NMWU – Building Cable (Copper Conductor)

NMWU is the cable you bury. The W and the U are the whole point: wet locations and underground, direct into a trench without conduit.

Bare annealed copper, XLPE insulation, PVC sheath, rated 300V at 60°C. A bare bonding conductor comes in every construction.

Certified to CSA C22.2 No. 48 and stocked in 14/2 and 12/2 on 75 m coils, in black. Wholesale pricing on request for contractors and distributors.

What is NMWU cable used for?

NMWU carries power underground where running conduit isn't worth it. Trench feeds to a detached garage, shed or workshop. Post lights and yard receptacles. Well and sump pump circuits. Wet basements and other damp interior spots the code treats as wet locations.

The letters spell out the rating. Non-Metallic sheathed, Wet locations, Underground.

What's the difference between NMWU and NMD90?

NMD90 can't go underground. That's it in one line.

NMD90 is the indoor cable, rated for dry or damp locations at 90°C, and it's what runs inside finished walls. NMWU is rated for wet locations and direct earth burial at 60°C. Anything buried, or in contact with the ground, has to be wet-rated. Substituting NMD90 outdoors is a failed inspection and a callback.

Can you bury NMWU directly?

Yes. Direct earth burial is permitted under the Canadian Electrical Code, Part I, with no conduit required. Burial depth, mechanical protection and warning tape are set by the code and your local inspection authority, and they change depending on what's above the trench. Check both before you dig.

What does the 60°C rating change?

Ampacity headroom. A 14 AWG conductor lands at 15A and 12 AWG at 20A, the same breakers you'd expect. The difference shows up when you derate. NMD90 starts from a 90°C column and has room to give back for high ambient temperatures or bundled runs. NMWU starts at 60°C and has none. Long runs, hot trenches and grouped cables all need checking before you commit to a gauge.

Sizes we stock

14/2 and 12/2, both on 75 m coils, black jacket, bare bond included. Bulk cut lengths and full-pallet quantities are available for contractors and distributors.

Larger gauges and 3-conductor constructions aren't in stock inventory, so ask before you specify one on a drawing.

Send us the gauge, the coil count and the job's delivery date, and we'll come back with wholesale pricing and confirm availability against your schedule.