alert
arrow
attention
background
black
blue
board
careful
caution
charge
close up
closeup
conductors
current
danger
dangerous
detail
distribution
electric
electrical
electricity
energy
fence
hazard
hazardous
high
industry
metal
metallic
notice
power
powerline
powerplant
precaution
protection
risk
safety
sign
signal
single
sky
supply
symbol
technology
tension
triangle
voltage
warning
white
yellow