In response to proposed TQ-012 and further to vendor (Wescosa) email, Trip units for Package Substations rating 300kVA having 500AT/600AF shall be adjustable type as per Saudi Electricity Company (SEC) specification 37-SDMS-01 paragraph 6.8. But for 75kVA and 150kVA it is considerable to have fixed trip units based on the above same reference.
Circuit breaker Ampere Frame (AF) shall be same as Ampere Trip (AT) as per 16-SAMSS-516 paragraph 4 commentary notes. 
However concurrence shall be obtained from designer (SCEC) on both the above issues and the changes with Ampere Frame (AF) sizes shall be reflected in IFC drawings before proceeding with inspections. 
Ensure that the Protection Scheme or System for Package Substations shall be same as before in compliance to construction specifications and applicable SEC & SAES standards.
