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BASIC ELECTRICITY 101Kevin Booker, Executive DirectorState Electrical Division of Nebraska
Review some typical hazardsassociated with electricity andlearn how to mitigate thehazards.OBJECTIVES
In the United States,electrical hazards areranked number 6among all causes ofwork-related deaths.
Thefollowing drawing shows howcircuit breakers access theincoming power:SINGLE PHASE ELECTRIC PANEL
ELECTRIC PANELDouble PoleCircuit Breaker240vMain Power240v / 120v -1ØMain BreakerBus Bars240v CircuitSingle PoleCircuit Breaker120v120v CircuitNeutralGround
So a 2000 watt UPS will draw howmany amps?2000/120 16.66 ampsA standard 20 amps outlet isdesigned to carry 80%, thatwould be 16 amps.How much additional load will thiscircuit handle?I V/R
VentingRated ?Listed
NEC 110.13. Mounting and Cooling ofEquipment.This requirement is always in dispute, itseems. Cramming equipment into anovercrowded arrangement to maximizerevenue per square foot sounds like areally good idea until that equipmentstarts failing left and right, or the wholeplace just burns down.NATIONAL ELECTRICAL CODE
Do YOU push the test buttonon GFCIs and AFCIs monthly?It’s HARD to rememberwithout calendaring the task!
NEC 110.3. Examination, Identification,and Use of Equipment. This section gives8 requirements for examination in part(A). In (B), it says "Listed or Labeledequipment shall be installed and used inaccordance with any instructionsincluded in the Listing or Labeling."In other words, use the product asintended. Unauthorized modificationsvoid the Listing and expose the modifierto civil, and potentially criminal, litigationand liability.
Back in 2005 the CPSC (ConsumerProduct Safety Commission) went to theelectrical manufacturers of GFCI’s andasked them to develop self testingdevices.The original scope was that the devicewould shut down if it did not pass theself test and hence create the safetythat these devices are there to provide.
Section 1926.416(e)(1) provides that "wornor frayed electrical cords or cables shall notbe used." Superficial nicks or abrasions —those that only slightly penetrate the outerjacket of a flexible cord, and do not permitthe cord to bend more in that area than inthe rest of the cord — do not normallyrender a cord "worn or frayed." Therefore,there is no need to repair or replace such acord.OSHA STANDARDS
Stapled through cord!
AMPACITY AND WIRE INSULATION*According to the electrical code, the overcurrentprotection shall not exceed 15A for #14, 20A for#12, or 30A for #10(However, insulation is a factor inlocations above 86 F)
WIRE AND CIRCUIT BREAKERSIZING FOR MOTOR LOADS
HAZARDS and RISKSwhen working withELECTRICITY
What is the BEST WAY TOPREVENT THE HAZARDSof electricity?AVOID energizedcircuits - the safest way!
THINKbefore takingAction
THINKabout theRisks and Hazards
OPTIONSDo you have options like:LOTO (Lockout/Tagout)
PROTECTIONAre you wearing PPE?(Personal ProtectiveEquipment)
WHAT are theHAZARDS and RISKS?1.2.3.ShockArc Flash & Arc BlastFire Ignition
SHOCK AND ITS EFFECTSImmediate:1.Muscle contraction2.Vital organs 7.Dizziness8.Possible death
SHOCK AND ITS EFFECTSLong Term:1.Memory Loss2.Nervous disorders3.Chemicalimbalances4.Damage to vitalorgans5.Sometimes fatal
EFFECT OF CURRENT ON THE BODYMEN Perception ThresholdWOMEN 0.001 Amps (1 mA) Painful Shock0.0007 Amps (0.7 mA) 0.009 Amps (9 mA) Cannot Let-Go LevelVentricular Fibrillation Heart Failure Organ Burn1.5 Amps (1500 mA)Ventricular Fibrillation.100 Amps (100 mA) 0.5 Amps (500 mA) Cannot Let-Go Level0.010 Amps (10 mA).100 Amps (100 mA) Painful Shock0.006 Amps (6 mA)0.010 Amps (10 mA) Perception ThresholdHeart Failure0.5 Amps (500 mA) Organ Burn1.5 Amps (1500 mA)
TWO TYPES OFBURNS FROM SHOCKSurface Burns: Caused by entrance and exit ofelectrical currents through the body Can be caused by a very smallamount of current 1st degree to 3rd degree
ARC FLASH & BLASTRELATIVE TO THE HUMAN BODY: A 2nd degree burn threshold, or a ‘justcurable burn threshold,’ is skin temperatureraised to 175oF for 0.1 second. A 3rd degree burn threshold, or ‘incurableburn threshold,’ is skin temperature raisedto 200oF for 0.1 second. Eardrum damage 720 psf Lung damage 1728 psf
TWO TYPES OF BURNSFROM SHOCKInternal Tissue Burns: Caused by current flowingthrough organs of the body Caused by currents in excessof 1.5 amps 4th degree (internal) Internal organs Typically Fatal
PROTECTION FROMABNORMAL CONDITIONS NFPA 70E OSHA Electrical Safety ProceduresManual Electrical Safety Training
Equipment Labeling
Equipment Labeling
Questions?
EFFECT OF CURRENT ON THE BODY MEN Perception Threshold 0.001 Amps (1 mA) Painful Shock 0.009 Amps (9 mA) Cannot Let-Go Level 0.010 Amps (10 mA) Ventricular Fibrillation.100 Amps (100 mA) Heart Failure 0.5 Amps (500 mA) Organ Burn 1.5 Amps (1500 mA) WOMEN Perception Threshold 0.0007 Amps (0.7 mA)
