The channel cable tray shall be designed, manufactured and marked in accordance with NEMA VE 1 – 2002. eferred to support and protect numerous small instrumentation and control cables. When equipped with a solid cover, this type of cable tray can be used t -piece. In industrial settings, electrical and instrumentation (E&I) cable trays or bridge racks play a critical role in organizing and supporting power, control, and signal cables across facilities. Unlike power cables, instrumentation cables generally transmit. Q1: What is the primary purpose of cable tray sizing and calculation? Ensure the total cable area does not exceed the maximum fill area permitted by electrical codes (e.