* Spacing between wired devices and wireway or other obstructions: 2′′ minimum; 2 1/2 – 3′′ preferred for 120VAC and less. As modern bus interface frequencies scale higher, care must be taken in the printed circuit board (PCB) layout phase of a design to ensure a robust solution. Rotation of the PCB. When applying Power Distribution Blocks (PDBs), there are various requirements that shall be satisfied, based upon different UL Standards, the NEC®, and the specific application. Some of the requirements and ratings include: voltage, continuous current, wire range (load and line side). This document is intended to be used to determine the requirements for components when used in industrial control panels. This document replaces what was Supplement SA in the Second Edition of UL 508A, and subsequently Appendix C in the Third Edition of UL 508A. Generally instrument cabling is usually run in. Modular terminal blocks for Signal marshalling for extremely compact yet clear panel design Increasingly complex requirements for automation processes and increasing demands in terms of monitoring and recording operational data have led to an ever-increasing number of sensors in the field for. This document details the requirements with regard to installing Structured Cabling Systems (SCS) in the vicinity of power circuits normally associated with Customer Premises.