dr david sweeting - update on arcing hazards

UPDATE ON ARCING HAZARDS by

Dr. David Sweeting Hon.F.I.E Aust

Senior member IEEE Visiting Professor University of Wollongong

Sweeting Consulting Pty Ltd

© ACN 003 795 257 Sweeting Consulting Pty Ltd

1

MY ACTIVITIES

• Working on an “Arc Hazards Guide” • Aim

– Part 1 deal will “legal issues” • Interpretation

– Part 2 is for a “worker” • What to do

– Part 3 is for an “expert” • Arc hazard exposure document

© ACN 003 795 257 Sweeting Consulting Pty Ltd 2

SAFE WORK AUSTRALIA

• Tripartite body of government, unions and

employers • In 2011 Model Work Health and safety (WHS)

Act • In 2011 Model Work Health and Safety

Regulations – Legally binding in some states – Except for “electrical supply authorities”


REGULATION 34 REQUIRES EVERYONE TO

IDENTIFY • Reasonably foreseeable electrical hazards

– Electrocution (ventricular fibrillation) – Electric shock (larger currents in body) – Arcing hazards (currents in the vicinity)

• HV electric shocks turn into arcing hazards

• Related hazards – Falling, Confined spaces, hazardous substances,

Flammable combustible substances


ARCING FAULT ELECTRICAL HAZARDS

• Contact with arc column (Very severe burns) • Clothing ignition/melting (Very severe burns) • Decaying plasma cloud (Severe burns) • Electrode metal spray (eye, skin burns) • Radiation (light) (Burns, T blindness) • Pressure waves (lung damage) • Falling, being struck (landing, physical)


REGULATION 35 REQUIRES

MANAGEMENT OF THE RISKS • So far as is reasonably practical (SFAIRP)

• This involves • (1) Eliminate risks SFAIRP • (2) Then Implement risk controls • (3) Minimise risk SFAIRP • Regulation 36 provides a list of how to

minimise SFAIRP


HIERARCHY OF CONTROL

MEASURES • (1) Eliminate risk

• (2) Implement risk controls • (3) Minimise risk • (3.1) substitute with lesser risk • (3.2) Isolate the hazard from the person • (3.3) Use engineering controls • Then (4.4) Use administrative controls • Finally (4.5) Provide suitable PPE


USA relative to AUSTRALIA

• Hierarchy of hazard controls – Similar wording

• NFPA70 (wiring rules) – Engineering controls

• NFPA70E (work procedures) – Reliance on PPE

• Desire for PPE to cover – Everything using NFPA70E or IEE1584


AS3000 CONSIDERS

• Ventricular fibrillation (Electrocution) • Excessive surface temperatures • Explosive gases and dust • arcing hazards (NOT really) • electric shock (NOT really)


PROHIBITED ELECTRICAL WORK ON

ENERGISED EQUIPMENT • Exposed parts are energised until isolated

• Exposed HV until earthed after isolation • Permits Testing to prove “NOT energized” • Silent on “operating work” • Many arcing faults occur during “operating

work”


PERMITTED ELECTRICAL WORK ON

ENERGIZED ELECTRICAL EQUIPMENT • Regulation 157 says this is:

• NOT allowed UNLESS – Necessary for health and safety – Necessary to do work properly – Necessary for testing for “dead” – No reasonable alternative – For a supply authority


SERIES OF REGULATIONS

• What you have to do WHEN • Working on “energized electrical equipment”


REGULATIONS SILENT ON

“OPERATING WORK” • Energize/de-energize

– (load make/break) – (fault make/break)

• Connect/disconnect – (isolating distance)

• Earth/de-earth – (fault rated earthing equipment) – (discharge rated earthing equipment)


“OPERATING WORK” IS PERMITTED

ENERGIZED WORK • Interest of Health and safety

• Necessary • No alternative


“OPERATING WORK” REQUIRES

• All Procedures of permitted energized work • Except a GPO or plug (Reg 146) • AS3000 compliant switchgear (shock/arcing

hazards)


ASSIGNMENT OF WORK

• “Specified mandated de-energized work” • “Specified permitted energized work”, • “Electrical work without a specified process”


ASSIGNED WORK CONTAINS

• “Mandated de-energized tasks” (MUTs) and, • “Permitted energized tasks”, (PETs)

– Energized work procedures

• and within each task there are: – Hazards that require identification, – With control measures required for each hazard


BASIC WORK PROCESS OF

UN-ENERGIZED WORK • Disconnect

• Isolate • Test for dead • Earth (HV) • MANDATED UN-ENERGIZED WORK • Remove earth (HV) • Test Insulation • De-Isolate • Reconnect and Energize


QUESTIONS


dr david sweeting - update on arcing hazards

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