Westinghouse Transformer Serial Number Lookup & Decoder Guide

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Written by Tan, Electrical Engineer @ Transformer4U | Last Updated: January 2026 | Reading Time: ~5 minutes

This guide explains how to decode Westinghouse transformer serial numbers to determine manufacturing
date, year, and equipment specifications.

⚑ Quick Answer: Westinghouse Serial Number Format

Format: YY-xxxxx

Year Position: Characters 1-2

Example: 7843512 β†’ 1978

1. Westinghouse Serial Number Format

Westinghouse uses the following serial number format for transformers:

Athens/Jefferson Format

Pattern: YY-xxxxx

ElementPositionMeaning
Year CodePosition 1-2Manufacturing year (2 digits or letter code)
Month/Week CodePosition nanManufacturing month or week
Sequential NumberRemaining digitsUnique unit identifier

Notes: First 2 digits = Year. Records now with ABB. Pre-1979 may contain PCBs

2. How to Decode Your Westinghouse Serial Number

πŸ“‹ Step-by-Step Decoding

  1. Locate the Nameplate
    • Padmount: Inside cabinet door
    • Substation: Tank exterior near control cabinet
    • Dry-type: Enclosure frame
  2. Find the Serial Number – Look for “S/N”, “Serial No.”, or “Serial Number” field
  3. Identify Year Code – Characters at position 1-2
  4. Decode Manufacturing Date – Use the format table above
  5. Contact Westinghouse if Needed – https://new.abb.com/

πŸ“ Decoding Example

Serial Number: 7843512

Manufacturing Date: 1978

Professional technical diagram showing Westinghouse transformer serial number format 7843512 with annotation
Figure: Westinghouse YY-xxxxx format – Year 1978 (Note: Pre-1979 units may contain PCBs)

3. Source Reliability

Source Type: πŸ“š Historical Records

Historical format. Records may now be held by successor companies.

4. Why Serial Numbers Matter

Use CaseWhy Serial Number is Critical
Warranty ClaimsWestinghouse needs serial number to verify purchase date and coverage
Replacement PartsSerial number links to specific winding configuration and tap settings
Age AssessmentDetermines remaining life expectancy (transformer life: 25-40 years)
PCB TestingPre-1979 transformers may contain PCBs requiring special handling (EPA regulations)

5. Frequently Asked Questions

❓ How do I decode a Westinghouse transformer serial number?

Locate the serial number on the nameplate, then use the format guide on this page to identify the manufacturing
date. The year is typically at position 1-2. If the format doesn’t match, contact Westinghouse directly.

❓ Where is the serial number on a Westinghouse transformer?

The serial number is located on the nameplateβ€”typically a metal or durable plastic plate
affixed to the transformer. On padmount units, it’s inside the cabinet door. On dry-type units, check the
enclosure frame.

❓ Can Westinghouse provide manufacturing date from serial number?

Yes, Westinghouse maintains production records for decades. Contact their customer support at https://new.abb.com/ with the complete serial
number to obtain the exact manufacturing date and specifications.

6. Related Resources

πŸ“ About This Guide

This Westinghouse serial number decoding guide is authored by Tan, Electrical Engineer at Transformer4U.

Serial number formats may vary by product line or manufacturing era. For authoritative
decoding, contact Westinghouse directly at https://new.abb.com/.

Disclaimer: Serial number formats may vary by product
line, manufacturing plant, and era. This guide provides general decoding information. For authoritative
manufacturing dates, contact Westinghouse directly.

Last Updated: January 2026 | Β© 2026 Transformer4U. All rights reserved.

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