What to Include in a Transformer RFQ / Specification

Published 27 Aug 2026Updated 27 Aug 20266 min readIntermediateProcurement
Quick answer — A transformer RFQ must give the supplier enough to quote correctly: the MVA/kVA rating, both voltage levels and tappings, frequency, impedance, vector group, cooling, insulation class, temperature rise, losses, standards, duty, and the installation environment (indoor/outdoor, altitude, ambient, contamination). Missing data leads to mismatched quotes and delays.
Contents
What information should be in a transformer RFQ?

The electrical data

Rated power, HV and LV voltage, tapping range and step, off-circuit or on-load tap-changer, frequency, %Z and tolerance, vector group, and the specified no-load and load losses.

Design and duty

Cooling class and auxiliary rating, temperature rise, insulation class, BIL/impulse level, and any special duty such as converter, furnace, traction, or reactor service.

Environment and installation

Indoor or outdoor, altitude, ambient temperature range, humidity, contamination level, seismic, noise limit, and the site layout and transport constraints.

Commercial and quality

Governing standard, required routine/type tests, delivery date, warranty, spares, site or FAT requirements, and the documents you want with the offer.

References & standards

Related

CalculatorBook seriesAcademy

Related manufacturers

Prolec GE (GE Vernova) · Prolec GE Waukesha · Hitachi Energy USA · Siemens Energy · Eaton · Virginia Transformer Corp

Related components

On-load tap changers Transformer bushings & terminations
Technical content is prepared from engineering references, standards frameworks, manufacturer documentation and industry sources. Contractual or compliance decisions should refer to current official standards. TransformerPath Technical Editorial.
Source transformers for this application

Submit an RFQ or browse manufacturers and components.

Submit an RFQ Get Verified