Safety Overview Flashcards
Most Electricians (do not) work with electricity
CAT IV (four) = Best
Bigger distance, need shorter probe
Safety
Test known circuit before unknown.
What makes a circuit dangerous?
-amount of volts
-amount of current (most crucial)
-condition of skin
-path it takes through our body
-AC or DC (AC more dangerous)
Occupational Health and Safety (OSHA)
-provincial not federal
-Employer responsible for providing safe environment
-employee identify what’s not in compliance
methane - poop and rots (come from)
use for generators (methane)
Confined space
Why Confine space is dangerous?
-heat (outside)
-lack of oxygen (biggest)
-inhale chemical fumes
Safety measures?
-there must be guy outside (guard) - must never enter (confine space)
-lash (roper) to other guy (harness)
-permit (trained) - may need burning permit
Lockout & Tagout Procedures
Purpose?
-prevent energizing equipment (or by other people - by mistake)
-switches
-circuit breakers
-valves (block)
-lock with padlock (your own) - keep key to urself
6, 11, 16 class
Safety Harness (need 6 foot rope (lanyard)
For what?
-when above 6 feet
-near hole or drop off
-high scaffolding
*manlift
Ladder and Scaffold
4:1 out of 4 out 1 or 75 (76) degrees
Ladders
-made of fibre glass or aluminium (conductive though) combination fibreglass
-don’t really use wood anymore (heavy when wet - Slippery)
-need extra 3 feet on top
20 foot long (height) & 5 feet away (4:1) (from the base)
Never step on top of ladder (also 2 steps down)
Different types of fires
AFCI (arc fault circuit interruptor)
GFCI (ground fault circuit interruptor)
Types of scaffolds:
-Rolling Scaffolds
-Hanging or Suspended Scaffolds
Safety harness:
-upper body with leg, shoulder, & chest straps & (secured above the worker)
Fires
Different materials require different amounts of heat for combustion take place.
Oxygen - if fire is denied oxygen, it will extinguish
-oxygen must be present for combustion to take place
Fire are divided into four classes: A,B,C, and D
Class A - common combustible materials - wood and paper
.
-used (often) water to extinguish fire by lowering temperature of fuel
Fire are divided into four classes: A,B,C, and D
Class B - involves fuels - grease, combustible liquids or gases
-employ (generally) carbon dioxide (CO2) to greatly lower temperature of fuel & deprive oxygen
-use for electrical fires (do not coat it with dry powder - destroy surrounding equipment)
Fire are divided into four classes: A,B,C, and D
Class C - involves energized electrical equipment
-use (usually) dry powder to smoother the fire
Many fire extinguishers used on multiple types of fires
-an extinguisher labelled ABC could be used on any of the three classes of fire
Never use an extinguisher not rated. - using class A extinguisher water on electrical fire can be fatal
Fire are divided into four classes: A,B,C, and D
Class D - consist of burning metal. - water can increase fire
-uses a powder placed on top of the burning metal, forms a crust to cut off the oxygen supply terminal.
-some powders only stop the fire from spreading to other combustible materials
Greatest cause of electrical fires - poor or loose connections
-creates resistance, resistance causes heat
Fires
Electricity is a form of pure energy
- the electrical unit (watt) - measures the amount electrical energy converted into some other forms
When resistance is present electrical energy is converted into thermal energy or heat
-soldering irons - range from 15 to 30 watts
The higher the current (higher current load), the more a small resistance increase can cause extreme amount of heat
P = I power of 2 x R
P = 25 x 25 x 0.25
P 156.25 Watts
Poor connection can cause the metals of the conductor & terminal to oxidize & develop even more resistance (more damage) (melt & burn away conductor connected to terminal)
Glove Safety
-test gloves once a year (rubber or leather gloves)
-don’t lend rubber or leather gloves (safety)
-1000 volts?
-12,000 volts (bigger gloves)(line workers) (BC Hydro) (Industrial)
-balloon test (test for rips) (Lab test)
-chemical break (use respirator) ( last only 3 - 5 minutes)
Lockout & Tagout
-box padlock (cords or plugs)
-circuit breaker padlock (two kinds: screw & chip)
-large motor switch padlock
-switch cover (padlock)
Tag
-remember name, date (& time), and phone number
Horseplay
-pushing
-throwing
-doing dangerous stuff near people
2 mA - .002 - slight tingling
(50 mA) 40 mA - 200 mA - dangerous
100 - 200 mA (fibrillation)
Ground fault circuit interuptor
-bathroom GFCI protected
-curling iron
-outdoor construction
-lawnmower (wet)
-trip one cycle
GFCI - must trip at 4 - 6 mA (or 5 mA)
-difference of 5 mA shut circuit down (opens circuit)
GFCI - swimming pools
-hot tubs
-protect life (electrocution)
-trips one cycle
GFCI devices
-two buttons
-green indicator light
-circuit breaker style
-plug style (cheaper) - protects anything below besides receptacle
Ground fault extension (multi outlet)
Arc-Fault circuit interruptor (AFCI’s)
-protected people (fire)
-sparks cause flames
-use all 120v, single phase, 15-20 A circuit
*National
Used faulty rooms, dining rooms, living rooms, dens, bedrooms, laundry rooms, recreation rooms, hallways, or similar rooms or areas
except kitchen & lighting
Expensive, AFCI looks like GFCI plug style
-can protect everything below
-but need installation for everything ($)
Series arc fault - a loose screw or wire connection damaged
arc fault - funny waveforms
Normal switch turning on (spike for first wave form)
Need u-ground to push through plug - Tamper - resistant receptacle mainly close to ground or kitchen
Ground triggers break by - imbalanced neutral
Identify Energy Sources:
Electrical
Mechanical (moving parts)
Pressure (gas, liquids)
Thermal (open, flame)
Stored energy
Hazardous
Each person have own lock & key
never share
wedges - secondary isolation
Notify effected employees
-(clear of personnel, check everything is guarded)
-restart
Scaffolds - safest elevated working platform to do electrical work
-adjustable feet on bottom sections to level the sections
-has two end sections are connected by X braces that form a rigid platform
-sections of scaffolding are stacked on top of each other to reach desired height
Two types of Scaffolds - Rolling & Hanging or Suspended Scaffolds
Rolling scaffolds - used inside buildings - in areas that contain level floors
-equipped with wheels on the bottom section to permit moving it from one position to another
-the wheels have a mechanism that locks them after the scaffold is rolled to desired location
Two types of Scaffolds - Rolling & Hanging or Suspended Scaffolds
Hanging or Suspended scaffolds - suspended by cables from support structure
-used on the side of buildings to raise & lower workers by using hand cranks or electric motors
X braces connect scaffolding sections together
Ladder - two types straight & step ladders
-should check it’s load capacity regardless of the type of ladder used (found on side of ladder)
Common load capacities are:
91 kg (200 lbs)
113 kg (250 lbs)
136 kg (300 lbs)
do not use a ladder that does not have enough load capacity to support your weight plus the weight of your tools & the weight any object your taking up the ladder with you.
straight ladders - constructed by placing rungs between two parallel rails
-safety feet on one end that prevents ladder from slipping
Step ladders - self - supported, constructed of two sections hinged at the top
-the front section has two rails & steps, the rear portion two rails & braces
do not use top ladder (unbalanced & falling)
Parts of step ladder
Ladder top, spreader, top step, and highest usable step
Fires
fire need 3 things to burn - fuel, heat, & oxygen
Fuel - is anything that can burn - wood, paper, cloth, combustible dusts, & even some metals
Combustion temperature - if a fuel is below it’s combustion temperature it will not burn
