Installation guide

Safety

890USE17100 September 2003

Power Isolation Requirements on the Island Bus

Isolation

Requirements

The power source for the NIM, and any BOS modules on the extension segments,

must be galvanically isolated. Isolation is not provided by the NIM or BOS modules

themselves.

External Power

Supply

Requirement

Any external 24 VDC power supply that provides the source power to the island bus

must be SELV-rated. The input side must be galvanically isolated from the output

side.

This SELV requirement applies to all 24 VDC power supplies supporting both logic

power and field power—i.e., supplies that provide 24 VDC to the NIM or to an

STB PDT 3100 power distribution module.

CAUTION

IMPROPER GALVANIC ISOLATION

The power components are not galvanically isolated. They are intended

for use only in systems designed to provide SELV isolation between the

supply inputs or outputs and the load devices or system power bus. You

must use SELV-rated supplies to provide 24 VDC source power to the

island

Failure to follow this precaution can result in injury or equipment

damage.