There are four main types of electrical injuries:
Direct injuries, such as burns, electric shock, or electrocution
Secondary electrical injuries, such as falls due to electrical shock
Concussions
Eye damage
The seriousness of an electrical injury depends on the current flow path
through the body, the amount, current, and duration of the electrical current
exposure. Low voltage does not mean low hazard! Shock-related injuries such as
electrical burns are widespread. Touching electrical wiring or equipment that is
not properly used or maintained is the main cause of electrical burns. They typi-
cally are to the hands, arms, or legs. They can be very serious and need immediate
first aid.
Electric shock is another injury that occurs during PV
installations. Electric shock usually occurs with direct current.
DC can continue to arc even as the conductors are separated.
It allows the human conductor (an arm, leg, or any portion of
the skin) to continue to experience the effects of electricity.
Use barriers and guards to stop electrical current. Two
safety methods used to prevent electrical shocks and burns
from live circuits are lockout and tagging.
Lockout opens the circuit by locking down the alternating
current (AC) or DC power source disconnect with
a padlock.
Tagging labels the deactivated controls, equipment, and
circuits at all points where they can be energized.
Protection from Falls
The primary cause of death in the construction industry is a
fatal fall. Working on PV systems involves climbing ladders or
scaffolds, or working on rooftops. Recognizing and mastering
OSHA fall protection regulations is imperative for all
PV installers.
OSHA requires fall protection for any situation where an
employee can fall six feet or more. Fall protection is vital for
work on roofs. It is necessary for walkways and ramps. Fall
protection also is essential for work around holes and
excavations.
Employers must provide training that empowers employees
to recognize and minimize fall hazards. Training is required on
NOTE
Currents above 10 mA can paralyze or
freeze muscles.
NOTE
Workers should treat every circuit as a
hot circuit.
NOTE
Rapid heartbeats can occur when
electrical current is greater than a 75 mA
flow through the body. The current flow
can result in death in minutes unless a
defibrillator is used. Small power drills
use 30 times as many mA!
TECH TIPS
Use three-wire flexible grounded
extension cords on construction
projects. They are designed for tough
use in a work environment.
26 ADVANCED PHOTOVOLTAIC INSTALLATIONS
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