alarm
alert
area
arrow
attention
background
beware
cable
caution
construction
danger
dangerous
death
electric
electrical
electricity
energy
extreme
generator
hazard
high
icon
illustration
industrial
industry
information
injury
keep
label
lightning
power
precaution
protection
radiation
restricted
restriction
risk
safety
secure
security
shock
sign
sticker
striped
symbol
transformer
voltage
warning
zone