Solar Photovoltaic Basics, A Study Guide for the NABCEP Entry Level Exam by Sean White4324

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Safety basics
• Metal ladders conduct electricity so electrical workers should use heavier
fiberglass ladders.
Use an extension ladder to climb on a roof, not an A- frame ladder.
•
Keep 3 points of contact on a ladder. Carrying objects up a ladder in one
hand can be dangerous!
ARCING AND ARC FLASHES
Electrical voltage is the hydraulic (water) analogy of pressure and when
voltage is higher, so is the chance of a spark or an arc.
In a PV system, if there is a small gap in a circuit, then we can have an arc where
electrons will travel through the air. Many newer inverters are equipped with
arc fault detection. If there is an arc, then the inverter should shut off. An arc is
a “plasma discharge” and is a very hot fire hazard.
An arc flash is an explosion when a great amount of energy is released with
an arc. When working with larger systems and close to the potential spark/arc,
you need to have proper arc flash personal protective equipment, which is like
a space suit. Arc flashes are hotter than the sun. Often the more dangerous
source of power is the utility rather than the PV system. The utility has more
potential than our PV systems.
PPE is personal protective equipment and can include arc flash suits,
earplugs, goggles, aprons and personal fall arrest systems (PFAS). PFAS
are usually the most important types of PPE protection gear in the
solar industry.
OVERCURRENT PROTECTION DEVICES
Fuses and circuit breakers (overcurrent protection devices) are used to prevent
fires. On the backside of a PV module, there is a label that says the maximum
series fuse rating. The fuse will open the circuit (turn off) if there is too
much current in order to protect wires and equipment.
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