Mortar Cable Connection Method for Electrical Cable Trays

Mortar cable connection in cable trays involves securing cables with approved fasteners, ensuring proper grounding, and embedding or routing through mortar while maintaining bending radii and electrical continuity.

Pre-

Installation Requirements

Before starting, ensure all materials, including PVC-insulated power cables, cable trays, ladders, and fasteners, are inspected and approved for use. The installation area should be clean, accessible, and pre-inspected to confirm suitability for permanent works. Construction drawings and connection schedules must be distributed to all personnel involved in the installation.

Cable Tray Installation

Tray Type Selection: Ladder trays are preferred for airflow and easy cable entry, while perforated or solid-bottom trays support lighter loads. Mounting: Secure trays using appropriate clamps, brackets, or threaded rods. Supports should be spaced 1.

5–3 meters apart depending on tray type and load. Elevations should be set using laser levels or transit points. Alignment: Ensure trays are straight, level, and properly connected using approved fittings.

Avoid drilling structural members without approval.

Cable Laying and Securing

Pulling Method: Use rollers to prevent cable dragging and maintain minimum bending radii. Maximum pulling tension must not exceed manufacturer specifications. Fastening: Single-core and multi-core cables should be secured with approved cable fasteners or saddles.

Maximum spacing for multi-core cable cleats is typically 150 mm. Identification: Each cable should have a tag indicating its number and destination.

Mortar Embedding Considerations

When cables pass through or are embedded in mortar, ensure that: Cables are protected from mechanical damage. Bending radii are maintained to prevent stress on insulation. Cable fasteners or saddles are compatible with mortar surfaces.

Expansion or movement allowances are provided to prevent strain on connections.

Grounding and Bonding

Metallic Trays: All metallic cable trays must be grounded according to NEC Article 250. 96. The tray itself can serve as the Equipment Grounding Conductor (EGC) if it meets cross-sectional area requirements.

Bonding: Use grounding clamps to bond cables to tray sections, ensuring mechanical anchoring and electrical continuity. Avoid bare copper in aluminum trays; use insulated conductors with tin or zinc-plated connectors. Multiconductor Cables: If cables contain their own EGC, ensure proper identification and bonding.

Paralleled EG

Cs may require increased sizing per NEC Section 250-95.

Final Checks

Inspect all cable connections, fasteners, and tray alignment. Verify grounding continuity and compliance with electrical codes. Ensure documentation, labeling, and cable maps are updated for future maintenance.

By following these steps, mortar cable connections in cable trays can be safely and efficiently installed, maintaining both mechanical integrity and electrical safety.