Use splice plates (couplers) on the sides to connect them. Insert the mushroom-head bolts from the inside of the tray pointing out (this protects cables from snagging on bolt threads) and tighten the nuts on the outside. This is a critical safety step. The most common cable tray connection methods include: Each method differs in installation time, cost, flexibility, and strength. Choosing the right one depends on project conditions, load. This guide covers the critical steps, from selecting the right electrical cable tray and performing accurate cable fill calculations to managing a safe cable pull through and ensuring all bonding and grounding requirements are met. For licensed electricians, mastering these principles is essential. We recognize the need for a complete cable tray reference source for electrical engineers and designers. The information has been organized for. s as grounding conductor equipment. In accordance with National Electrical Code (NEC) Article 392 “Cable trays” first determine the Maximum Fuse Ampere Rating or Circuit Breaker Ampere Trip Setting or Circuit Breaker Protective Relay Ampere Trip Setting for Ground-Fault Protection s the minimum. But before you lay the first tray or clamp down a single cable, you need a solid plan.