electrical safety for construction. electrical regulations v subpart k of 29 cfr 1926 1a
TRANSCRIPT
Electrical regulationsElectrical regulations
Part I - Safety requirements for Part I - Safety requirements for installing/using equipmentinstalling/using equipment• approval of electrical componentsapproval of electrical components• examination, installation, use of examination, installation, use of
electrical equipmentelectrical equipment• guarding of electrical equipmentguarding of electrical equipment• overcurrent protectionovercurrent protection• grounding of equipmentgrounding of equipment
1b
Electrical regulationsElectrical regulations
Part II - Safety-related work Part II - Safety-related work practicespractices• protection of employeesprotection of employees• passageways and open spacespassageways and open spaces• lockout/tagging of circuitslockout/tagging of circuits
1c
Electrical regulationsElectrical regulations
Part III - Safety-related Part III - Safety-related maintenance and environmental maintenance and environmental considerationsconsiderations• protection of wiring componentsprotection of wiring components• environmental deterioration of environmental deterioration of
equipmentequipment
1d
Electrical regulationsElectrical regulations
Part IV - Safety requirements for Part IV - Safety requirements for special equipmentspecial equipment• batteries and battery chargingbatteries and battery charging• PPEPPE• emergency eyewash stationsemergency eyewash stations
1e
How electricity worksHow electricity works
Current flows from a generating Current flows from a generating source through conductors, to a source through conductors, to a loadload
Complete Complete circuits are circuits are neededneeded
2a
How electricity worksHow electricity works
Normal route is through Normal route is through conductorsconductors
Shock occurs Shock occurs when the body when the body becomes a becomes a part of the part of the electrical electrical circuitcircuit
2b
I = Current (amperes)I = Current (amperes)
E = Voltage (volts)E = Voltage (volts)
R = Resistance (ohms) R = Resistance (ohms)
EI R
Ohm’s LawOhm’s Law
Body AreaBody Area OHMSOHMSDry SkinDry Skin 600,000 600,000
Wet SkinWet Skin 1,000 1,000
Internal OrgansInternal Organs 400-600400-600
Ear to EarEar to Ear 100 100
Human ResistanceHuman Resistance
50 Volts50 Volts
1,000 OHM1,000 OHM = .05 amps (50 mA)= .05 amps (50 mA)
50 Volts50 Volts
100 OHM100 OHM = .5 amps (500 mA)= .5 amps (500 mA)
Fatalities at 50 VoltsFatalities at 50 Volts
Electric shockElectric shock
Occurs when current enters the body Occurs when current enters the body at one point and exits at anotherat one point and exits at another
Shock occurs when you touch:Shock occurs when you touch:• both wires of an electric circuit;both wires of an electric circuit;• one wire of an energized circuit and one wire of an energized circuit and
ground; orground; or• a metallic part that is “hot”a metallic part that is “hot”
3a
Electric shockElectric shock
Severity of shock depends on the:Severity of shock depends on the:• amount of currentamount of current• path of the currentpath of the current• amount of time amount of time
exposedexposed
3b
Electric shockElectric shock
Effects range from a tingle, to Effects range from a tingle, to cardiac arrest, severe cardiac arrest, severe burns, and probable burns, and probable deathdeath
Typical household Typical household current of 15 amps current of 15 amps can cause deathcan cause death
3c
Electricity’s Physiological Electricity’s Physiological EffectEffect
00.001 amps00.001 amps 00.015 amps00.015 amps 00.020 amps00.020 amps 00.10000.100 01.20001.200 15.00015.000
Barely feltBarely felt ““let go” thresholdlet go” threshold Muscular paralysisMuscular paralysis Ventricular Ventricular
fibrillationfibrillation 100 Watt light bulb100 Watt light bulb Common household Common household
fusefuse
1-8 mA = shock, not painful1-8 mA = shock, not painful
8-15 mA = Pain8-15 mA = Pain
15-20 mA = Muscle contraction15-20 mA = Muscle contraction
20-100 mA = Severe pain & paralysis 20-100 mA = Severe pain & paralysis of breathing muscles of breathing muscles
100-1000 mA = Ventricular fibrillation100-1000 mA = Ventricular fibrillation
(Usually cause death)(Usually cause death)
> 1,000 mA = Heart stops> 1,000 mA = Heart stops
Effects of CurrentEffects of Current
GroundingGrounding
Protects you from electrical shockProtects you from electrical shock
Safeguards Safeguards against fireagainst fire
Protects electrical equipment from Protects electrical equipment from damagedamage
4a
GroundingGrounding
Two types of grounding include:Two types of grounding include:• Service or system Service or system
groundground• Equipment groundEquipment ground
4b
Circuit protective devicesCircuit protective devices
At construction sites, the most At construction sites, the most common electrical hazard is the common electrical hazard is the ground fault electrical shockground fault electrical shock
OSHA requires either:OSHA requires either:• Ground fault circuit interrupters Ground fault circuit interrupters
(GFCIs); or(GFCIs); or• Assured Grounding Conductor ProgramAssured Grounding Conductor Program
5a
Circuit protective devicesCircuit protective devices
Circuit protective devices include:Circuit protective devices include:• fuses and circuit breakers - protect fuses and circuit breakers - protect
conductors and equipmentconductors and equipment• GFCIs - limit or shut off current flowGFCIs - limit or shut off current flow
5b
Ground fault circuit Ground fault circuit interruptersinterrupters
A fast-acting circuit breaker that A fast-acting circuit breaker that senses small imbalances in the senses small imbalances in the circuit caused by current leakage circuit caused by current leakage to groundto ground
6a
Assured Equipment Assured Equipment Grounding Conductor Grounding Conductor programprogram
If GFCIs are not used, employers If GFCIs are not used, employers must have a scheduled and must have a scheduled and recorded Assured Equipment recorded Assured Equipment Grounding Conductor programGrounding Conductor program
7a
The AEGC program is an inspection The AEGC program is an inspection program covering:program covering:• all cord setsall cord sets• receptacles that are not part of a receptacles that are not part of a
permanent wiring structurepermanent wiring structure• equipment connected by cord and equipment connected by cord and
plugplug
7b
Assured Equipment Assured Equipment Grounding Conductor Grounding Conductor programprogram
Equipment must be visually Equipment must be visually inspected for damage/defects inspected for damage/defects before each day’s usebefore each day’s use
7c
Assured Equipment Assured Equipment Grounding Conductor Grounding Conductor programprogram
Tests must be performed:Tests must be performed:• before the first use of new equipmentbefore the first use of new equipment• after suspected damage to equipmentafter suspected damage to equipment• at three month intervalsat three month intervals
– continuity testcontinuity test– grounding conductor testgrounding conductor test
7d
Assured Equipment Assured Equipment Grounding Conductor Grounding Conductor programprogram
Lockout/TagoutLockout/Tagout
Electrical equipment deactivated for Electrical equipment deactivated for repair must be locked out and repair must be locked out and tagged at the point where it can be tagged at the point where it can be energizedenergized
Protects maintenance workersProtects maintenance workers
Warns others that work is being Warns others that work is being performedperformed
8a
Lockout/TagoutLockout/Tagout
Only the person who locked/tagged Only the person who locked/tagged the equipment can turn it back onthe equipment can turn it back on
Before equipment is energized, a Before equipment is energized, a qualified person must conduct qualified person must conduct tests and visual inspectionstests and visual inspections
8b
Lockout/TagoutLockout/Tagout
Each lock/tag must be removed by Each lock/tag must be removed by the person who applied itthe person who applied it
8c
Lockout/TagoutLockout/Tagout
If the employee is absent, the If the employee is absent, the lock/tag can be removed by a lock/tag can be removed by a qualified person if:qualified person if:• the employee who applied the lock the employee who applied the lock
has left the premiseshas left the premises• it is visually determined that all it is visually determined that all
employees are clear of the employees are clear of the circuits/equipmentcircuits/equipment
8d
Guarding requirementsGuarding requirements
Any live parts of electrical Any live parts of electrical equipment operating at 50 volts or equipment operating at 50 volts or more must be guarded to avoid more must be guarded to avoid accidental contactaccidental contact
9a
Guarding requirementsGuarding requirements
Entrances to areas with live Entrances to areas with live electrical parts must be marked electrical parts must be marked with warning signswith warning signs
Signs should Signs should forbid entrance forbid entrance except by except by qualified personsqualified persons
9b
InsulationInsulation
Check equipment daily for Check equipment daily for insulation breakdowninsulation breakdown
Check for:Check for:• exposed wiresexposed wires• broken wiresbroken wires• scuffed insulation on extension cordsscuffed insulation on extension cords
10a
InsulationInsulation
Use non-conducting mats, shields, Use non-conducting mats, shields, or barriers when necessaryor barriers when necessary
Use non-Use non-conducting conducting coatings on coatings on hand toolshand tools
10b
Personal protective Personal protective equipmentequipment
Employers must provide electrical Employers must provide electrical protective equipment to protective equipment to employees employees who work near who work near electrical electrical hazardshazards
11a
Personal protective Personal protective equipmentequipment
Use appropriate equipment for the Use appropriate equipment for the hazards, including:hazards, including:• helmetshelmets• eye and face eye and face
protectionprotection• gloves and gloves and
sleevessleeves• apronsaprons• protective footwearprotective footwear
11b