electrical safety

A comprehensive set of practice flashcards covering electrical safety hazards, risk control hierarchy, arc flash and shock boundaries, PPE requirements, and lockout/tagout procedures as described in the lecture notes.

What are the two main electrical hazards identified in the module?

Arc flash and Electrical shock.

According to the hierarchy of risk control methods, which method is considered the safest?

Elimination (de-energizing conductors and circuit parts).

What Canadian standard addresses electrical safety requirements for workers and serves as the primary reference for this training?

CSA Z462: Workplace Electrical Safety Standard.

What represents the 'first line of defence' against personal injury on a construction site?

Awareness of the hazards.

Which legal bodies establish and enforce the identification and mitigation of jobsite hazards in Alberta?

The Occupational Health and Safety (OHS) Code and the Occupational Health and Safety Act.

What is the definition of an arcing fault?

An electrical current that passes through the air.

During an arc flash incident, temperatures can reach upwards of what value?

$$20\,000\,^{\circ}\text{C}$$

What is the maximum noise level a sound blast can reach during an arc flash incident?

$$165\,\text{dB}$$

What are the three main factors that determine the severity of an arc flash injury?

The working distance from the fault, the amount of abnormal arcing fault current, and the time it takes for the upstream protective device to open.

How is Incident Energy measured?

In joules per centimetre squared ($\text{J/cm}^2$) or calories per centimetre squared ($\text{cal/cm}^2$).

What is the specific incident energy level used to define the Arc Flash Boundary?

$$1.2\,\text{cal/cm}^2$$

What type of burn is associated with exposure to $1.2\,\text{cal/cm}^2$ of incident energy on unprotected skin?

A second-degree burn.

According to the notes, what is the average resistance of dry skin?

$100\,000\,\Omega$ to $600\,000\,\Omega$

Which current level range is associated with 'ventricular fibrillation' of the heart, which is often fatal?

$$100\text{--}200\,\text{mA}$$

What current level range results in the loss of muscular control where an individual 'cannot let go'?

$$15\text{--}20\,\text{mA}$$

What term refers to the long-term symptoms (psychological, neurological, or physical) resulting from electrical injury?

Sequelae

What are the two types of shock protection approach boundaries?

The limited approach boundary and the restricted approach boundary.

For a $120\,\text{V}$ system, what is the limited approach boundary distance?

$3\,\text{ft}\,6\,\text{in.}$ ($1.0\,\text{m}$)

When working near overhead power lines, what distance must be maintained until the voltage is verified?

$23\,\text{ft}$ ($7\,\text{m}$)

What are the five emergency action steps to take in the event of an electrical shock accident?

1. Safely remove the victim from the source of shock; 2. Prevent further injury; 3. Send for qualified help; 4. Eliminate the danger; 5. Report the accident.

According to Part 18 of the OHS Code, who is legally obligated to ensure correct PPE use?

Both the employer and the worker.

What does the abbreviation ATPV stand for in relation to arc-rated clothing?

Arc thermal performance value.

What is the definition of the breakopen threshold energy (EBT)?

The incident energy on a material that results in a $50\,\%$ probability of a hole forming with an area of $16\,\text{mm}^2$ or an opening of $25\,\text{mm}$.

Which classification of eye protection covers Spectacles under CSA Z94.3?

Class 1

According to the notes, what is the primary radiation hazard during an arc flash incident?

Infrared radiation.

What symbol on a white rectangle indicates that footwear is rated for shock protection?

An orange ohm symbol ($\Omega$).

Based on the transcript, to what voltage must shock-resistant footwear be manufactured to withstand for 1 minute?

$$18\,000\,\text{kV}$$

What is the maximum voltage rating for a Class 0 (Red) rubber insulating glove?

$$1.0\,\text{kV}$$

How often does CSA Z462 require rubber insulating gloves to be professionally tested?

Every six months.

What is the required daily inspection for rubber insulating gloves before use?

An air test (inflating the gloves to identify holes).

What are the six steps involved in disconnecting and locking out power?

1. Warn personnel; 2. Use proper shutdown procedures; 3. Disconnect equipment from the supply; 4. Padlock and tag equipment; 5. Confirm (test for absence of voltage); 6. Re-energize.

What specific tool or device allows multiple workers to apply individual locks to a single piece of equipment?

A lockout hasp.