alert
arrow
beware
black
cable
catenary
caution
contact
danger
dangerous
electric
electrical
electricity
electrified
energy
flash
frame
hazard
high
industrial
industry
information
infrastructure
lightning
line
mast
metal
network
overhead
power
powerline
rail
railroad
railway
safety
security
shock
supply
symbol
technology
transportation
uk
volt
voltage
warn
wire
wiring