TECK90 cable explained: where it goes and how to terminate it

TECK90 comes up the moment a run leaves dry framing: a feed to a rooftop unit, a drop down a block wall to a compressor, a trench out to a detached shop. The question is rarely what TECK90 is in the abstract. It is whether the job in front of you needs it, or whether AC90 or NMD90 will do. The answer sits in the cable's construction, so start there.

What TECK90 is

TECK90 is a jacketed, armoured power cable built in layers, and each layer has a job:

• Conductors — copper in the smaller sizes, with aluminum common in larger feeder sizes, insulated with 90°C cross-linked polyethylene.
• Bond conductor — a bare bonding conductor runs with the circuit conductors, so the armour is not the only ground path.
• Inner jacket — a PVC bedding over the assembly, under the armour.
• Interlocked armour — aluminum strip wound into a flexible metal sheath. This is the mechanical protection.
• Outer jacket — a tough PVC skin over the armour. This is what separates TECK from plain armoured cable: it seals the armour against water and corrosion.

The result is a cable rated for wet locations and 90°C conductor temperature, commonly rated 600V or 1,000V, and typically marked for low-temperature installation. Versions marked for direct earth burial and for hazardous locations exist. Read the print on the jacket — the markings on the cable, not the family name, decide where it can go.

Where it is used

The method is simple: reach for TECK90 where one run needs mechanical protection and moisture protection in the same product.

• Industrial and commercial equipment feeds. Motors, compressors, rooftop units and machine feeds, run in cable tray or clipped to structure. The armour shrugs off the abuse; the jacket handles the washdowns and the weather.
• Exterior runs. Exposed along an outside wall or across a roof, TECK90 is at home where AC90 is not allowed and conduit is more labour than the run justifies.
• Direct burial. Where the cable is marked for direct earth burial, TECK90 goes in the trench without conduit. Depth of cover and protection where the cable comes up out of the ground are code matters — confirm current requirements before the trench closes.
• Outbuilding feeds. A subpanel in a detached garage or shop is the classic small-job use: one cable from the house panel, underground, no conduit run to build.

TECK90 vs AC90 vs NMD90

Three cables, three environments. Picking between them is mostly a question of where water and impact can reach the run.

• NMD90 is non-metallic sheathed cable for dry interior work — the default for residential branch circuits inside walls and ceilings. No armour, no wet rating.
• AC90 adds interlocked armour but no jackets. The armour is exposed, so it is a dry-location cable; the armour with its internal bonding strip serves as the bond path. It covers commercial interiors where cable needs mechanical protection.
• TECK90 has the armour plus both jackets plus a separate bond conductor. That combination is what buys wet locations, exposed exterior work and burial where marked.

The short version: if water can reach the run — outdoors, underground, washdown areas — NMD90 and AC90 are out, and TECK90 is the armoured answer.

Termination basics

TECK90 terminates with connectors made for it. AC90 fittings are not interchangeable — they neither fit the jacketed diameter nor seal it.

• Match the fitting to the cable. TECK connectors are sized to the cable's outside diameter, not just the trade size. Check the connector's range against the cable spec before ordering.
• Watertight where wet. Outdoor and washdown terminations need watertight TECK fittings that grip and seal the outer jacket. Hazardous locations need fittings listed for that service.
• Strip in sequence. Outer jacket back to the fitting, armour cut cleanly without nicking the inner jacket, inner jacket removed inside the enclosure. The connector clamps the armour and grounds it through the fitting body.
• Land the bond conductor. The bare bond conductor terminates on the bonding means in the box or panel. It is part of the cable for a reason — use it.
• Respect the bend radius. Armoured cable wants sweeping bends. Kinking the armour at a connector is the most common self-inflicted failure.

What to order

TECK90 is specified by conductor count and size — "3C #6 copper TECK90" is three insulated #6 conductors plus the bond. Measure the run, add slack for terminations and a drip loop at exterior entries, and round up: splicing armoured cable mid-run is worth avoiding. Browse wire and cable for TECK90 alongside the NMD90 and AC90 it replaces or complements, and pick up weatherproof boxes and covers for the exterior terminations on the same order.

Check before you install. This guide summarises common practice to help you specify parts. The Ontario Building Code, the Ontario Fire Code and the Canadian Electrical Code are the authority, they are revised periodically, and your local authority having jurisdiction can be stricter. Confirm current requirements and have the work done by a licensed electrician.