2 general wiring practices for power wiring – Honeywell 9782 Series User Manual

Page 52

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Conductivity/Resistivity Analyzer/Controller

9782 Series Conductivity/Resistivity Analyzer/Controller - Operator’s Manual

7/99

4-2

4.2 General Wiring Practices for Power Wiring

WARNING

Wiring should be performed by qualified personnel only.

Safety precautions

WARNING

A disconnect switch must be installed to break all current carrying conductors. Turn off power
before working on conductors. Failure to observe this precaution may result in serious personal
injury.

WARNING

An external disconnect switch is required for any hazardous voltage connections to the relay outputs.

Avoid damage to components

ATTENTION

This equipment contains devices that can be damaged by electrostatic discharge (ESD). As
solid state technology advances and as solid state devices get smaller, they become
increasingly sensitive to ESD. The damage incurred may not cause the device to fail
completely, but may cause early failure. Therefore, it is imperative that assemblies containing
static sensitive devices be carried in conductive plastic bags. When adjusting or performing any
work on such assemblies, grounded work stations and wrist straps must be used. If soldering
irons are used, they must also be grounded.

A grounded work station is any conductive or metallic surface connected to an earth ground,
such as a water pipe, with a 1/2 to 1 megohm resistor in series with the ground connection. The
purpose of the resistor is to current limit an electrostatic discharge and to prevent any shock
hazard to the operator. The steps indicated above must be followed to prevent damage and/or
degradation, which may be induced by ESD, to static sensitive devices.

Wiring for immunity compliance

In applications where either the power, input or output wiring are subject to electromagnetic
disturbances, shielding techniques will be required. Grounded metal conduit with conductive
conduit fittings is recommended.

Connect the ac mains through a fused disconnect switch. To ensure that the unit meets the
requirements of the EMC directive 89/336/EEC, a power line filter kit is included with each unit.
Wind three turns of each wire (14 AWG maximum) through the filter core for the two power and
protective earth leads as illustrated in Figure 4-1. The wound filter cores shall be located
external to the 9782 case within 25 cm.

Conform to code

Instrument wiring should conform to regulations of the National Electrical Code.

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