Ref620 Technical Manual Apr 2026

If you have worked on feeder protection in a distribution network, you have likely encountered the REF620. As part of ABB’s (now Hitachi Energy) Relion product family, this Intelligent Electronic Device (IED) is a workhorse for overcurrent and arc flash protection.

But let’s be honest: Opening the REF620 Technical Manual for the first time can be intimidating. At nearly 1,000 pages, it is dense. However, once you understand its structure, it becomes the most powerful tool in your toolbox. ref620 technical manual

Treat it like a dictionary—look up what you need, apply it, and move on. If you have worked on feeder protection in

Demystifying the REF620 Technical Manual: A Guide for Protection Engineers Published: April 18, 2026 it is dense. However