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Electrical Safety

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Welcome to the Airefco service group
YouTube channel. Please remember to subscribe and ring that bell to get
notified whenever we upload a new video. Electricity will only travel in a
completed circuit. When you flip the light switch off you are breaking the
circuit. When you turn the light back on you complete the circuit by flipping the
switch on. That’s called a closed circuit.
Electricity always travels in the path of least resistance. Every electrical
device has a certain amount of electrical resistance. Circuit breakers
were developed to break the circuit and stop the flow of electricity if the
source of resistance were bypassed to prevent the circuit from overheating.
Electricity always travels to ground>Electricity will travel through a person
because most often, that person offers less resistance than the electrical
device. If the person is touching ground, that person will form a completed
electrical circuit. Now the electricity will prefer to travel through the person
because you offer less resistance and then on to ground. Electricity always travels to ground. The effects of electricity on the human body
doesn’t take much electricity to hurt you. Even one milliamp can be felt by the
human body. Two to ten milliamps can result in a minor shock. At ten to twenty
five milliamps the person may lose muscle control and may not be able to
release or let go of the circuit. This situation is especially dangerous if
there are no other people in the area who can break the circuit by removing
the person from the equipment. A 25 to 75 milliamp shock is painful and may lead
to collapse or even death. The longer the person is exposed to this electrical
current the more likely death will occur. 75 to 300 miliamp for even a quarter of
a second is almost always fatal. Even the seemingly low voltage of 120 volts can
be extreme hazardous to a person. You can receive a
shock around 60 milliamps because the skin offers the most of the body’s
electrical resistance the point of electrical contact with the skin will
determine the amount of shock received. Remember, the higher the resistance the
less milliamps of exposure which means lower amount of shock. Resistance is
increased if you are shocked in an area that has thick or callous skin such as
the palms of your hands, your fingers or the soles of your feet. Your resistance
decreases thus increasing your shock if the electricity contacts you in an area
of thin skin, if your skin is wet or sweaty, or if the skin is broken such as
where you have a cut or a bruise or an abrasion on your skin. Because
every human body is built differently every one of us will have a different
level of resistance. The range can be from as little as 500 ohms to many
thousands ohms. As we’ve already discussed, the greater your body’s
resistance the less amps you will receive and thus the less chance you
will be harmed by the shock. This is why similar voltage shock can feel minor to
one person and deadly to another. Of course there are other considerations a person may have a bad heart which would make them more sensitive to the shock.
The primary way to protect yourself from electrical hazard is by using personal
protection equipment that increases the resistance offered by the body thus
decreasing the amount of shock you’re exposed to. Of course you want to
make sure that the personal protection equipment used is properly rated for the
voltage that you might be exposed to. Gloves provide increased resistance at
the most likely point of electrical contact. Shoes and mats increase
resistance by making it more difficult for the current to reach ground.
Electrical systems when designed and built properly are the safest form of
energy. Injuries typically occur when improper procedures are used, the hazards of electrical systems are not understood, or not taken seriously or when safety
systems are ignored or circumvented. This is why it is so important for workers to
identify and understand hazards of electricity. Inspect equipment
before they use it and use the equipment correctly always stay at least 10 feet
away from high-voltage power lines. High-voltage lines are bare conductors
so contacting them with a ladder, cherry-picker, a man lift, bucket truck,
etc, can cause an electrical shock. If a dump truck were to touch high-voltage
lines when it raised its bed to unload its contents, the driver would not even
feel the electricity because the large rubber tires would prevent the voltage
from reaching ground. However, if the driver were to step out of the truck, he
would be electrocuted as soon as his foot touched the ground. Damaged wire
insulation exposes hot wires to potentially combustible materials and
may start a fire. Always contact your local utility company prior to doing any
digging or trenching and have them mark the locations of any wires or
underground utilities. Broken switches or plugs can cause overheating in a circuit.
Overloaded circuits are created when too much electrical current is running
through a given electrical system. Appliances or tools can become
overheated if they have an internal electrical problem. Static electricity
can cause discomfort for workers or even start a fire or explosion when around
flammable materials. Make sure flammable materials are properly stored and
grounded especially when chemicals are being dispensed. Almost all electrical
equipment is designed with some sort of grounding systems so that if there is a
problem such as a short-circuit the electrical current will go to through
the grounding system rather than through the human body.
Do not use equipment with damaged grounding connectors. Do not use an
adapter that converts a three-prong system into a two-prong system. Again
this interrupts the grounding connection. These adapters were not designed to send the ground current back to ground if there is a problem. GFCI receptacles are
found in many locations but primarily in the restroom areas where an electrical
appliance could fall into a sink full of water. if this occurs the GFCI would automatically shut off the power to the
receptacle. The receptacle then has to be manually reset. GFCIs can also be
portable and used with extension cords and power tools. Fuses and circuit
breakers operate at several amps to allow the circuit to continue even when
slightly overloaded. Remember people are injured at the milliamp level. Flammable
and ignitable materials include flammable gases, vapors or liquids and
combustible dust. All of these can be ignited by even the smallest spark of
electricity. People have been killed and seriously injured by the ignition of a
flammable substance by static electricity. For example when filling
portable gasoline containers at the gas station. Place the container on the
ground before filling it. This will allow the container to be grounded.
These containers have been known to explode from static electricity when
left in a truck bed. The plastic container rubs on the plastic truck
liner and causing a static electricity and then when you touch it it can set
off a spark. Rooms that permanently user store flammable substances require
special explosion proof electrical systems with their lighting and outlets.
Do not use portable power equipment in rooms that are known to intermittently
contain flammable substances. Mos people assume that the white wire in a circuit has no electricity flowing through it. But here we see a circuit where we have
a hundred and twenty volts and a motor. That motor is drawing seven amps. The
black wire brings the power to the motor and the white wire returns it back to
the circuit panel. If you’re working on that circuit and you come across the
white wire you might assume that it has no power flowing through it. But it could
it could have seven amps coming from that motor which would then flow through
you to the ground seven amps will kill you. A white or neutral wire can actually
be more dangerous especially if there’s a load on the circuit than the black wire. You may not open a service panel unless you hold an O1
electricians license or are under the direct supervision of one.

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