# Sonoma County Supplier Systems #SC001-0000002207

Sonoma County procurement for one 500 kVA pad-mounted transformer

**Posted:** October 22, 2026
**Respond By:** November 06, 2026
**Identifier:** SC001-0000002207
**NAICS:** 335311

Sonoma County is seeking one custom 500 kVA pad-mounted transformer for its Youth Crisis Center project in Santa Rosa.
- **Government buyer:** County of Sonoma, Purchasing Division / SPI Purchasing; named contact: Soms Suvanaseng.
- **OEMs and vendors:** No manufacturer, OEM, or commercial vendor is specified. Bidders must identify the proposed manufacturer, make, model, and catalog number.
- **Requested equipment:** One factory-assembled and factory-tested, three-phase, 60 Hz outdoor pad-mounted transformer; no part number is specified.
  - 12,470 V delta primary and 480Y/277 V secondary; copper windings; less-flammable seed-oil insulating fluid.
  - Dead-front loop-feed configuration; six 15 kV-class, 600 A primary bushings; provision for six 15 kV distribution-class MOV arresters; four-position 600 A T-blade under-oil switch; no internal fusing.
  - 95 kV primary BIL, 30 kV secondary BIL, 5.75% impedance with ±7.5% tolerance, 65°C temperature rise, and 120°C insulation class; two 2.5% full-capacity taps above and below nominal.
  - At least 99.35% efficiency at 50% load, sound level no greater than 56 dB, and suitability for operation up to 3,300 feet altitude.
- **Requirements and delivery:** Meet applicable IEEE C57, UL, and federal energy-efficiency requirements. Include specified gauges, valves, pressure-relief components, accessories, outdoor finish, factory tests and certified report, warranty information, manuals, drawings, and certified dimensions, weight, and center of gravity. Price must include packing, freight, transportation, and insurance; delivery is FOB destination. Installation and field construction are excluded. Bidders may offer their best available lead time; alternates are not accepted.
- **Shipment support:** Coordinate shipment with the County and installing contractor, provide lead-time and shipment details, and protect the equipment in transit through delivery and acceptance.
- **Award considerations:** Award is based on the lowest responsive and responsible bid meeting or exceeding specifications. Sonoma County local-business preference applies.

### Description

The County of Sonoma is soliciting bids to furnish and deliver one new 500 kVA, three-phase outdoor pad-mounted transformer for the Youth Crisis Center at Los Guilicos in Santa Rosa, California. This is an equipment-only procurement; installation and field construction are excluded. The transformer must meet the specified electrical, performance, accessory, and standards requirements, and bids must include technical documentation, factory testing information, warranty details, delivery schedule, and total delivered price. Award will be made to the lowest responsive and responsible bid meeting or exceeding the specifications.

[View original listing](https://esupplier.sonomacounty.ca.gov/psp/FN92PRD/SUPPLIER/ERP/c/SCP_PUBLIC_MENU_FL.SCP_PUB_BID_CMP_FL.GBL)