ST Suspension Numbering System

The Suspension Type (ST) numbering system is the first new insulator classification system in the hobby since Elton Gish's M numbering system for multipart porcelain insulators. It was designed by Shaun Kotlarsky and Steve Coffman to be the first system to be all inclusive of glass and porcelain insulators, as well as insulators from all over the world without distinction in the numbering range.  What this means, is that insulators are not segregated by country of origin. Glass suspension insulators are segregated into their own number range for rapid reference, but you'll find classic Pyrex right alongside modern Italian glass.  The goal was to create a more perfect system, and one readily accessible by anyone in the hobby. 

That is one reason it was decided to first post all assigned numbers online with a photograph or catalog illustration of each assigned example, and to license it under a Creative Commons license that permits any sort of non derivative use of the system for personal or commercial means. This means, a person if they so chose, could create and sell their book using the ST system without further permission, provided they properly attribute the creators and do not modify the system itself.  This level of open access will benefit the hobby by creating a sense of free community access to the core part of the work. 

The ST system is rather straightforward and simple. A thousand number block was assigned to each different type of suspension insulator, which was then further broken down into blocks for size ranges. Insulators are numbered from smallest, to largest diameter, least to most number of skirts or petticoats, then length of any extended skirts.  Numbers are not based on how the discs are connected to each other, nor by minor variants such as max weight that a unit can support. That is simply noted by the collector with each disc, much as a glass insulator collector would note a smooth base or round drip points or such. 

With the exception of a couple specialty styles, glass suspension insulators have their own number block for rapid reference by collectors who are just interested in glass insulators. We believe this enhances use of the system for the general collector, as well as specialist. 

The genesis of the ST system was born when Steve was given an 11 1/8” Jeffrey Dewitt suspension disc (ST 6800) and was frustrated by having to go to lengths to explain just what he had added to the collection. A quick message to Shaun on Facebook asking “Do you want to make a classification system for suspension insulators?” lead to the creation of the ST system we have just presented.  This fills a much needed hole in the hobby, and Shaun and Steve have received tremendous support and encouragement from many collectors. In fact, this is a largely crowd sourced effort, as many people are contributing images and catalog drawings to flesh out the system. Such a thing would not have been possible even twenty years ago, but the internet allows for the first time, rapid information gathering and dispersal, and they are grateful to all who have provided help, and the countless hours that have gone in to gathering historical information and digitizing it. 

So here you have it. The insulator collecting hobby now has one more type classification system, which hopefully benefits the hobby, and enhances the collecting experience for everyone, and furthers the sense of openness and community we all enjoy. Visit allinsulators.com regularly for official updates to the ST system!

Return to the insulator identification page