1. 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; whereas for 75kVA and 150kVA it is acceptable to have fixed trip units

2. Circuit breaker Ampere Frame (AF) shall be same as Ampere Trip (AT) as per 16-SAMSS-516 paragraph 4 commentary notes.

3. Ensure that the Protection Scheme shall be in compliance with construction specifications and applicable SEC & SAES standards.  

3. Concurrence shall be obtained from project 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. 