Technician Training: Wiring Basics

o Conduit – Materials & Junction Boxes

o Wire & Cable – Material & Types

o Color Conventions

o Number Conventions

o Termination – Methods

o Organization & Protection – Reasoning & Methods

o Pumps, Motors & Valves – Instructions

o Sensors & Data Communication – Standards & Instructions

Wiring Basics

Wiring Basics – Conduit

o Common Conduit Types:

PVC - Plastic for underground use

EMT - Metal tube conduit for standard commercial use

RGS - Rigid Conduit for industrial, exterior, & hazardous area use

FMC - Flexible metal conduit typically with plastic waterproof jacket (seal tight), usually maximum of 3-5 feet runs

o Conduit accessories and junction boxes may be plastic, light duty metal, or cast aluminum

May be standard/waterproof or UL listed for hazardous area

o Jobsite project standards determine conduit/box type

Wiring Basics – Wire & Cable

o Power & Signal wires are standard THHN stranded copper wire rated at 600VAC

THHN is oil and gasoline resistant and the stranded is important for terminating in panel terminal blocks

o Cable should also consist of stranded copper conductors within an oil and gas resistant jacket (Kynar)

o Ethernet cables for data communication should be CAT 5/6 with a PVC jacket suitable for industrial use

Wiring Basics – Color Conventions

o Color standards for wiring:

Green Ground White Neutral Black/Red 120 VAC Power and Signal Blue 24 VDC Power and Signal Brown/Yellow/Orange 480 VAC Power Other Colors Signal Wires

o Wires within a conduit should be numbered consecutively at each end –Temporary wire markers are commonly used for this purpose

o Wires should be permanently labeled with adhesive labels at each end –The numbering convention is the number of the terminal block in the panel

Wiring Basics – Number Conventions

Wiring Basics – Terminations

o Wires should be stripped and secured in the panel terminal blocks with no exposed copper conductors

Ground conductors may be exposed at lug connection

o Wire termination fittings are not typically needed for panel terminations

Crimp style spade and ring terminals are often needed for wire terminations at sensors and devices

o Standard wire nuts are used at motors and other devices as needed

Waterproof connectors or gel packs should be considered where wires could be exposed to water

o Wire installation should be inspected to assure protection at conduit entries with plastic bushings

o Wires within panels and junction boxes should be secured in logical bundles with tie wraps, while removing all electrical tape

o Install wiring within plastic wiring ducts where provided

o Cable troughs are used at a series of control panels

These are used for separate instrumentation and communication wiring from power wiring

Wiring Basics – Organization & Protection

o Pump motors wiring schematic

Attached to the body of the motor and indicate the termination of the power wires (ground wires attached to a bolt secured to the motor body)

o Motors for positive displacement and centrifugal pumps are usually supplied as dual voltage

1 Phase motors can be wired as: 120VAC (low voltage) or 208-230 VAC (high voltage)

3 Phase motors can be wired as: 240VAC (low voltage) or 480 VAC (high voltage)

o Motor / Pump Rotation

Our std. motors allow for rotation in either direction to suit the pump req.

For 1 Phase interchange wires 5 & 8, for 3 Phase interchange any 2 power leads

Wiring Basics – Pump Motors

Wiring Basics – Actuated Valves

o Wiring includes: 6 Wires plus ground & #14 AWG wire

o Wiring schematic inside the housing of the actuator Important to check this schematic because it may differ from generic

valve data sheets

o Limit Switch Feedback Wiring 1 Neutral 2 120 or other power to close 3 120 or other power to open 4 COM wire for limit switches unless internal line power used 5 Close limit switch signal 6 Open limit switch signal G Ground

Wiring Basics – Solenoid Valves

o Basics – Normally Open or Close, require 2 wires and sometimes a ground (for 120VAC the wires are 120VAC power and neutral)

o Mechanics – Panel operates a relay to send power to the panel to energize the valve and change state

When De-energized the valve return to its normal position

Continuous operation is advised against due to the vibration and heat generated during usage

o Relays isolate the solenoid from the PLC

Power to solenoid is typically fused, so shorts will not effect the PLC

Wiring Basics – On/Off Sensors

o Example of On/Off Sensors:

Level Switches, Leak Sensors, Flow Switches, Pressure Switches, Current Sensors, & Low-High Outputs from other panels

o Mechanics – The control panel sends out voltage to the sensor, the sensor changes states, which changes the status of the PLC input (used in logic)

o Many On/Off sensors (level-leak-flow) are reed switches

Thin metal elements which are drawn into contact with a magnet to complete a circuit

Reed switches are sensitive to over-current damage

Ground fault because of wire damage/bad connections/water

o Analog Sensors: transmitters for level, pressure, temperature & flow

0-10VDC or 4-20mA output, input is typically 24VDC

o Loop Power

2 wires (+ and -) power the device and provide a signal

Other sensors require 3 wires for power( +,-,signal)

o Wired with stranded THHN or more commonly jacketed cable

Twisted wires and shielding increase signal integrity

Wiring Basics – Analog Sensors

o RS-232 & RS-485 Circuit require twisted and shielded cables, 18-22 AWG conductors

o Ethernet CAT5 or CAT6 with industrial outer jacket Ethernet cables require special RJ-45 connectors on each end

1 Orange/White 2 Orange 3 Green/White 4 Blue 5 Blue/White 6 Green 7 Brown/White 8 Brown

o Data Cables should be in a separate conduit than power/signal

Wiring Basics – Data Communications