alarm
alert
arrow
attention
background
battery
beware
black
bolt
caution
danger
dangerous
death
electric
electrical
electricity
electro
electroshock
energy
flash
generator
hazard
high
icon
illustration
industrial
isolated
label
light
lightning
outage
power
problem
risk
safety
security
shock
sign
sticker
symbol
system
thunder
triangle
triangular
volt
voltage
warning
yellow
zone