What Are AC 90 BX Cable?

AC 90 BX cable is an armoured electrical cable assembly with insulated conductors inside a flexible interlocked metal armour. In trade language, many buyers still say BX cable, although product naming and code language should be checked carefully because different armoured cable constructions are not always interchangeable. AC 90 is generally chosen when a project needs a wiring method with mechanical protection, a familiar installation process, and less field labour than a full conduit system in suitable applications. Depending on the exact product, it may be used for power distribution, branch circuits, and some equipment feeds in dry or otherwise approved locations.

Where Are AC 90 BX Cable Used?

AC 90 BX cable is commonly used in commercial tenant fit-outs, schools, offices, apartment corridors, utility rooms, suspended ceiling spaces, and renovation work where routing conduit would add time or cost. It is also used in some industrial and institutional interiors where the environment is not excessively corrosive or otherwise outside the cable listing. Electricians often choose it for exposed runs above accessible ceilings, in wall cavities, and in service areas where the armour helps protect the conductors from incidental contact. It is less suitable where washdown, direct burial, continuous outdoor exposure, or severe corrosion resistance is required unless the exact cable construction is specifically approved for those conditions.

How To Choose AC 90 BX Cable

Start with the circuit type and load. Confirm conductor size, number of conductors, grounding or bonding arrangement, and voltage rating based on the equipment being served. Then look at the installation environment: dry indoor spaces, concealed runs, exposed service spaces, and retrofit pathways all affect whether AC 90 is a practical fit. Copper conductors are often preferred for easier terminations and smaller sizes, while aluminium may be considered on larger feeders where weight and cost matter, provided all lugs and devices are rated for aluminium. Also check outside diameter, minimum bend radius guidance, connector compatibility, and whether the armour and bonding design match the intended system grounding method. For larger cable sizes, labour savings from lighter conduit work can be offset by more difficult handling and support, so installation practicality should be reviewed before ordering.

Trade Rules Of Thumb

As a typical rule of thumb, AC 90 becomes more attractive when you want faster rough-in than conduit but more protection than non-metallic cable. It is often a good fit for indoor branch circuits and moderate feeder runs in commercial spaces with repeated layouts. Another practical rule is that cable handling gets noticeably harder as conductor count and size increase, so what works well for smaller branch circuits may become less efficient on larger feeders with multiple bends. For retrofit work, armoured cable can reduce disruption where existing finishes limit conduit routing options. These are practical buying and installation observations only, not code rules, and final suitability depends on the exact cable listing, support method, and local code interpretation.

Sizing Guidelines

Cable sizing should be based on calculated load, overcurrent protection, conductor temperature rating, termination limits, ambient conditions, and voltage drop. As a practical rule of thumb, branch circuits with longer runs may need upsizing even when base ampacity appears adequate, especially where lighting or motor loads are sensitive to voltage drop. For feeders, buyers should also consider future capacity, fault current, and available termination space in panels and equipment. If aluminium conductors are being considered, verify connector ratings, oxide inhibitor practices where required, and any size adjustments needed for equivalent ampacity. Always use the Canadian Electrical Code, equipment nameplates, and manufacturer data for final sizing and derating decisions.

Common Installation Practices

Common practice is to plan AC 90 runs to minimise unnecessary bends, protect the cable from sharp edges, and use listed connectors matched to the cable type and trade size. Installers typically support the cable neatly, maintain consistent routing, and leave enough slack for clean terminations without over-bending the armour. Armour cutting tools are often used to avoid nicking conductor insulation during preparation. In panelboards, junction boxes, and device boxes, adequate box fill and bending space should be checked early because armoured cable can crowd enclosures faster than expected. Bonding continuity, connector tightness, and conductor identification should be verified before energising. Exact support intervals, bonding requirements, and installation details must follow code and product instructions.

Common Mistakes

One common mistake is treating all BX or armoured cable as interchangeable when the exact construction and approval may differ. Another is choosing AC 90 based only on ampacity without considering outside diameter, bend difficulty, connector size, or enclosure space. Installers also run into trouble when they damage insulation while stripping armour, fail to use the correct fittings, or assume the bonding path is acceptable without checking the cable design and local requirements. On larger jobs, underestimating cable weight and pull effort can slow installation and increase rework. Buyers should also avoid using AC 90 in wet, corrosive, or exposed conditions unless the specific product is listed for that environment.

Brand Comparisons

Brand selection in AC 90 BX cable is often less about headline marketing and more about availability, conductor consistency, armour handling, print legibility, and how familiar the crew is with the product. On many projects, matching an existing approved cable brand may simplify submittals, inspection, and maintenance. Where multiple acceptable brands are available, electricians often compare reel handling, strip quality, connector fit, and lead times rather than assuming one brand is universally better. If you are replacing or extending an existing installation, matching conductor material, cable type, and fitting system is usually more important than switching brands for a small price difference. Because no specific brands are provided here, the practical approach is to compare listed approvals, construction details, and jobsite handling characteristics before purchase.

Related Products

Buyers shopping AC 90 BX cable often also need armoured cable connectors, anti-short bushings where required by product instructions or local practice, junction boxes, device boxes, straps and supports, panelboard terminations, grounding and bonding accessories, and cable cutting or armour stripping tools. Depending on the project, related wiring methods may include TECK cable, conduit and fittings, tray cable, or Loomex and NMD90 for concealed dry residential work where permitted. It is also common to compare copper and aluminium lugs, mechanical connectors, and enclosure accessories at the same time so the cable selected can be terminated without field substitutions.

Frequently Asked Questions

Is AC 90 the same as BX cable?

In everyday trade language, many people use BX as a general term for armoured cable, but the exact cable type matters. AC 90 is a specific armoured cable designation, and it should not be assumed to be identical to every product someone informally calls BX. Always verify the actual cable marking and approval.

Where is AC 90 commonly used in Canada?

It is commonly used in indoor commercial, institutional, and multi-residential construction for branch circuits and some feeder applications where mechanical protection and faster installation than conduit are both important. Final use depends on the exact cable listing and local code acceptance.

Can AC 90 be used instead of Loomex or NMD90?

Sometimes, yes, but they are different wiring methods intended for different installation conditions. AC 90 is typically chosen when more physical protection is needed or when the project specification calls for armoured cable. Loomex or NMD90 may still be more practical in permitted concealed dry residential applications.

What should I check before ordering AC 90 BX cable?

Check conductor size, number of conductors, copper or aluminium construction, voltage rating, cable diameter, connector compatibility, environment rating, and whether the cable suits the project specification. It is also smart to confirm reel length, handling weight, and enclosure space requirements before purchase.

Does AC 90 save labour compared with conduit?

Often it does on suitable indoor runs because it can reduce the number of separate raceway components and field bending steps. However, on larger cable sizes or more complex routes, handling difficulty, support work, and termination time can reduce that advantage.

Can AC 90 be used outdoors or in wet locations?

Not by assumption. Some armoured cable products are intended mainly for dry indoor use, while others may have different approvals. Always check the exact product listing, manufacturer instructions, and code requirements before using any armoured cable in wet, outdoor, or corrosive environments.