What Are NMD90?

NMD90 is a non-metallic sheathed cable assembly that typically includes two or more insulated conductors plus a bonding conductor under an outer jacket. It is widely used for 300 V residential branch circuit wiring in dry locations. In practical terms, it is the standard cable many electricians reach for when wiring receptacles, lighting circuits, switches, smoke alarms, and a range of dedicated household loads in finished walls, ceilings, and floor systems. The 90 deg C conductor insulation supports modern termination and derating considerations, but allowable ampacity for a completed installation still depends on the applicable rules, terminal temperature ratings, and circuit design.

Where Are NMD90 Used?

NMD90 is most commonly used in houses, apartments, condos, secondary suites, and similar dry indoor occupancies. Typical applications include general lighting circuits, bedroom and living area receptacles, kitchen small-appliance branch circuits where the conductor size is appropriate, bathroom receptacle circuits, smoke and CO alarm wiring, and dedicated runs to equipment such as dishwashers, range hoods, furnaces, and similar loads where permitted. It is generally well suited to concealed runs through wood studs and joists. It is not the usual choice for wet locations, underground runs, exposed outdoor work, or areas where the cable may be subject to mechanical damage unless additional protection is provided and the installation method is acceptable.

How To Choose NMD90

Start with the circuit rating and the load. For many residential jobs, the first decision is whether the circuit is 15 A or 20 A, which often points buyers toward 14 AWG or 12 AWG copper respectively. Next, choose the conductor count. A 2-conductor with bonding wire cable is common for straightforward line-neutral branch circuits. A 3-conductor with bonding wire cable is often selected when an extra insulated conductor is needed for switching arrangements, interconnected devices, split wiring arrangements where permitted, or certain equipment connections. Then consider run length. On longer runs, upsizing may be worthwhile to manage voltage drop even when minimum ampacity is technically met. Also think about box fill, ease of pulling through framing, and whether the cable will be installed in a way that keeps it protected from nails, screws, and physical damage. Final selection should always be checked against the actual load, breaker size, equipment nameplate, and local code enforcement practice.

Trade Rules Of Thumb

For everyday residential work, a few practical rules of thumb help narrow the choice quickly. First, 14 AWG copper is typically paired with 15 A overcurrent protection, while 12 AWG copper is typically paired with 20 A protection. Second, if the run is long and the load is continuous or sensitive to voltage drop, many electricians consider upsizing one conductor size as a practical step even when not strictly required by minimum ampacity. Third, 2-conductor cable handles most simple branch circuits, while 3-conductor cable is worth choosing when there is any chance the extra conductor will avoid a return trip or a field splice workaround later. Fourth, for renovation work, matching the existing wiring method and conductor size can simplify troubleshooting and future service. These are practical buying rules only, not code substitutes.

Sizing Guidelines

Common NMD90 sizes in residential work include 14/2, 14/3, 12/2, and 12/3, each with a bonding conductor. As a typical guide, 14/2 is often used for 15 A lighting and receptacle circuits, 12/2 for 20 A receptacle or dedicated appliance circuits, 14/3 for 3-way switching or other circuits needing an extra insulated conductor on 15 A protection, and 12/3 for similar 20 A applications. Heavier sizes such as 10 AWG may be used for specific dedicated loads where the equipment and overcurrent protection call for it. Voltage drop is not usually the first issue on short residential runs, but it becomes more relevant on detached structures, long home runs, and higher-current loads. Conductor sizing must also account for bundling, ambient temperature, terminal ratings, and any equipment-specific instructions. Use the current code and manufacturer documentation for final sizing decisions.

Common Installation Practices

In typical wood-frame construction, NMD90 is run through bored studs and joists, stapled and supported in accordance with code, and terminated in approved device and junction boxes. Good practice includes keeping cable runs neat, protecting the cable where it passes near framing edges, avoiding jacket damage during pulling, and leaving enough free conductor length for clean terminations. Electricians also pay attention to box fill, especially when several cables enter one switch or receptacle box. In unfinished areas where the cable may be exposed to impact, additional mechanical protection may be needed or another wiring method may be more suitable. Where the cable transitions to equipment, proper connectors, strain relief, and bonding continuity matter just as much as conductor size.

Common Mistakes

One common mistake is choosing cable by habit instead of by circuit requirements, such as using 14 AWG where a 20 A circuit is intended. Another is overlooking the need for a third insulated conductor, which can create unnecessary splices or force a cable change later. Buyers also sometimes assume NMD90 can be used anywhere indoors, even in damp, exposed, or damage-prone locations where it may not be the right wiring method. On the installation side, overdriven staples, nicked insulation, poor support spacing, crowded boxes, and weak planning around long-run voltage drop can all create avoidable problems. For service work, failing to match the existing conductor size and circuit protection is another frequent source of callbacks.

Brand Comparisons

Because no specific brands are listed for this page, the most useful comparison is by cable consistency, jacket handling, conductor strip quality, print legibility, and availability of the sizes you use most often. In the Canadian market, many electricians stay with a familiar cable brand when they want predictable pulling feel, easier jacket stripping, and consistent packaging from job to job. Others will cross-shop based on price, reel format, and stock availability, especially for standard 14/2 and 12/2 house wiring. When matching an existing installed brand on a service or phased project, consistency can be helpful, but for most standard residential branch circuits, equivalent certified NMD90 from a reputable manufacturer is usually suitable if the size, conductor count, and application are correct. The better buying decision is often the cable that is in stock, properly certified, and practical for the job rather than simply the most familiar label.

Related Products

Products commonly purchased alongside NMD90 include device boxes, vapour barrier boxes, staples, cable connectors, marrettes or other approved wire connectors, receptacles, switches, AFCI and GFCI breakers where required, panelboards, bonding hardware, and rough-in accessories. Depending on the project, buyers may also need armoured cable for exposed areas, conduit and fittings for mechanical protection, low-voltage cable for controls and communications, and dedicated appliance whips or connectors for final equipment terminations. For planning purposes, it is often efficient to order cable together with boxes, fastening hardware, and protection plates so the rough-in crew is not delayed by missing small parts.

Frequently Asked Questions

Is NMD90 the same as Loomex?

In Canadian trade language, Loomex is commonly used as a general term for NMD90-style non-metallic sheathed cable, even though Loomex may also be used as a brand reference in some contexts. On most jobs, when someone asks for Loomex, they usually mean NMD90 house wire.

Can NMD90 be used outdoors?

NMD90 is generally intended for dry indoor locations. Outdoor, wet, underground, or direct-burial applications usually require a different cable or wiring method. Confirm the exact installation method before ordering.

What is the difference between 14/2 and 14/3 NMD90?

14/2 typically has two insulated conductors plus a bonding wire, while 14/3 typically has three insulated conductors plus a bonding wire. The extra insulated conductor is useful for switching arrangements and other circuits that need more than a simple line and neutral.

When should I choose 12 AWG instead of 14 AWG?

12 AWG is commonly chosen for 20 A circuits and may also be preferred on longer runs to help reduce voltage drop. The correct choice depends on breaker size, load, run length, and the applicable code and equipment instructions.

Can NMD90 be run exposed in a basement or utility area?

It depends on whether the cable is considered protected from mechanical damage and whether the installation method is acceptable in that space. In unfinished or service areas, exposed cable may need additional protection or a different wiring method.

Does NMD90 always include a bonding conductor?

For standard residential branch circuit cable assemblies, a bonding conductor is typically included. Buyers should still verify the exact cable description on the product listing to confirm conductor count and configuration.