Instrumentation - hdbk10920194

DOE-HDBK-1092-98

Subassemblies, circuits, and related equipment should be segregated to the extent possible to

minimize the possibility of a fault in one device damaging another.

9.12.3 INSTRUMENTATION

Power electronics systems can involve fast pulses, high frequencies and high currents and it is

common for the voltage difference between ground in one circuit and ground in another circuit to

differ substantially. This difference can be hundreds or thousands of volts. Wire and cable shall be

insulated to withstand these potentials. Surge arrester and capacitor protection may be used to control

these potentials. DC circuits connected to coils, solenoid valves and other inductive components

should be tested for induced voltages and appropriate protection for circuits should be provided.

9.12.4 GENERAL

Test points needed for adjustment and diagnosis should be installed on the front panel or other

appropriate location of power electronic systems to facilitate their use without exposure hazard to

employees in the area.

Currents generated only during fault conditions or those introducing noise or data errors shall not be

considered objectionable currents. Bonding and grounding connections shall not be altered to reduce

the significance.

Conductors, busbars, and internal wiring should be insulated in the event objects are dropped into

the equipment.

Automatic discharge devices are not a substitute for grounding devices used for personnel protection.

Grounding points shall be located in the system and physically arranged to permit the attachment of

adequate grounding devices for the protection of personnel working on the system.

These grounding points shall be capable of carrying the short-circuit current to which they may be

subjected and applied using methods appropriate for the voltages or currents involved.

9.13 NON-IONIZING RADIATION

9.13.1 ELECTROMAGNETIC RADIATION

Human exposure to electromagnetic (EM) radiation at certain power-density levels can be hazardous.

The hazards are generally regarded to be associated with the heating of biological tissue, which

occurs when EM radiation is absorbed by a body. This heating is essentially similar to the cooking

process in a microwave oven. Use caution where EM sources are being used with the shielding altered

or removed.

When working with EM radiation, it is recommended that the emitted radiation levels be estimated

by equations and measured by radiation hazard monitors.

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