Student safety 2011 5th edition - Pt 1 , Pg 1-5 Flashcards
https://drive.google.com/file/d/1mQ5Wk9Wum3EO2lnTtReSaqh-vwCxBy1_/view?usp=sharing
What does “energized” mean in electricity?
Pg 2
electrically connected to/have voltage source
What does “exposed” mean in electricity?
Pg 2
(applied to energized electrical conductors) can be inadvertently touched nearer than a safe distance by a person.
What does “externally operable” mean in electricity?
Pg 2
capable to be operated without exposing the operator to contact with energized electrical conductors or circuit parts
What does “in operation” mean in electricity?
Pg 2
a term to describe a lab
A lab is in operation if it meet these conditions:
- power is on in a workstation
- students are wiring/troubleshooting equipment/circuits/staff are setting up or troubleshooting equipment or circuits
What’s a safety eyewear?
Pg 2
safety glasses meeting current standards for low impact eye
protection, which must have side shields
What’s a circuit?
Pg 2
E.g. A path that can result with a turned on flashlight’s batteries has electricity flow to the lamp and back to it.
What’s the amount of electricity flowing called?
Pg 3
current
What’s the amount of electricity flowing in a circuit measured in?
Pg 3
amps
Current flows in a circuit due to the voltage supplied by what?
Pg 3
power source (battery, power supply)
If a circuit’s voltage increases the current also…?.
Pg 3
…increase
Circuits that are connected to a voltage source are
described as what?
Pg 3
alive/live
If you become part of a circuit, current gets through and you get _______.
Pg 3
If you become part of a circuit, current gets through and you get shocked.
When you become part of a circuit means you are connected it circuit in _ different places.
Pg 3
When you become part of a circuit means you are connected it circuit in 2 different places.
What’s does the “ground” refers to in electricity?
Pg 3
The “ground”
refers to the planet and any metal connected to it.
Plumbing pipes, heating ducts and metal building structures are all ________.
Pg 3
Plumbing pipes, heating ducts and metal building structures are all grounded.
Touching that’s grounded and a part of the circuit that is live to ground will result in what?
Pg 3
Touching that’s grounded and a part of the circuit that is live to ground will result in a shock.
What’s a main factor to determine a shock’s severity?
Pg 3
the amount of current
Shock currents are often measured in what?
Pg 3
in milliamps (mA)
a milliamp is ________ (1/_) of an amp?
Pg 3
a milliamp is thousand (1/1000) of an amp
What does proportional mean?
Pg 3
corresponding
True or false?
Current is not proportional to voltage
Pg 3
false
Since current is proportional to voltage, higher voltages lead to worse shocks
What’s the lowest distribution voltage that utilities use?
Pg 4
2,400-9,000 volts
Is the lowest distribution voltage that utilities use life threatening?
Pg 4
Yes, at
this voltage any direct contact is life threatening.
Pure water is a ____ conductor of electricity. Most water, including in the body, has dissolved ions that make us better conductors.
Pg 4
Pure water is a poor conductor of electricity. Most water, including in the body, has dissolved ions that make us better conductors.
True or false? Dry skin has relatively high resistance against current.
Pg 4
true
Despite a skin’s high resistance, what’s beneath can still make us a good electricity conductor?
Pg 4
Our skin’s tissue beneath is mostly water.
Even a tiny break in the skin creates a low resistance path makes a shock worse.
True or false?
It’s safe to wear metal wristband and Why?
Pg 4
false
A metal wristband makes a big contact area and makes a shock worse.
What can the skin’s initial burning and blistering lower resistance cause?
Pg 4
It cause more intense shock, burning, and blistering.
True or false? Even a tiny current through the chest affect breathing or a heart to beat.
Current through the brain can be fatal.
Pg 4
true
True or false?
Up to 1 mA we can feel a shock.
Pg 4
false
Up to 1 mA we usually can’t feel a shock.
True or false?
At ~8 mA people feel a shock without injury.
Pg 4
true
What does GFCI stand for?
Pg 4
Ground Fault Circuit
Interrupters
What’s GFCI used for and it’s opened at how much mA?
Pg 4
GFCIs can protect others in high risk areas like bathrooms, opened at 5 mA.
Currents above what mA cause burns?
Pg 5
Currents +100 mA cause burns.
Most source states 100 mA, but the Student Safety book states 10 mA.
True or false?
~10-20 mA won’t include 1st and 2nd degree burns.
Pg 5
false
~10-20 mA include 1st and 2nd degree burns.
What can above 10-20 mA cause to the body?
Pg 5
What can above 10-20 mA cause to the body?
Why can’t we let go of what’s electrocuting us?
Pg 5
loss of muscle control
A shock’s current may cause muscle to contract and “freeze”, one cannot let go even at will.
What’s the max current an average person can grasp and “let go”
Pg 5
Average people can grasp and “let go” at a max of 16 mA.
https://www.ccohs.ca/oshanswers/safety_haz/welding/electric.html#section-2-hdr
What can 20 mA do to muscles?
Pg 5
20 mA may cause muscles for breathing to be paralysed.
What happens to a body at 100 mA?
Pg 5
At 100 mA ventricular fibrillation occurs–heart stops pumping.
What happens to a body at 200 mA?
Pg 5
Over 200 mA the heart muscles clamp. There is damage to internal organs.
Smallest circuit breaker or fuse used to protect power circuits in buildings of how much amps and did they offer protection against shocks?
Pg 5
Smallest circuit breaker or fuse used to protect power circuits in 15 amps buildings, but offer no protection against shocks.
