methods of control

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Methods of ControlModule 4

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Recognize

Control

Evaluate

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Identify the three types of control that should be used to achieve electrical safety.

Module Objectives

Identify the engineering, administrative and PPE controls you use on your job.Identify facts and procedures relating to lockout/tagout.

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Module Objectives

Recognize when a work permit is required to work on energized electrical circuits.

List the steps required to achieve an electrically safe condition.

Recognize the appropriate warning signs to alert employees to the danger of electricity.

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Recognize the appropriate PPE to use based on the calculated energy value of an energy source.

Module Objectives

Given a case study, determine the most appropriate method of control and necessary corrective action.

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A control is a measure or an action that is taken to eliminate current hazards and to prevent

future hazards.

What is a Control?

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Engineering

Three Types of Control

PPE

Administrative

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Controls that are engineered into the job. The focus is on

eliminating the hazard altogether.

Engineering Controls

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Redesign of equipmentSubstitution of material, equipment or processChange process to eliminate exposureUse of barriers to isolate the hazardUse of barriers or shields to isolate the worker

Engineering Control Examples

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Safe WiringChoose the correct size of wire for the amount of current in the circuit.Make certain that the wire’s insulation is appropriate for the voltage.Make sure the wire is tough enough for the conditions.Make sure the connection is reliable.Make sure the connections are protected.

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Wire Sizes

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Controls that reduce employee exposures

through administrative methods. Depend on

constant implementation or intervention.

Administrative Controls

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Education and trainingProcedures to limit exposureMaintenanceGood housekeepingSigns and warningsDistance

Administrative Control Examples

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Controls that are worn by employees to

protect them from the environment.

Personal Protective Equipment (PPE)

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Protective ClothingProtective Gear

PPE Examples

Photo courtesy of Schneider Electric

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Uncontrolled Arc Blast

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Arc Blast Controls

EngineeringAdministrativePPE

Photo courtesy of Schneider Electric

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Arc Blast With Circuit Breaker

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Comparison of BlastsBoth Blasts: 480 Volts, 30,000 Amps

Uncontrolled Blast Circuit Breaker BlastCircuit opened in 330 millisecondsIncident energy = 30 calories per cm2

Circuit opened in 8 millisecondsIncident energy = .30 calories per cm2

Circuit breaker = energy reduction factor of 100!

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What is Lockout/Tagout?

Photo courtesy of Schneider Electric

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The placement of a lockout device on an energy isolating device, in accordance with an established

procedure, ensuring that the energy isolating device and the equipment

being controlled cannot be operated until the lockout device is

removed.

Lockout

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The placement of a tagout device on an energy isolating device, in

accordance with an established procedure, to indicate that the energy

isolating device and the equipment being controlled may not be operated

until the tagout device is removed.

Tagout

DANG

ER

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1910.147 Versus 1910.3331910.147 1910.333

Equipment that might unexpectedly energize

When

Who

Verifi-cation

Energized circuits

Authorized person Qualified person

Verifies isolation and de-energization

Tests for energized condition due to inadvertant voltage or voltage backfeed

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Achieving an Electrically Safe Condition

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Warnings and Signs

Slide courtesy of Schneider Electric

Illustrates minimum requirement.This is an example, not a

recommendation.

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Warnings and Signs

Slide courtesy of Schneider Electric

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The Importance of PPE

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S a m p l e O n l y

Selecting PPE

OutputCategory PPE

0

1

2

3

4

Untreated cotton

FR shirt and FR pants

Cotton underwear plus FR shirt & FR pants

Cotton underwear plus FR shirt & FR pants plus FR coverall

Cotton underwear plus FR shirt & FR pants plus double layer switching coat and pants

Incident Energy

(Cal/cm2)

N/A

4

8

25

40

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Photo courtesy of Schneider Electric

PPE—Hand and Arm Protection

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Photo courtesy of Schneider Electric

PPE—Face, Hands, Arms, Torso

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Photo courtesy of Schneider Electric

PPE—Face, Hands, Arms, Torso

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Control Summary

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Electrical Controls—Case 1

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Electrical Controls—Case 2

Photo Source: NIOSH Safety and Health for Electrical Trades

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Electrical Controls—Case 3

Photo Source: NIOSH FACE Case 03NE022

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Electrical Controls—Case 4

Photo Source: NIOSH FACE Case 03NE022

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Planning for Your Small BusinessAction Potential

BarriersOvercoming the Barriers