Pathways and conduit

Pathway decisions outlive every other part of the install. Cable gets replaced. Devices get replaced. The conduit and the supports stay in the walls for the life of the building. Get this layer right at design and the next twenty years of cable refreshes are pulls, not rebuilds. Get it wrong and the second cable refresh becomes a new conduit bid.

This chapter is the longest in the document because pathway choices touch every other chapter. Read it once cover to cover. The rest of the document references the rules below instead of repeating them.

Conduit type by environment

When the rule applies

Every conduit run on the project. The conduit material is decided by where the conduit lives, not by what is in it or what is on the truck. The CEC and the OBC define what is permitted in each environment; the project specification narrows it further. The list below is the working default for institutional security work in Canada.

The spec

// CONDUIT TYPE BY APPLICATION

EMT (electrical metallic tubing): interior horizontal runs above 1200 mm AFF in finished and unfinished non-detention spaces. CSA C22.2 No. 83. Insulated-throat connectors. Rain-tight fittings on any 50 mm and smaller EMT in damp or condensation-prone locations.
RGS (rigid galvanized steel): exposed exterior, semi-exterior, all interior conduit below 1200 mm AFF in mechanical and electrical rooms, conduit feeding any service over 600 V, and every conduit run inside a detention envelope.
IMC (intermediate metallic conduit): acceptable wherever RGS is required, except inside detention envelopes (where the project specification almost always names RGS) and inside classified hazardous locations. Saves labour on long exterior runs.
Epoxy-coated RGS: corrosive-atmosphere indoor and outdoor: chemical storage, water and wastewater plants, indoor pools, kitchen back-of-house, salt-storage buildings, fleet wash bays.
LFMC (liquid-tight flexible metal conduit): final connections to motorized equipment, distribution transformers, vibrating equipment, outdoor enclosures. Minimum 450 mm and maximum 600 mm with a 180° loop where possible. CSA C22.2 No. 56.
FMC (flexible metallic conduit, “Greenfield”): across building expansion joints, with no less than 600 mm of extra curve to absorb movement. Not used inside detention. Not used on supervised loops (failure is undetectable).
Rigid PVC (Schedule 40 or 80): underground branch, in-slab branch in poured concrete, underground exterior beneath paving. CSA-approved, FT4. Separate ground conductor required (PVC is not a ground).
ENT (electrical non-metallic tubing): embedded in concrete floor slabs only, with written engineer consent. CSA C22.2 No. 227.1 and No. 85. Not used in plenum or riser spaces, not used for security signal outside specific in-slab branch circuits.

Field note

Minimum conduit size

When the rule applies

Every conduit feeding a security signal, structured cabling, or low-voltage device drop. The CEC permits 13 mm (1/2”) for general branch circuits; security and structured cabling work uses 19 mm (3/4”) as the minimum because every device drop sees at least one cable replacement during the building’s life and 1/2” does not give you the working room.

The spec

Field note

Conduit support spacing

When the rule applies

Every conduit run on the project, suspended or surface-mounted, indoor or outdoor. The CEC sets maximum spacing at 1.5 m (5 ft) for EMT and 0.9 m (3 ft) for RGS in most positions. Within 0.9 m of every junction box, conduit body, and termination the spacing is tighter, regardless of conduit type. This is the most common spacing rule that AHJ inspectors fail integrators on.

The spec

Field note

What the AHJ fails you for

Hanger types by application

When the rule applies

Every conduit run that does not surface-mount directly to a wall. The clamp on the conduit is one decision; the hanger between the clamp and the structure is another. Match the hanger to what is above the conduit.

The spec

Beam clamps on exposed structural steel: Galvanized iron beam clamp sized for the flange width and the rod size. Drop a piece of all-thread from the clamp and land on a single strap or on a length of strut for multi-conduit runs.
All-thread rod from concrete inserts or drop-in anchors: For slab-mounted hangers in interior spaces. Concrete inserts are cleaner if the slab is poured around them; drop-in anchors work after the fact. Verify pull-out rating against the loaded weight.
Trapeze hangers: Two threaded rods supporting a horizontal piece of strut. Used for runs of three or more conduits, or for a single large RGS run that needs lateral stability. Size rod and strut against the loaded weight per the manufacturer’s table.
Side-beam clamps and angle brackets: For attaching conduit to wall studs, columns, and the sides of structural beams. Angle brackets give the standoff needed for a smooth bend at a corner.
J-hooks and bridle rings: For non-conduit cable support. Covered in the J-hook section below.

Field note

Conduit fittings, terminations, and bushings

When the rule applies

Every fitting between two pieces of conduit, every fitting between conduit and box, every termination. Fittings get the same care as the conduit they connect, because the fitting is where conductors are most likely to get damaged during pulling and most likely to suffer from moisture intrusion during service.

The spec

// CONDUIT FITTINGS

EMT fittings: insulated-throat steel set-screw or compression couplers and connectors
EMT in damp, semi-exterior, or condensation-prone locations: rain-tight fittings on every 50 mm and smaller
EMT compression connectors required for all conduit penetrating exterior walls, floor slabs, and any vapour-barrier penetration
RGS fittings: threaded couplings, elbows, unions. Running threads not permitted (use a coupling and a length of nipple) Galvanized to match conduit.
Conduit bodies (LB, T, C, X) for direction changes that are not full-radius elbows. Covers gasketted in damp and exterior locations.
Plastic insulating bushings on every conduit termination at every box, no exceptions
Bonding bushings on RGS runs over 600 V or where the panel schedule calls for it
Conduit waterfalls on all 4” trade-size conduit terminating in cabinets, racks, or pull boxes (cable bend protection at exit)
Sealing fittings at every classified hazardous location boundary, every interior-to-exterior wall penetration on conditioned-to-unconditioned space, and every vapour-barrier penetration. Poured with the listed sealing compound.

LBs are prohibited on communications pathways

Field note

Bend radius and bend count per run

When the rule applies

Every conduit run between pull points. Every bend is a friction point during cable pulling and a long-term stress point on the cable inside. The rules below come from the institutional communications specification and hold for every security pathway.

The spec

The two-90 rule in practice

Pull box sizing

When the rule applies

Every pull box on every conduit run. Pull boxes that are too small are the second most-common cable-pull defect after exceeded bend count. The box size is dictated by the largest conduit entering it and by the geometry of the cable making the turn.

The spec

// PULL BOX MINIMUM DIMENSIONS

Straight pull-through: minimum length equal to 8× the inside diameter of the largest entering conduit
Angle and U pulls: minimum distance from conduit entry to opposite wall equal to 6× the inside diameter of the largest entering conduit, plus the sum of the diameters of every other conduit entering on the same wall
4” trade-size conduit pull boxes: minimum 30” × 24” × 6” (762 × 610 × 152 mm) regardless of the 8× calculation result
Vertical conduits: pull boxes provide straight pass-through for vertical cables (no off-axis turn at the box)
Pull box covers: screw-type, not hinged
24” × 24” minimum access panel where pull boxes are installed in inaccessible ceiling spaces
Pull boxes provided at every 30 m (100 ft) of run, at not less than 30 m intervals
Cover labelled with the system designation (security signal, communications, power) and circuit identification per chapter 06

Field note

Backboxes for security devices

When the rule applies

Every device on a security install lands in a backbox. The backbox dimension is the difference between a clean termination with service slack and a cable jammed against the device that fails three years in.

The spec

// BACKBOXES BY DEVICE TYPE

Communications and security signal general: 4-11/16” × 4-11/16” × 2-1/2” (119 × 119 × 64 mm) minimum
Workstation outlets, double-gang locations: double-gang box with 25 mm (1”) conduit minimum to nearest raceway or pull point
Card reader at door: single-gang or double-gang to match reader cutout, 2-1/2” minimum depth, 19 mm (3/4”) conduit to the door junction or panel
Camera at finished ceiling: 4” octagon or 4-11/16” square box, supported independently from ceiling grid, attached to structural ceiling
Camera on exterior wall: 4-11/16” weatherproof cast box (FS or FD series), gasketted cover, conduit entry from below or rear
Door position switch: 4” square box at door header, strike side, 50 mm (2”) in from frame edge
Request-to-exit (REX) sensor: above door frame, centred over clear opening
Intercom station: depth and dimension per manufacturer mounting cutout, 25 mm (1”) conduit minimum to riser
Through-wall, exterior, vapour-barrier: cast Feraloy (FS, FD) with sealed entries
Plaster ring / raised cover: 3/8” deep minimum on every stud-wall backbox to bring device flush with finished surface
Stagger backboxes in walls and partitions; no back-to-back. Seal against sound transmission per architectural acoustic spec.
Through-wall boxes: prohibited for any application

Field note

Conduit fill

When the rule applies

Every conduit on the project, sized at design and verified at pull. The CEC’s fill table is the inspection-day rule. The design-day rule is tighter, because a conduit at code maximum on day one has no room for additions or substitutions.

The spec

// CONDUIT FILL LIMITS

Design-day maximum: 30% of conduit cross-sectional area
Code-day maximum (CEC Table 8): 40% for three or more conductors, 31% for two conductors, 53% for one conductor
Cat 6A in 21 mm (3/4”) EMT: 2 cables max at code, 0 cables with design margin
Cat 6A in 27 mm (1”) EMT: 3 cables at code (137 mm² at 40%, 132 mm² actual cable)
Cat 6A in 35 mm (1-1/4”) EMT: 4 to 6 cables with design margin
Different cable types in same conduit: only where code permits (no power and signal mixing) and worst-case bend radius and pull tension are met for all types
Coax and Cat 6A: never in the same conduit. Separate conduits or metallic divider in cable tray.
20% spare conduit capacity in every underground duct bank and every backbone riser, minimum one fully-empty spare conduit per route
Use manufacturer’s actual jacket diameter from the data sheet, not the nominal value, when fill is within 5% of the limit

Worked example

Expansion and seismic fittings

When the rule applies

Every metallic conduit run that crosses a building expansion joint, plus PVC conduit on long runs that see significant temperature swings. Buildings move. Conduit that crosses an expansion joint without an expansion fitting transfers the movement to the conduit and either the conduit cracks at the fitting or the cable inside fatigues until it opens.

The spec

// EXPANSION FITTINGS

Manufactured expansion fitting at every building expansion joint crossed by metallic conduit
Movement allowance: minimum 100 mm (4”) axial travel for typical building joints, or as specified by the structural engineer for the project’s specific joint movement
FMC (galvanized steel flexible) acceptable at expansion joints with no less than 600 mm (24”) extra curve
PVC conduit: manufactured expansion fittings at the spacing recommended by the conduit manufacturer (typically every 30 m indoor, every 9 m outdoor, against calculated thermal movement)
Seismic restraints on conduit runs above 50 mm (2”) trade size in seismic Category C and higher zones; restraint design from the structural engineer
Bonding jumper around every expansion fitting on RGS to maintain ground continuity (jumper sized per CEC Table 16)

Thermal expansion math for PVC runs

Field note

Sealing fittings and vapour-barrier penetrations

When the rule applies

Every conduit penetrating from a conditioned interior space to an unconditioned exterior space. Every conduit crossing a vapour barrier on a conditioned-space wall. Every classified hazardous location boundary.

The spec

// SEALING FITTINGS

Sealing fitting at every interior-to-exterior wall penetration on conduit between conditioned and unconditioned space
Sealing fitting at every classified hazardous location boundary per CEC Section 18 and the area classification drawing
Sealing fitting at every vapour-barrier penetration, on the warm side of the vapour barrier
Fitting installed with the cover on the accessible side of the wall, vertical orientation that allows poured compound to fill the chamber without trapping air
Sealing compound: manufacturer-approved (Chico A or equivalent), poured to the level of the fitting’s pouring slope, cured per the manufacturer spec before energizing or pulling cable
Conductor count limited per fitting size table (the fitting’s heat dissipation defines a maximum conductor cross-section)
Fitting installed before cable pulling. Sealing compound poured after termination is complete on both sides.

The exterior camera condensation trap

Field note

Mounting heights for security devices

When the rule applies

Every device on the install. The heights below are field defaults; project drawings and AHJ override where the application is specific. ADA-compliant heights apply to any device a member of the public is expected to operate, including readers at public entries, intercoms at vestibules, and panic-button devices in public-access areas.

The spec

// MOUNTING HEIGHTS (AFF UNLESS NOTED)

Card reader, general: 1100 mm (44”) to centre of reader, ADA-compliant; 1200 mm (48”) where ADA does not apply
Card reader, door-operator paired: 1000 mm (40”) to centre, coordinated with the operator push plate height
Door position switch: top of door frame, strike side, 50 mm (2”) in from frame edge
Request-to-exit (REX) sensor: above door frame, centred over clear opening
Intercom station, general: 1200 mm (48”) to centre of speaker grille
Intercom station, ADA vestibule: 1100 mm (44”) to centre, call button reachable per ADA
Camera, interior general: 2700 mm (108”, 9 ft) AFF minimum, structural ceiling or wall
Camera, exterior perimeter: 4000 mm (157”, 13 ft) AFF minimum, on building exterior or pole, vandal-resistance considered for public elevations
Camera, detention holding cell: 3700 mm (12 ft) AFF minimum, anti-ligature hardware, fed from secure side (chapter 16)
Glassbreak detector: 4500 mm (15 ft) maximum distance from protected glass, opposite or adjacent wall at ceiling level
Motion detector (PIR, dual-tech): 2200 to 2700 mm (88-108”) AFF, aimed across the room rather than down
Panic button under desk: no specific AFF, mounted at natural seated reach
Wall-mounted control panel and keypad: 1200 mm (48”) to centre, general staff; 1100 mm (44”) for ADA-required locations
Surface-mounted backbox depth: 19 mm (3/4”) protrusion minimum from finished wall
Through-wall conduit protrusion into rooms: 75 mm (3”) minimum
Floor sleeves: 50 mm (2”) minimum above finished floor

Surface raceway

When the rule applies

Retrofit work where the wall cannot be opened. Exposed runs in finished public spaces where architecture prefers a clean rectangular profile over visible round conduit. New-build situations where in-wall conduit was not specified at design and adding it after framing is impractical.

The spec

// SURFACE RACEWAY

Steel surface raceway, two-piece (base and cover), powder-coated finish matching architectural specification
Raceway sized so calculated cable cross-section is no more than 40% of raceway internal area at install
Profile by application::
- 700 series. short runs of one or two communications cables
- 2000 series. typical multi-cable run
- 4000 series. high-density risers and patch panel feeds
- 6000 series. backbone feeds where multiple raceways converge
Boxes, fittings, accessories from the same series and same manufacturer as the raceway
Internal fittings factory-formed; no field-formed transitions except at custom junction boxes designed for the application
Fastener spacing: 1.0 m (3 ft) maximum on raceway base, fastener within 150 mm (6”) of every box, fitting, and termination
Bonding: each section grounded to the equipment ground in the served device or to the building TGB per chapter 04

Field note

Cable tray

When the rule applies

High-density runs in equipment rooms, riser shafts, and any space where the cable count exceeds what conduit can practically support. Wire-mesh tray is the institutional standard for communications work. Ladder and solid-bottom trays serve other applications and are out of scope here.

The spec

// WIRE-MESH CABLE TRAY

Wire-mesh, 5 mm (0.196”) wire diameter minimum, welded intersections forming 50.8 × 101.6 mm (2” × 4”) grid
Sections 3048 mm (10 ft) or 1524 mm (5 ft)
Widths 100 mm (4”) through 610 mm (24”) sized to calculated cable count plus 25% spare
Sidewall heights 50, 102, or 152 mm sized so cable fill never exceeds side rail height
Tray ends formed downward at 90° for drop-in installation onto manufacturer supports
Hot-dipped galvanized after fabrication. UL Classified for grounding purposes.
All system components from a single manufacturer
Cable fill: cable cross-sectional area no more than 50% of interior tray area. Cable depth never exceeds the side-rail height.
Tray support spacing: 1.5 m (5 ft) maximum per ANSI/EIA/TIA-569-C; supports within 0.6 m (2 ft) of every splice or intersection if not directly under the splice
Support on both sides of every elevation change
Clearance: 305 mm (12”) above and below tray, 305 mm between stacked trays, 76 mm (3”) above drop-ceiling tiles, 25 mm (1”) between top of tray and bottom of raised-floor tile
Different media types in same tray: full-length metallic divider, each media calculated independently against 50% of its divided area
Bonded to TGB with #6 AWG bonding conductor, bonds verified at every splice and intersection (chapter 04)

Field note

J-hooks for non-conduit cable support

When the rule applies

Low-density horizontal cable runs in accessible ceiling spaces above finished rooms, where conduit is overkill and tray would be wasteful. J-hook support is acceptable only where the engineer of record has signed off on the application.

The spec

// J-HOOK CABLE SUPPORT

NRTL-listed J-hook for plenum installation where the ceiling is a plenum return
Telecommunications-specific J-hook with bearing surface wide enough to honour the bend radius of Cat 6A and high-performance fiber
Flared edges to prevent damage during cable installation
Top latch or removable retainer strap to hold the bundle; retainer removable and reusable in plenum applications
Spacing: 1.5 m (60”) maximum on horizontal runs not in conduit or tray
Fill: 25% maximum of hook’s stated capacity at install, leaving 75% for future cable additions
Cable slack between hooks: 150 mm (6”) minimum above ceiling, measured from lowest point of cable to top of ceiling tile or structure
J-hook at every change in direction (in addition to the run-spacing rule)
Supported from structural ceiling (deck above), not from suspended ceiling grid wires
Cables not supported by ductwork, piping, or ceiling-grid wires

Field note

Riser slots, sleeves, and floor penetrations

When the rule applies

Vertical conduit and cable runs between floors. These penetrations are firestopped at every floor per chapter 05, but the slot or sleeve geometry is decided at the pathway-design stage and the firestop comes after.

The spec

// FLOOR PENETRATIONS

Slot or sleeve protrudes minimum 50 mm (2”) above finished floor at the upper level (curb to keep water from entering the riser)
Sleeve material matches riser conduit material: galvanized steel for steel conduit, Schedule 40 PVC for PVC conduit
Sleeves sized 25% larger than the conduit OD to accept the firestop product without compromising the conduit fit
Slots in floor slabs sized for as-built cable count plus 25% spare, with firestop product compatible with slot geometry
Conduit terminates with plastic bushing on both sides of the floor penetration. Bushing independent of firestop, stays in place after firestop is applied.
Multi-cable slot fed by tray or J-hook: tray or hook continues into and through the slot, supported on both sides of the floor
Slots and sleeves identified on as-built drawings with type, fire rating, and firestop product reference per chapter 05
Floor and wall slots and sleeves firestopped after cable installation per chapter 05. The slot or sleeve itself is not a firestop.

Separation from power and other systems

When the rule applies

Every communications and security signal pathway. The numbers below apply to open cable, J-hook, conduit, and cable tray pathways. The CEC and the institutional communications spec both reference these distances.

The spec

// MINIMUM SEPARATION DISTANCES

Unshielded power lines or electrical equipment, open or non-metallic pathway:
- <2 kVA: 127 mm (5”)
- 2 to 5 kVA: 305 mm (12”)
- >5 kVA: 610 mm (24”)
Unshielded power, grounded metal conduit pathway:
- <2 kVA: 64 mm (2.5”)
- 2 to 5 kVA: 152 mm (6”)
- >5 kVA: 305 mm (12”)
Power lines in grounded metal conduit, grounded metal conduit pathway:
- 2 to 5 kVA: 76 mm (3”)
- >5 kVA: 152 mm (6”)
Motors and transformers: 1.2 m (4 ft) minimum on every side
Power conduit and cables <1 kV: 0.3 m (1 ft) minimum
Power conduit and cables >1 kV: 1.0 m (3 ft) minimum
Fluorescent and similar luminaires: 300 mm (12”) minimum
Pipes (gas, oil, water, hydronic): 120 mm (5”) minimum
HVAC equipment, ducts, and fittings: 150 mm (6”) minimum
Coax (CCTV/CATV) and Cat 6A: never in the same pathway. Separate conduits or metallic divider in cable tray.

Why 150 mm from hot pipes

Identification and labelling on conduit

When the rule applies

Every conduit on every project. Identification at both ends with destination, system designation, and project-standard colour band. Detail in chapter 06.

The spec

Underground and direct-burial pathway

When the rule applies

Conduit between buildings, between equipment yards, between the building and the perimeter. The institutional default is a concrete-encased duct bank for any campus run.

The spec

// UNDERGROUND PATHWAY

Concrete-encased duct bank: PVC conduit (Schedule 40 minimum, Schedule 80 in high-load areas) embedded in red-dyed concrete
20% spare conduits in every duct bank, minimum one fully-empty spare. A 4-conduit bank is built with 5 conduits.
Slope: 1% minimum toward a drainage point (handhole, manhole, or building entry pit)
Drainage point: handhole or manhole at the low point with a sump sized to absorb expected groundwater inflow
Direct-burial flexible polyethylene only where duct bank is not permitted; depth and warning tape per CEC and provincial dig-safety
Conduit bed: well-tamped flat earth, free from rocks. Sand backfill around the conduit to project-spec depth.
Pull cord: 3 mm minimum polypropylene fish line in every conduit, occupied and spare
Underground-to-building entry: PVC or RGS sweep elbow to a conduit body, then to interior pathway. Sealing fitting on the interior side of the building wall.
Manhole or handhole: pre-cast concrete, lid sized to conduit count, ground rod inside connected to building TGB through the duct-bank bonding conductor
OSP-to-indoor transition splice: inside a manhole, handhole, or interior pull box within 15 m of the boundary (chapter 07)

Field note

The detention envelope: where the pathway changes

When the rule applies

Inside detention areas, holding cells, sallyports, and the prisoner-side of any custody door. The pathway rules tighten substantially. Detail in chapter 16; this section captures the pathway-side rules so the detention chapter does not repeat them.

The spec

// PATHWAY IN DETENTION ENVELOPE

RGS only. EMT, IMC, FMC, LFMC, and PVC are not used inside the detention envelope.
Conduit feeds device boxes from above through the slab where structure permits, with the device box at 3.7 m (12 ft) AFF or higher
Tamper-resistant fastener heads on every conduit support, every box cover, every device cover (Torx with security pin, Tri-wing, or one-way as the project specification calls for)
Conduit body covers (LB, T, C, X) prohibited inside the protected space. Junction and pull boxes only with screw-cover and screws inaccessible from the protected side.
Caulk and sealant at every conduit penetration: pick-resistant detention-grade sealant per chapter 16. Standard fire-rated caulk is not pick-resistant.
Cable serviced from the secure side of the wall. Every device on the prisoner-facing wall fed by conduit running through the secure-side mechanical chase. Box opening and service access on the secure side only.
No ceiling-cable or J-hook runs inside the protected space. All cable in conduit, all conduit terminations on the secure side.
Anti-ligature considerations: no grab points, no exposed conduit below 3.7 m, double-strap every support, and pick-proof every visible fastener