advice
alert
attention
black
board
caution
close
danger
dangerous
death
detail
electric
electrical
electricity
energy
fence
forbidden
hazard
high
icon
industrial
industry
information
line
mesh
metal
metallic
notice
power
powerlines
precaution
protect
protection
protective
risk
safety
security
sign
station
symbol
technology
triangle
up
voltage
warning
wire
yellow