MB and FD Series Unitized Distribution Substation Installation/Operation Guide . VTI, Incorporated 24 McMillan Way Newark, DE 19713 Phone (302) 738-0500 FAX (302) 738-6594 Manual No. 90002970 Revision Level 3.
To insure proper installation, this manual must be read prior to starting the installation process. 1. Introduction This manual covers installation instructions for the MB Series and FD Series of Unitized Distribution substations (UDS). The MB Series UDSs are implemented with a circuit breaker on the secondary of the transformer and an optional circuit breaker on the primary of the transformer.
. 3.1 CABINET WIRING Load WIRING Ensure that each load wire pair from the field is electrically disconnected from all power sources prior to handling. Pull the wire pair from each load to the UDS cabinet and route through the field wiring entry in the top of the cabinet to the circuit breaker compartment. Cut and strip the wire pair for termination on the appropriate circuit breaker and the neutral bus located at the bottom of the circuit breaker compartment.
The minimum size wire is listed in the table below: Cable Size 400/415V transformer rating Minimum wire size AWG 30 KVA 8 AWG 45 KVA 6 AWG 75 KVA 2 AWG 480v transformer rating Minimum wire size AWG 30 KVA 8 AWG 45 KVA 6 AWG 75 KVA 2 AWG Verify the feeder insulation by Hy-potting each feeder between phase and ground with voltage set to (2 x rated voltage + 1000V), e.g., 2000 VAC for 400/415 & 480V rating, and 2500 VAC for 600V rating.
Verify that the total load connected to the UDS does not exceed the rating of the transformer supplied, i.e., 30 KVA, 45 KVA or 75 KVA. Cable Size 600V transformer rating Minimum wire size AWG 30 KVA 10 AWG 45 KVA 6 AWG 75 KVA 2 AWG If the optional primary disconnect switch is installed, terminate the feeder wiring at the primary disconnect switch. Connect the three phase conductors in the cable (black, red and blue) to the disconnect terminals identified as “L1”, “L2”, and “L3”, respectively.
480 volt transformer tap chart Line voltage Tap number 504 1 492 2 480 3 468 4 456 5 444 6 432 7 600 volt transformer tap chart Line voltage Tap number 600 1 585 2 570 3 555 4 540 5
