Guide Electricity

8/3/2019 Guide Electricity

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WORKSAFE WESTERN AUSTRALIA COMMISSION

ELECTRICITY: RESIDUAL CURRENT

DEVICES

Guidance Note

Occupational Safety and Health Regulations 1996

Regulation 3.60 Protection against earth leakage current

when portable equipment in use

March 1998


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SUMMARY

1. Regulation 3.60 applies to the use of portable electrical equipment used in allworkplaces, other than construction sites. Electrical equipment used on constructionsites is covered by regulation 3.61.

2. Regulation 3.60 requires the users of portable electrical equipment at workplaces tobe protected against earth leakage current by means of a residual current device(RCD).

3. Persons having control of the workplace are required to install non-portable typeRCDs. They have the choice of installing the RCD at the switchboard or in a fixed

socket outlet.

4. It must be readily apparent to the users of portable electrical equipment if and where

non-portable RCDs have been installed.

5. If it is not readily apparent or the user is uncertain whether an RCD has been

installed, a portable RCD must be provided by the employer and must be used by theemployee.

6. This guidance note is issued by the WorkSafe Western Australia Commission toprovide information and advice on the duties of employers, employees, self-employed

persons and persons having control of workplaces under the Occupational Safetyand Health Act 1984 in relation to the use of portable electrical equipment andmeeting the requirements of regulation 3.60 of the Occupational Safety and Health

Regulations 1996.


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GUIDANCE NOTE ELECTRICITY: RESIDUAL CURRENT DEVICES PAGE: 130 MARCH 1998

1. INTRODUCTION

Electricity is a common workplace hazard, and is a frequent cause of electricshocks. Some of these shocks have been fatal.

Electricity does not have to be high voltage for an electrocution to occur.

Electrocutions have resulted from contact with faulty electrical equipment thathas become live, or contact with worn and damaged wiring and switches.

While there are many different causes of electrocution, all have one thing incommon they could be prevented.

In 1992 Worksafe Australia found that of 95 workplace deaths due toelectricity recorded in a work-related fatalities study, 36 deaths or more than

half of those not caused by aerial powerlines would probably have beenprevented by the use of RCDs.

The Worksafe Australia study recommended, among other strategies, the useof RCDs in homes and workplaces. This approach was endorsed by theWorkSafe Western Australia Commission. Specific requirements for RCDs to

protect users or operators of portable electrical equipment were included in the

Occupational Safety and Health Regulations 1996.

This guidance note was developed within the tripartite WorkSafe WesternAustralia Commission, with input from representatives of employerorganisations, trade unions and Government. It is published by the WorkSafe

Western Australia Commission to provide detailed information to assist

employers, self-employed persons, persons having control of workplaces andemployees, in meeting their duties under the Occupational Safety and Health

Act 1984 and the requirements of regulation 3.60 Protection against earth

leakage current when portable equipment in use.

2. LEGISLATION REQUIRING RCDs

The Occupational Safety and Health Regulations include specific requirements toprotect users or operators of portable electrical equipment. Regulation

3.60 Protection against earth leakage current when portable equipment in useis designed to minimise the risk of a person receiving a harmful or fatal electricshock when using portable electrical equipment. Regulation 3.60 does notapply to construction or demolition sites.

Regulation 3.61 Electrical installations on construction sites requireselectrical installations on construction sites to comply withAustralian and New

Zealand Standard AS/NZS 3012 Electrical installations Construction and

demolition sites. AS/NZS 3012 covers the provision of RCDs on constructionand demolition sites.


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PAGE: 2 GUIDANCE NOTE ELECTRICITY: RESIDUAL CURRENT DEVICES30 MARCH 1998

Protection against earth leakage current when portable equipment in use

Regulation 3.60 states

(1) This regulation applies to a workplace other than one to whichAS/NZS 3012 applies

but does not apply to a workplace at which the supply of electricity

(a) does not exceed 32 volts alternating current;

(b) is direct current;

(c) is provided through an isolating transformer complying withAS/NZS 3108; or

(d) is provided from the unearthed outlet of a portable generator.(2) In this regulation

hand-held equipment means portable equipment

(a) of a kind that is intended to be held in the hand during normal use; and

(b) the motor, if any, of which forms an integral part of the equipment;

portable equipment means equipment that is

(a) connected to an electricity supply; and

(b) intended to be moved when it is in use,

and includes, but is not limited to, hand-held equipment;

workplace means a workplace to which this regulation applies.

(3) A person having control of a workplace

(a) must ensure that each non-portable residual current device installed at the

workplace is kept in a safe working condition and tested on a regular basis to

ensure its continued effective operation;

(b) must provide, where electricity is supplied to portable equipment through a

fixed socket at the workplace after 31 March 1998, protection against earth

leakage current by means of

(i) a non-portable residual current device installed at the switchboard; or

(ii) by a non-portable residual current device built into a fixed socket

which, having regard to the primary use of the socket and its location,

is likely to be used by a person operating portable equipment; and

(c) must ensure where a non-portable residual current device has been

(i) installed at a switchboard, that a notice is displayed in a prominent

place at or near the switchboard indicating that a non-portable residual

current device has been installed at the switchboard; or

(ii) built into a fixed socket, that the socket can be identified as providing

protection against earth leakage current.

Penalty: $25 000.

(4) A person who is an employer or a self-employed person at a workplace

(a) must ensure that each portable residual current device used at the workplace

by the person or an employee of the person is kept in a safe working condition

and tested on a regular basis to ensure its continued effective operation; and(b) where the employer or a self-employed person is not satisfied that protection

against earth leakage current has been provided by means of a non-portable

residual current device

(i) must provide a portable residual current device for use with each item

of portable equipment used by the person or an employee of the person

at the workplace after 31 March 1998; and

(ii) must ensure that a portable residual current device is directly

connected to the output side of a fixed socket when an item of portable

equipment is being used by the person or an employee of the person at

the workplace after 31 March 1998.

Penalty: $25 000.


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(5) An employee who is provided with a portable residual current device for use with an

item of portable equipment at a workplace must not use the portable equipment unless the

portable residual current device is directly connected to the output side of a fixed socket.

Penalty: $5 000.

3. DUTIES OF A PERSON HAVING CONTROL OF A WORKPLACE

Section 22 of the Occupational Safety and Health Act requires a person whohas, to any extent, control of a workplace to ensure, so far as is practicable,

that people who are at the workplace are not exposed to hazards. In manycases employers will have control over their premises thus having duties undersections 19, 21 and 22 of the Act. Persons having control of a workplace

include owners, lessors, etc. of premises, who may have no involvement withthe work activity at the premises, but who have retained some control over thepremises. For more information on the general duties of persons at the

workplace see the WorkSafe Western Australia Commission Guidance NoteGeneral Duty of Care in Western Australian Workplaces.

Regulation 3.60 requires a person having control of a workplace to provideprotection for the users or operators of portable electrical equipment against earthleakage current by means of a non-portable RCD.

The owner or the person managing a building on behalf of the owner, has thechoice of installing non-portable RCDs at the switchboard to protect all or selected

circuits only, or at fixed socket outlets. If the installation is at the switchboard, allthe wiring and appliances plugged into the circuit will be protected. The size of thebuilding, its use or any plans to refurbish, refit or rewire the building will influence

whether to install RCDs at the switchboard for complete or selected circuitprotection or at fixed socket outlets.

If an owner or manager chooses to have inbuilt RCDs in fixed sockets, not everyfixed socket has to be RCD protected. In deciding which fixed sockets are to haveinbuilt RCD protection, the likely use of the fixed socket has to be taken into

consideration. For example, conveniently located fixed sockets are the most likelyto be used by cleaners or maintenance personnel and should be protected with non-portable RCDs.

Cleaners and maintenance personnel may use up to 30 metres of extension cord orflexible supply cord between an RCD protected fixed socket and portableequipment. This distance of 30 metres may be used to assist in determining the

number and location of RCD protected fixed socket outlets to provide coverage forcleaners.

RCD protection at the switchboard must be identified by a notice displayed near theswitchboard. Where this protection is for selected circuits only, the socket outletsso protected must each be identified by a notice displayed at the socket outlet.

Where RCD protection has been built into a fixed socket, the fixed socket must beidentified as providing RCD protection.


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4. DUTIES OF AN EMPLOYER

Section 19 of the Occupational Safety and Health Act requires an employer toprovide, so far as is practicable, a workplace where employees are not exposed tohazards and to provide a safe system of work. In the case of using portable

electrical equipment the employer should establish whether the fixed socket outlets

to be used by his or her employees are protected by RCDs and whether they areidentified as being protected.

The employer must inform the employees if and where protection is provided. Ifthe employer is not satisfied that non-portable RCDs have been installed, the

employer should provide a portable RCD and consult with the employee on whenand where the portable RCD is to be used. If there is any doubt regarding theinstallation of RCDs at the workplace, portable RCDs must be provided and used.

The use of a portable RCD in a circuit already protected by a non-portable (orportable) RCD has no detrimental effect on the operation of either RCD.

5. DUTIES OF EMPLOYEES

Under section 20 of the Occupational Safety and Health Act, employees have aduty to take reasonable care of their own safety and avoid harming the safety or

health of other people. Before connecting portable electrical equipment to anelectrical power source, an employee should seek the advice of the employer as towhether the outlets are protected by non-portable RCDs. Where neither the

employer nor an employee is satisfied that non-portable RCDs have been installed,the employer must provide a portable RCD. The employer and the employeeshould consult on when and where the portable RCD is to be used.

6. WHAT IS A RESIDUAL CURRENT DEVICE [RCD]

RCDs are often known by other names, eg., earth leakage circuit breakers(ELCB) or safety switches.

An RCD is an electrical safety device specially designed to immediately switchthe electricity off when electricity leaking to earth is detected at a level

harmful to a person using electrical equipment. An RCD offers a high level ofpersonal protection from electric shock. Fuses or overcurrent circuit breakersdo not offer the same level of personal protection against faults involving

current flow to earth.

Circuit breakers and fuses provide equipment and installation protection and

operate only in response to an electrical overload or short circuit. Short circuitcurrent flow to earth via an installations earthing system causes the circuitbreaker to trip, or fuse to blow, disconnecting the electricity from the faulty

circuit.


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However, if the electrical resistance in the earth fault current path is too high toallow a circuit breaker to trip (or fuse to blow), electricity can continue to flow

to earth for an extended time. RCDs (with or without an overcurrent device)detect a very much lower level of electricity flowing to earth and immediatelyswitch the electricity off.

RCDs have another important advantage - they reduce the risk of fire by

detecting electrical leakage to earth in electrical wiring and accessories. This isparticularly significant in older installations.

Residual Current Device (RCD) Fuses Circuit Breakers

RCDs work on the principle What goes in must come out. They operate bycontinuously comparing the current flow in both the Active (supply) and

Neutral (return) conductors of an electrical circuit.

If the current flow becomes sufficiently unbalanced, some of the current in the

Active conductor is not returning through the Neutral conductor and is leakingto earth.

RCDs are designed to operate within 10 to 50 milliseconds and to disconnectthe electricity supply when they sense harmful leakage, typically 30 milliamps.

The sensitivity and speed of disconnection are such that any earth leakage willbe detected and automatically switched off before it can cause injury ordamage. Analyses of electrical accidents show the greatest risk of electric

shock results from contact between live parts and earth.

Contact with live parts may occur by touching:

* bare conductors;* internal parts of an appliance; or* external parts of an appliance that have become live because of an

internal fault.

Contact with earth occurs through normal body contact with the ground orearthed metal parts.

An RCD will significantly reduce the risk of electric shock, however, an RCDwill not protect against all instances of electric shock. If a person comes into

contact with both the Active and Neutral conductors while handling faultyplugs or appliances causing electric current to flow through the persons body,this contact will not be detected by the RCD unless there is also a current flow

to earth.


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On a circuit protected by an RCD, if a fault causes electricity to flow from theActive conductor to earth through a persons body, the RCD will automatically

disconnect the electricity supply, avoiding the risk of a potentially fatal shock.

Fault current path/s to earth

7. TYPES OF RCDs

There are three types of RCDs switchboard mounted, powerpoint (GPO)type and plug in (portable). Switchboard mounted and powerpoint types are

referred to as non-portable RCDs. Portable RCDs are plugged into a fixedsocket. A non-portable RCD installed at the switchboard is the best option inmost situations as it protects all the wiring and appliances plugged into the

circuit, however, the regulation provides the option of providing non-portable

RCDs built into fixed sockets.

Switchboard Units

These are non-portable units installed at the switchboard to provide protection

of the complete installation, or protection of a selected circuit.

Switchboard RCD units.

These may be installed at the

main switchboard to provide RCD installed at the switchboard

complete installation protection

or selected circuit protection


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Fixed Socket Units

These are non-portable units consisting of RCD protection inbuilt into a fixedsocket outlet to provide protection to equipment plugged into the outlet.

RCDs incorporated in fixed sockets

provide single outlet or single

circuit protection. This type of unit

may be installed at selected

locations instead of providing

protection at the switchboard

RCD incorporated in fixed socket

Portable Units

These are to be used where doubt exists that non-portable RCD protection hasbeen provided. Various models are available from simple plug adaptors to

units designed for specific equipment such as the portable unit shown below orwired, by a licensed electrical worker, to an extension cord.

Portable RCD unit suitable for use with

extension cords and portable power tools

Portable RCD

plug adaptorPlug adaptor wired

to an extension cord

Portable RCD plugged into external power point


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8. SUPPLY OF ELECTRICITY WHERE REGULATION 3.60

DOES NOT APPLY

Regulation 3.60 states that the requirements of the regulation do not apply inthe following situations:

q Workplaces where AS/NZS 3012 appliesAS/NZS 3012 Electrical installations Construction and demolition sites,

specifies requirements for electrical installations which supply electricity to

appliances and equipment on construction and demolition sites, and for thein-service testing of portable, transportable and fixed electrical equipmentused on construction and demolition sites.

Regulation 3.61 Electrical installation on construction sites mandates

AS/NZS 3012. The requirements for RCD protection on construction sites

has been carried forward from the repealed Occupational Health, Safety

and Welfare Regulations 1988.

q Where the supply of electricity does not exceed 32 volts alternating current(AC) or is direct current (DC)

The severity of an electric shock depends upon the following factors:

- the magnitude and path of the current through the body;- the duration of the shock; and- the type of voltage supply, AC or DC.Alternating currents are much more likely to cause serious shocks thandirect currents of similar voltages. Alternating currents of even low value

exercise a paralysing effect upon the muscles causing the victims grip totighten, making self release difficult or impossible.

Most people will not be adversely affected at 32 volts AC. Alternatingcurrent of such low voltage is usually sourced independent of supply mains,or from the supply mains through an isolating transformer.

Electrocution from DC current is far less likely than with AC currentbecause with DC current it is easier to remove the grip on live parts and

because DC current has a lesser effect on the cardiac system. Direct

current, however, should always be treated with care.

q Where supply of electricity is provided through an isolating transformercomplying with AS/NZS 3108 or from the unearthed outlet of a portable

generator

An isolating transformer is a transformer designed to supply extra lowvoltage and low voltage circuits, the input windings being double insulated

(or equivalent insulation) from the output windings. Advice from a personcompetent in electrical installations should be sought regarding the need, orotherwise, for RCD protection of portable equipment supplied from

portable generators or through transformers.


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9. INSTALLING AND PROVIDING RCDs

The person having control of the workplace, eg., the owner of the property, or theperson managing the property on behalf of the owner has a responsibility to providenon-portable RCD protection at the switchboard to protect all or selected circuits

only, or in a reasonable number of fixed socket outlets in each section or area of the

workplace where portable electrical equipment is in regular use. These outletsmust be clearly identified.

If it is not readily apparent that non-portable RCDs have been installed at a fixedsocket or at the switchboard, the employer of persons using portable electrical

equipment must ensure the portable electrical equipment used by their employees isprotected by a portable RCD unit which is directly connected to the output side ofa fixed socket. The various types of portable RCDs are shown at Section 7.

Directly connected means there is no extension cord connecting the portable RCDto the output side of the socket or in the case of a portable RCD with a flexible

supply cord, no extension cord is used to connect the RCD to the socket. As theflexible supply cord is not RCD protected, its length should be as short as possibleand must not be increased beyond that supplied or specified by the manufacturer.

No additional extension cord is to be used to connect the RCD to the socket as thiswould increase the length of unprotected cord.

Non-portable RCDs must be installed by a licensed electrician or licensedelectrical in-house worker. Only a correctly installed RCD will provide therequired level of personal protection. It is a requirement of theElectricity Act1945 and Regulations that the installation must comply with

AS 3000 Electrical installations Buildings, structures and premises (knownas the SAA Wiring Rules).

Portable electrical equipment that is known to be damaged or faulty must notbe used until repaired by a licensed electrical worker.

10. EQUIPMENT REQUIRING RCD PROTECTION IN ACCORDANCE

WITH REGULATION 3.60

Portable equipment is defined as equipment that is

(a) connected to an electricity supply; and(b) intended to be moved when it is in use,

and includes, but is not limited to, hand-held equipment.

Hand-held equipment is defined as portable equipment

(a) of a kind that is intended to be held in the hand during normal use; and

(b) the motor, if any, of which forms an integral part of the equipment.


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Portable electrical equipment that requires protection includes, but is notlimited to, the following items which are intended to be moved whilst in use:

* hand-held power tools such as drills, saws, planers, grinders and

chainsaws;* power equipment such as jack-hammers and lawn mowers;* cleaning equipment such as vacuum cleaners and industrial polishers;

* hand-held appliances such as hair dryers and curling wands; and* cord extension leads connected to any of the above items (ie., portable

RCDs must also protect the cord extension lead).

The above items of portable equipment may be single phase or three phase.

RCD protection to some types of portable equipment will depend on thesituation in which the equipment is used. For example, in the entertainmentindustry, if any part of a sound system such as a microphone, is intended to be

held in the hand or moved when in use, that part of the system should beprotected by an RCD if it is powered by alternating current exceeding 32 volts.

Similarly, portable or stage lighting exceeding 32 volts which is hand held or

intended to be moved when in use should be RCD protected.

RCD protection is not required if power is supplied through an isolatingtransformer complying with AS/NZS 3108.

Appliances which are double insulated (clearly marked with the wordsDouble Insulated, or with the double square symbol o ) provide additional

protection against electrocution because of their construction. They protectthe user from receiving an electric shock from the casing of the equipment.

However, the flexible supply cord attached to the appliance or a cord extensionlead used is a potential source of electrocution and requires RCD protection.

11. EQUIPMENT TO WHICH REGULATION 3.60 DOES NOT APPLY

Electrical equipment that presents a very low risk includes, but is not limited to:

* desk top computers, computer printers and monitors;

* photocopiers;* refrigerators;

* television sets and VCRs;* equipment connected by fixed wiring; and* large stationary equipment connected by a flexible cord which is not

flexed during normal use, for example, a window-mounted air

conditioner.

RCDs are not suitable for providing protection from electric shock from thehandpiece of welding equipment. It is not feasible to provide RCD protection

to the welding handpiece since current leaking to earth in the circuit betweenthe electrode conductor and the return conductor will continually trip out an

RCD.


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However, the primary winding of the power source of the welding plant willrequire RCD protection if the welding plant is portable equipment intended to

be moved while in use. Portable RCD protection must be provided to anyportable or hand held electrical equipment which is supplied with electricityfrom a power outlet on welding equipment, unless the power outlet has inbuilt

RCD protection.

AS 1674 Safety in welding and allied processes Part 2: Electrical providesinformation on preventing electric shock in welding operations through sensiblepreventative measures involving inspection and maintenance of equipment, safeoperating procedures and safety precautions.

Medical equipment, where a trip out could be detrimental to a patient, shouldnot be RCD protected.

All portable electrical equipment should be regularly checked and tested in theworkplace by a competent person.

12. RISK ASSESSMENT OF OTHER EQUIPMENT

Electrical equipment that is not moved or carried while being operated presentsa very low risk of electric shock and while it is not required to be protected by

RCDs under the provisions of regulation 3.60, the equipment should beassessed in accordance with regulation 3.1.

Identification of hazards, and assessing and addressing risks, at workplaces

Regulation 3.1 states

A person who, at a workplace, is an employer, the main contractor, a self-employed

person, a person having control of the workplace or a person having control of access

to the workplace must, as far as practicable

(a) identify each hazard to which a person at the workplace is likely to be

exposed;

(b) assess the risk of injury or harm to a person resulting from each hazard,if any, identified under paragraph (a); and

(c) consider the means by which the risk may be reduced.

Penalty:$25 000.

Where an assessment under regulation 3.1 indicates a person using electricalequipment is at riskof receiving an electric shock, the use of an RCD should be

considered, and if appropriate, used as a means of reducing the risk. It ishighly probable the assessment will indicate electrical appliances and equipmentlikely to be used in a wet or hazardous environment may need to be protected.

In some situations these could include washing machines, kettles, frypans, jugsand ice making machines. The presence of moisture will increase the riskassociated with the use of electrical equipment.


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13. INSPECTION AND TESTING

Guidelines for inspection and testing of portable RCDs are provided in

AS 3760 In-service safety inspection and testing of electrical equipment.

AS 3760sets out, in table 1, the intervals between push button testing (by user)

and inspection testing for operation by an electrician for various types ofenvironments in which portable RCDs are used.

The information in AS 3760, table 1, is set out below.

Type of environment

in which equipment

Interval between inspection and tests for

portable RCDs

is usedPush-button test (by

user)

Test for operation(by licensed electrical

worker)

Factories, workshops andplaces of work of

manufacturing, repair,assembly, maintenance orfabrication

Daily, or before everyuse, whichever is the

longer

12 months

Other commercialenvironments with no

special protection, eg.,laboratories, tea rooms,office kitchens, and health

care establishments

3 months, or beforeevery use, whichever is

the longer

2 years

Office environment where

equipment is not subject toconstant flexing of thesupply cord

3 months 2 years

Hire equipment Before each hire Before each hire

Testing of non-portable RCDs at switchboards or inbuilt into socket outlets

must be carried out on a regular basis. This includes both push button testingby the user and inspection testing for operation by a licensed electrical worker.Unless operated from time to time, an RCD may mechanically freeze and not

trip when required.

Push-button testing by the user only confirms satisfactory mechanicalperformance of the tripping mechanism of the RCD. It does not replaceinspection testing for operation by a licensed electrical worker.


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As non-portable RCDs are far less susceptible to damage than portable RCDs, theyare not subjected to the same testing and inspection procedures. In the case of

non-portable RCDs, push button testing is recommended at three monthly intervals.

After tripping out, an RCD must be re-activated in accordance with a

"re-establishment of supply" procedure which requires the cause of the trip tobe established and remedial action taken before re-establishing the supply.

These procedures should bedrawn up by the employer after consultation withemployees and safety and health representatives, if any.


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PAGE: 14 GUIDANCE NOTE ELECTRICITY: RESIDUAL CURRENT DEVICES

OTHER PUBLICATIONS

The following publications can be purchased from WorkSafe Western Australia,

Westcentre, 1260 Hay Street, West Perth [Tel. (08) 9327 8777]:

q Occupational Safety and Health Act 1984;q Occupational Safety and Health Regulations 1996;q Codes of Practice published by the WorkSafe Western Australia Commission:

* Excavation;

* First Aid, Workplace Amenities and Personal Protective Equipment;* Legionnaires Disease;* Manual Handling;

* Management of HIV/AIDS, Hepatitis B & C at Workplaces;* Prevention of Falls at Workplaces; and* Styrene.

q Guidance Notes published by the WorkSafe Western Australia Commission:* The General Duty of Care in Western Australian Workplaces; and

* Election of Safety and Health Representatives, Representativesand Committees and Resolution of Issues.

These documents are also available via the Internet Service on Safetyline

[http://www.safetyline.wa.gov.au].

The following publications are under development or are expected to commencedevelopment during 1997/98 and when available will be listed in Whats New on the

Internet Service:

q Codes of Practice:* Abrasive Blasting;

* Control of Noise in the Music Entertainment Industry (Review);* Demolition;* Isocyanates;

* Legionnaires Disease (Review)

* Spraypainting;* Steelwork;

* Young Workers;

q Guidance Notes:* Competent Persons;* Powered mobile plant;

* Communication with isolated employees;* Registration of plant design;* Registration of individual items of plant.

Documents

Guide Electricity