Module 12 Electrical Safety and material safety

Contents

Electrical Safety and materials safety

This week we are covering two topics electrical safety and materials safety. This is because when there is an electrical accident heat is produced. You need the knowledge of the safety rating of the materials your clothing and PPE are made out of. The clothing and PPE should be rated as flame resistant or flame retardant. These materials are protective against heat is necessary to keep your and your team safe. Be sure you know the difference and ratings before you distribute the PPE and train your team.

Video Electrical Safety

Lock out Tag out Video

Transcript 12 Video Electrical Safety

Welcome Health and Safety to the Electrical safety lecture

Electrical current exposes workers to a serious, widespread occupational hazard; practically all members of the workforce are exposed to electrical energy during the performance of their daily duties, and electrocutions occur to workers in various job categories. Many workers are unaware of the potential electrical hazards present in their work environment, which makes them more vulnerable to the danger of electrocution.

Slide 2

Electrical hazards can be anywhere in the work space. Shock, burns, arc-blasts explosion and fires can be the negative result of an electrical disaster.

http://www.cdc.gov/niosh/topics/electrical/

Slide 3

So how an we keep workers safe from electricity. Make sure all cables have their proper insulation. Main electrical protective devices. Use proper guarding. BE sure gear is grounded. And wear the proper personnel protective equipment.

Slide 4 insulation

Lets talk about insulation. Wiring insulation is made out of Glass, mica, rubber, plastic inspected cables before using or turning on system.

Slide 5 Fuse

The simplest circuit protection device is the fuse. A fuse is just a thin wire, enclosed in a casing, that plugs into the circuit. When a circuit is closed, all charge flows through the fuse wire — the fuse experiences the same current as any other point along the circuit path. The fuse is designed to disintegrate when it heats up above a certain level — if the current climbs too high, it burns up the wire. Destroying the fuse opens the circuit before the excess current can damage the building wiring.

The short fall with fuses is they only work once. Every time you blow a fuse, you have to replace it with a new one. A circuit breaker does the same thing as a fuse — it opens a circuit as soon as current climbs to unsafe levels — but you can use it over and over again.

Circuit breakers

The circuit breaker’s job is to cut off the circuit whenever the current jumps above a safe level. The circuit breaker trips whenever it detects too much current in the circuit. The breaker heats up or detects a larger magnetic field and shuts off. Circuit breakers are designed to protect your building not the occupants.

But there is a breaker designed specifically to protect human beings.

¡ GFCI-ground fault circuit interrupter

The device is the ground fault circuit interrupter, or GFCI. These sophisticated breakers are designed to protect people from electrical shock, rather than prevent damage to a building’s wiring. The GFCI constantly monitors the current in a circuit’s neutral wire and hot wire. When everything is working correctly, the current in both wires should be exactly the same. As soon as the hot wire connects directly to ground (if somebody accidentally touches the hot wire, for example), the current level surges in the hot wire, but not in the neutral wire. The GFCI breaks the circuit as soon as this happens, preventing electrocution. Since it doesn’t have to wait for current to climb to unsafe levels, the GFCI reacts much more quickly than a conventional breaker.

https://www.pioneerbreaker.com/v/vspfiles/V4_Backup/Tools/howCircuitBreakersWork.htm

Slide 6 Types of electrical failures

OVERLOAD- Plugging to many current drawing devices into one circuit.

FAULT-current flows through an abnormal or unintended path. The may be a result in the failure of insulation or a fault in the installation. This can be between either the live and neutral conductors, or the live and earth.

SHORT CIRCUIT- accidental contact between two points in an electric circuit Such as hot and neutral. When a short occurs, a large current flow through a fuse or circuit breaker will open the circuit, blowing the fuse or tripping the breaker.

GROUND FAULT- a ground fault occurs when the “hot” wire comes into contact with a grounded portion of the electrical system such as a junction box or grounded part of an appliance or device. Similar to a short circuit, large amounts of current are forced to flow through the fuse or circuit breaker, causing a fuse to blow or a circuit breaker to trip.

Slide 7 Example of short in an electrical box

As for short circuits and ground faults, we don’t want either, but with the use of protective devices like fuses and circuit breakers, we can rest easy knowing that we have electrical safety devices guarding us at all times. Electrical shorts and ground faults can be caused by working on a circuit that wasn’t turned off first, or damage to the insulation causing contact with the electrical box.

Slide 8 Guarding

How do we guard against problems? To guard against an electrical accident respect Enclosures. That are locked. Install electrical systems Elevated and away from easy access. The idea is to keep access limited to the panels before an accident can occur. Some panels will not open unless the electricity is shut off. Other enclosures are elevated away from easy access.

Slide 9

Grounding

Grounding is a method of giving electricity the most effect way to return to the service panel. The current flows from the panel to the outlet or device to power up your tools. The neutral wire is the return path for unused current. The ground wire is an additional path for electrical current to return safely to ground without danger to anyone in the event of a short circuit. In that instant, the short would cause the current to flow through the ground wire, causing a fuse to blow or a circuit breaker to trip.

Slide 10

Wear the correct personnel protection equipment for the job.

Slide 11

Use lock out tag out procedures before working on any electrically supplied tools.

Slide 12 Lock out Tag Out

The process of preventing the flow of energy from a power source to a piece of equipment. Placing a tag on the power source; warning not to restore the energy. This is not a physical restraint. Tag must clearly state “DO NOT OPERATE”.

I have included a video in this module for you to observe a basic lock out tag out system

Slide 13

To keep yourself safe around electrical equipment, Maintain all electrical equipment. Use safe features such as ground cables. Install or repair only if you are trained and qualified. Keep equipment neat and clean. Never install electrical devices or use near water.

Good luck health and safety

Bibliography

https://www.osha.gov/OshDoc/data_Hurricane_Facts/elect_safety.pdf

http://www.cdc.gov/niosh/topics/electrical/

lock out tag out video: https://youtu.be/VhKKkRmhRGI