Tyco Electronics’ circuit protection group designs and manufactures components that help equipment manufacturers comply with published safety and performance standards. It is also actively involved in the development of telecom industry standards.

This paper is intended to help designers and manufacturers understand the new Issue 4 of GR-1089 CORE requirements and the associated protection requirements. The protection design approach will depend on whether or not the type of primary protector is known, or can be specified. After that has been determined, several other considerations must be made in order to ensure that equipment will be able to withstand the full force of the surge and power fault testing as specified in Issue 4. Another important design consideration is the system "cost of survival".