alert
arrow
attention
background
beware
caution
closed
closeup
color
danger
dangerous
death
door
electric
electrical
electricity
energy
entrance
hazard
high
illustration
industrial
industry
information
life
lock
metal
power
prevent
protection
restricted
risk
safety
security
shock
sign
station
substation
surge
symbol
technology
thunder
transformer
triangle
voltage
volts
warn
warning
wired
yellow