armour of an SWA cable acts like a shorted transformer secondary, inducing eddy currents that generate heat and create a serious fire risk. AWA, being non-ferromagnetic, avoids this problem. Specifying SWA on a single-core installation is not merely suboptimal — it is a safety hazard and non-compliant under South African wiring rules.

SANS 1507 compliance: what South African buyers must know

Any 16mm armoured cable purchased for a South African installation must comply with SANS 1507, which is the national standard governing electric cables with extruded solid dielectric insulation for fixed installations. Non-compliant cable is not only a legal liability — it will fail inspection by the electrical installation authority and invalidate the Certificate of Compliance (CoC) that is legally required before any new or altered installation is energised.

What SANS 1507 actually specifies

SANS 1507 sets minimum requirements for conductor resistance, insulation thickness, armour wire dimensions and diameter, sheath material properties, voltage test levels (3.5 kV AC for 1 kV-rated cables), and marking requirements. A compliant 16mm copper armoured cable drum will carry clear drum-end labelling showing the SANS 1507 designation, the manufacturer's name, the cable construction description, the nominal conductor cross-section (16mm²), the rated voltage (0.6/1 kV) and the drum length in metres. If a supplier cannot produce a SANS 1507 test certificate for the batch you are purchasing, that is a significant red flag — particularly given the 2025–2026 influx of non-compliant imported cable competing on price in the South African market.

"The armour of an SWA cable serves a dual function: it provides mechanical protection against physical damage and, when correctly terminated and earthed at both ends, it constitutes the circuit protective conductor (CPC) for the installation." — ECA(SA) Technical Guidance, Ronald Hardie Pr.Eng

SANS 1507 versus BS 5467: understanding the relationship

SANS 1507 is harmonised with BS 5467 (the British Standard for armoured cables with thermosetting insulation), which is why South African and UK-origin cables often appear interchangeable in specification documents. The voltage rating, construction sequence and test requirements are substantially aligned. However, SANS 1507 includes South Africa-specific requirements for labelling in local languages and specific temperature reference conditions (30°C ambient air, 20°C ground temperature) that differ from British Standard defaults. When sourcing cable for a South African project, always request SANS 1507 certification explicitly, even if a supplier offers BS 5467-certified product — the two certifications are not automatically interchangeable for CoC purposes.

Current ratings for 16mm armoured cable: a three-scenario comparison table

The rated current-carrying capacity of 16mm armoured cable is not a single fixed number — it varies meaningfully depending on installation method, ambient temperature and grouping. This is the detail most competing resources get wrong by quoting only one headline figure. Based on SANS 10142-1 reference conditions (30°C air, 20°C ground, thermal resistivity 1.2 K·m/W), the table below shows derating-adjusted values for the three installation scenarios most common on South African sites.

Installation method	16mm² copper (A)	16mm² aluminium (A)	Notes
Direct buried in ground (single circuit)	~95 A	~75 A	600mm depth, 20°C soil, no grouping
In PVC conduit in ground	~80 A	~63 A	Conduit reduces heat dissipation
In free air / cable tray	~87 A	~68 A	30°C ambient, single circuit

Why derating matters on South African sites

South Africa's summer temperatures regularly push ambient conditions well above the SANS reference of 30°C. In a Gauteng summer, cable tray temperatures in a plant room can reach 45°C or higher. At that ambient, the free-air rating of a 16mm copper armoured cable drops to approximately 70A — a meaningful reduction that, if ignored, leads to chronic overloading. The derating factor for 45°C is approximately 0.87 applied to the 30°C base value. Always confirm actual site ambient conditions before finalising conductor sizing, and build in a 20% safety margin for circuits that will run at sustained load for extended periods.

Voltage drop: the check that is often skipped

Current rating is only half the sizing equation. On long runs — anything over 50 metres — voltage drop becomes the binding constraint. A 16mm² copper conductor has a resistance of approximately 1.15 mΩ/m at 70°C. On a 100-metre three-phase run at 80A, the voltage drop calculates to roughly 9V, or about 3.9% of a 230V phase voltage. SANS 10142-1 limits voltage drop to 5% for most final circuits. That margin gets consumed quickly on farm irrigation runs or solar array feeders that can span several hundred metres. In those cases, stepping up to 25mm² is more economical than experiencing nuisance tripping or equipment damage.

Copper vs aluminium conductors: which 16mm armoured cable is right for your project?

The choice between 16mm copper armoured cable and 16mm aluminium armoured cable comes down to three factors: cost, current capacity and jointing complexity. Copper consistently outperforms aluminium on electrical performance, but aluminium has a compelling price advantage that makes it the preferred choice for long rural distribution runs where budget is tight.

Performance and cost comparison

Attribute	16mm² copper	16mm² aluminium
Current rating (direct buried, A)	~95 A	~75 A
Conductor resistance (mΩ/m at 20°C)	1.15	1.91
Approximate ZAR price per metre (2026)	R95–R135	R60–R85
Jointing difficulty	Standard lugs	Bi-metal lugs required
Typical application in SA	Industrial, solar, buildings	Eskom reticulation, rural

A practical note from real-world project experience: aluminium conductors are more susceptible to oxidation at termination points, which increases contact resistance over time if bi-metal lugs and anti-oxidant compound are not used. In corrosive coastal environments — KwaZulu-Natal and the Western Cape coast, for instance — copper conductors are almost always the professional recommendation despite the higher upfront material cost. The extra spend is minor compared to the cost of a fault-tracing exercise three years into a project's lifecycle.

When aluminium is the logical choice

That said, aluminium armoured cable is entirely appropriate for long rural reticulation runs where the total cable bill runs into tens of thousands of rands, the installation is straightforward trench work, and the terminations will be made by a qualified artisan who understands bi-metal jointing. Agricultural water pumping projects on Karoo farms are a classic example. The 20–30% cost saving per metre on a 500-metre run is difficult to argue against, provided the sizing calculation accounts for aluminium's lower conductivity — which typically means stepping up one or two conductor sizes to match the current-carrying performance of copper.

2-core, 3-core and 4-core: choosing the right configuration

Selecting the correct core count is not simply a matter of counting phases. The right choice depends on the earthing system of the installation, whether a neutral conductor is required and what protection philosophy has been adopted. Getting this wrong means ordering cable that cannot be legally used for the intended circuit — a costly mistake when you are working against a project deadline.

Core count selection guide

Core count	Typical South African application	Notes
16mm 2 core armoured cable	Single-phase supply to outbuildings, street lighting, solar DC runs	Line + neutral; armour serves as CPC
16mm 3 core armoured cable	Three-phase motors, pumps, DB-to-DB feeds without separate neutral	Three phases; armour as CPC (TN-S systems)
16mm 4 core armoured cable	Three-phase + neutral distribution: commercial buildings, Eskom metering feeds	Most common for building services in SA
16mm 5 core armoured cable	Three-phase + neutral + separate earth (TN-S, sensitive equipment)	Less common; used where IT systems require clean earth

Why do so many contractors default to 4-core without checking first? The 3-core and 4-core debate centres on whether the installation uses a TN-S earthing system (separate neutral and earth throughout) or a TN-C-S system (combined PEN conductor). In most South African commercial and industrial installations, a 4-core cable — 16mm 3 core armoured cable with an added neutral — is specified, with the armour providing the protective earth. This is the configuration Eskom and most network operators recognise as standard for metered supply points.

Concentric vs SWA for single-phase metered connections

One configuration worth noting for South African residential and small commercial connections is concentric service cable, which many local utilities still use for last-mile supply. However, for sub-distribution from a main DB to a secondary DB — the application where 16mm 2 core armoured cable is most commonly specified — SWA is consistently preferred for mechanical robustness, particularly for underground runs across vehicle crossings and landscaped areas.

16mm armoured cable price in South Africa: ZAR market rates and cost factors

Transparent pricing is one of the most searched-for pieces of information in this category, yet most suppliers avoid publishing it. Based on 2026 market observations from South African electrical wholesale distributors and online platforms, the following ZAR per-metre ranges represent typical counter prices for SANS 1507-compliant cable purchased in 100-metre drum lots.

2026 ZAR price indicative ranges

Cable type	Core count	Copper ZAR/m	Aluminium ZAR/m
16mm SWA XLPE/PVC	2-core	R75–R100	R50–R70
16mm SWA XLPE/PVC	3-core	R95–R125	R65–R88
16mm SWA XLPE/PVC	4-core	R120–R160	R80–R110

These figures are indicative counter prices inclusive of VAT for standard stock items. Actual prices vary with copper commodity rates (LME copper), rand/dollar exchange rate, manufacturer (Aberdare, Alvern and various importers), and order volume. Bulk orders of 500 metres or more typically attract a 5–12% discount. It is worth noting that armoured cable price South Africa listings on e-commerce platforms sometimes reflect import-grade product without SANS 1507 certification — always confirm compliance before signing a purchase order.

What drives price volatility in 2026

The rand has remained volatile against the dollar through 2025–2026, and copper prices on the LME have been elevated by global energy transition demand. South African cable manufacturers face dual pressure: rising raw material costs and competition from lower-cost imported cable, some of which does not meet SANS 1507 tolerances. The South African government is actively pursuing local content requirements for state infrastructure procurement, which could influence supply dynamics and pricing in the medium term. For projects where budget certainty matters, locking in cable pricing at tender stage via a confirmed supplier quotation is strongly recommended rather than relying on indicative price lists.

How to install 16mm armoured cable: bending radius, glands and earthing

Correct installation practice for underground armoured cable is where many otherwise well-specified projects fall apart. The cable can be perfectly compliant with SANS 1507, but if it is terminated with the wrong gland, bent beyond its minimum radius or left unearthed at one end, the installation is both non-compliant and potentially dangerous. The following steps reflect current best practice under SANS 10142-1 for South African LV installations.

Step-by-step installation process

1. Survey and mark the route. Confirm the trench depth — minimum 600mm under general ground for LV cable per SANS 10142-1, increasing to 900mm under vehicle crossings.
2. Check minimum bending radius. For 16mm SWA cable, the minimum bending radius during installation is typically 8× the overall cable diameter (approximately 120–140mm for a standard 4-core 16mm² cable). Exceeding this risks armour wire damage and insulation cracking.
3. Prepare the trench bed. Lay a 75mm sand or sifted soil bed. Place a layer of protective tiles or bricks over the cable before backfilling, and install a warning tape 150–200mm above the cable.
4. Pull the cable. Use a pulling sock on the armour, not the conductor ends. Avoid exceeding the maximum pulling tension — for 16mm copper SWA, typically around 1.5 kN for a 4-core cable. Excessive tension deforms the conductor and armour.
5. Select the correct armoured cable termination gland. For outdoor or underground entry, use a brass or stainless steel SWA gland rated IP68. The gland must clamp the armour wires positively to achieve electrical continuity. A plastic gland is not acceptable for a compliant SWA termination where the armour is serving as the CPC.
6. Earth the armour at both ends. SANS 10142-1 and ECA(SA) technical guidance are unambiguous: the SWA armour must be bonded to the main earthing terminal (MET) at the supply end and to the consumer's earth bar at the load end. Earthing at one end only defeats the armour's function as a CPC and leaves the installation non-compliant.
7. Apply heat-shrink end caps. Immediately after cutting a cable drum to length, seal the cut ends with heat-shrink end caps. Moisture ingress into an unsealed low voltage armoured cable end will cause insulation resistance degradation within weeks in humid conditions.
8. Test before backfilling. Conduct an insulation resistance test (minimum 1 MΩ per conductor pair at 500V DC) and a continuity test on the armour before the trench is closed. Rectifying a fault after backfilling multiplies labour costs dramatically.

Common installation mistakes to avoid

Real-world inspection data from South African electrical installations reveals a consistent set of recurring errors. The most frequent is under-sized glands — installers use a gland nominally rated for 16mm cable but sized for a lighter-duty cable with a smaller overall diameter, resulting in armour wires that are not fully clamped. The second most common error is single-end earthing of the armour, which is addressed above. A third issue, surprisingly prevalent on solar installation sites, is failure to install the cable warning tape. This omission has no immediate electrical consequence but dramatically increases the risk of accidental cable strike during future groundworks — and the resulting liability is the original installer's.

Frequently asked questions

Specifying and sourcing 16mm armoured cable in South Africa requires more than matching a size to a breaker rating. SANS 1507 compliance, accurate current derating for local climate conditions, correct conductor material selection, appropriate core count and compliant installation practice are all load-bearing elements of a safe, certifiable installation. Use the tables and guidance in this article as a working reference when comparing supplier quotations, and ensure every drum you purchase carries a valid SANS 1507 test certificate for the batch supplied.