presentation : ims – tech managers conferenceauthor : ims staffcreation date : 08 march...

Presentation : IMS – Tech Managers Conference Author : IMS Staff Creation date : 08 March 2012 Classification : D3 Conservation : Page : 1 05 - Wiring Methods and Practices Author : IMS Stafff Creation date : 1 Nov 2012 Classification : D3

05 - Wiring Methods and Practices


The intent of this presentation is to present enough information to provide the reader with a fundamental knowledge of the wiring methods and practices used within Michelin and to better

understand basic system and equipment operations.



Wiring Practices

• Terminal blocks shall be wired and mounted so the internal and external wiring does not cross over the terminals.

• No more than one conductor shall be terminated at each terminal block connection.

• Terminal blocks should be numbered in numerical ascending order from left to right.

• Terminal blocks for power circuits shall be grouped separately from control circuits.

• Conductors and cables shall be run from terminal to terminal without splices or joints.

• There should be no exposed live parts when the disconnecting means is in the open position.

• Alternating current (AC) control voltage shall be 120 volts or less, single phase.

• Grounded control circuits only shall be permitted.



Wiring Practices

• Terminal X2 shall be connected to the grounding conductor. Ground faults on any control circuit shall not cause unintentional starting or dangerous movements, or prevent stopping of the machine

• A Neutral Link shall be inserted between X2 and wire # 2.

• Ring connectors shall be used to connect conductors to non-captive type terminals.

• Cable ends shall be used on each conductor attached to a terminal strip (power or control)

and any other connections that are captive.

• All grounding conductors shall be terminated individually on the ground bar, using tapped

connections.

• Switch symbols shall be shown on the electrical schematic diagrams with all utilities turned off

(electric power, air, water and lubricant), the machine and its electrical equipment in its normal starting conditions. (Home Position)



Wiring Practices

• Symbols for devices shall be identified by a number-letter combination, using designations shown below:

Control Relay = *CR

Motor Starter = *M

Limit Switch = *LS



Identification of Conductors

• Conductors shall be identified at each termination by number, letter, color, and shall correspond with the technical documentation.

• Each conductor shall have the same identification at all terminals and tie points

• The color GREEN with or without YELLOW stripes shall be used to identify the equipment

grounding conductor where insulated or covered.

• Where an AC circuit includes a grounded conductor (current-carrying) (neutral), this conductor

shall be WHITE.

• Where a DC circuit includes a grounded conductor (current-carrying), this conductor shall be

White with Blue stripe.

• Ungrounded circuit conductors that remain energized when the supply disconnecting means

is in the off position shall be consistently applied as either ORANGE or YELLOW.




The use of other colors for the purpose of identification shall be as follows:

BLACK for Line and load circuits, AC or DC 150 volts and above

RED for ungrounded AC control conductors less than 150 volts

BLUE for ungrounded DC control conductors




The use of other colors for the purpose of identification shall be as follows:

BLACK for Line and load circuits, AC or DC 150 volts and above

RED for ungrounded AC control conductors less than 150 volts

BLUE for ungrounded DC control conductors

Identification of Pushbuttons

Stop button operators shall be colored RED and of the extended or unguarded type

Start button operators shall be colored BLACK and of the fully guarded type

Emergency pushbutton operators shall be of the lock-off (détente) self-latching mushroom operator type.

All pushbuttons shall be mounted above or to the left of their associated stop pushbuttons.



Conductors Sizes

Conductors shall not be smaller than:

Power circuits #14 AWG.

Control circuits #16 AWG.



Electrical Connections

Use of cable ends

Cable ends are to be used wherever theterminals are equipped with captive devices.

Use of ring type pressure connectors

Electrical connections to transformers,ground busses, motors and similar deviceswithout captive type devices shall be madewith ring type pressure connectors.

captive device



Crimping of Connections

CRIMPING

The striped wire should be pushed completely in the luguntil the wire insulation is stopped by the metal part of the lug.(Point A on the figure) Not more than one wire per lug.

The first crimp bonds the metal ofthe terminal to the conductor.

The second crimp function is tobond the terminal insulation to theconductor insulation.

Good crimping will be accomplished when:

1 - the metal part of the lug is crimped on the conducting part of the wire.

2 - the insulation part of the lug is crimped on the insulation part of the wire.

A



Conductor Identification

1

3

1

3

1

3

3

PLASTIC SLEEVE

WIRE MARKER

TERMINAL WIRENUMBERS

LEFT HEAD RULE0.25

1

33

1

1



Grounding

• There shall be a connecting bar (ground buss) for all grounding conductors in the circuit.

• All of the grounding conductors for the inside of the control panel will terminate on the top of

the ground buss.

• All of the grounding conductors for the components outside of the control panel will terminate

on the bottom of the ground buss.

• If the enclosure has a hinged door the continuity of the grounding circuit shall be insured by

bonding straps.

• The secondary of the control transformer (X2) shall be connected directly to the top of the

ground buss.



Grounding

• The back plane of the control panel must be bonded to the grounding buss. The din channel for the terminal strip must have an electrical bond to assure that the back plane is at the same potential as ground. This is insured by use of tapped screw connections between the din channel and the backplane.

• The liaison between the metal frame of all electrical components and the ground circuit must

be done with a copper grounding conductor (green or green with a yellow stripe). This applies to the following components:

• Motor housing ground will be connected

inside the terminal box at the motor• Pushbutton station enclosures and covers shall

be connected as illustrated• Limit switch enclosures shall be connected

as illustrated

XC

K - L

ZC

K - D

15

ZC

K - L1



Grounding

Cable Tray

ON

OFF

TelemecaniqueTC TelemecaniqueTC

1PB

3PB 4PB

2PB

This connector (green & yellow) is connected to earth ground



Lockout/Tagout/Tryout Procedure

Purpose and Scope - The purpose of this procedure is to specifically outline the steps to be taken during training with EMI/NA. This procedure is designed for EMI/NA training only and is not intended to be interpreted as the official procedure of any other plant or department.

Responsibility - It is the responsibility of the instructors to train all trainees on the lockout procedures. It is the responsibility of the trainees to comply with this procedure when doing any work that involves electrical circuits training or otherwise.

Lockout Tags - Lockout tags and locks shall be stored in the individual tool drawers and a responsibility of the trainees.

Procedure - The following procedure shall apply to cases where equipment or systems are to be serviced or repaired which will expose personnel to the hazards of moving machinery, energized electrical circuits, or hydraulic/pneumatic circuits. This procedure also applies to electrical training panels and fault finding machines that are not running.




1. Prior to shutting down any equipment, inform the person responsible for that particular area.

2. Trainees shall lock out all necessary systems to make the machine safe. After locking out the main electrical disconnect, the disconnect means shall be tested to ensure that it cannot be moved from the locked position.

• Verify the meter is operational by testing on a known live circuit• Locate and open proper disconnect means for desired circuit• Lockout the disconnect means• Verify absence of voltage at first entry point on the control panel

• 3 – phase to phase measurements• 3 – phase to ground measurements

• Try to operate the equipment




3. Distribution Panels - Motors and/or equipment such as lighting and receptacle circuits that are not supplied through safety disconnect switches shall be locked out only by qualified instructors.

4. Special Training Equipment - Equipment that is used for electrical training shall be supplied through a fused disconnect switch. These disconnect switches may only be placed in a "run" condition when trouble-shooting or function tests are being carried out.

5. Removal of Locks - In general, the removal of a lockout lock can only be done by the person who has installed the lock.

Note: In the event that a lock has to be cut off because of a lost key, or because the person responsible cannot be reached, approval must be obtained from the electrical instructor before the lock can be removed.

presentation : ims – tech managers conferenceauthor : ims staffcreation date : 08 march...

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