Steel with rubber insulated handles
All technicians, electricians, plumbers and handymen use pliers almost every day.
There are electricians straight pliers, wiring pliers, long nose pliers, angled long nose pliers, side cutting pliers, parallel jaw pliers, locking pliers, aircraft twist locking pliers, channel lock pliers, oil wrench pliers, water pump pliers and fencing pliers. -I have each of these and I'm sure there are many more kinds.
Klein is a well known provider of hand tools for electricians that are rubber insulated for shock resistance.
Pliers are made of steel. There are plastic pliers for children too.
Metal
Flat nose pliers are to hold and grip things, or to twist wires together as for electrical connections.
Contact lenses are made from plastics and electricians are usually exposed to heat. When direct heat reaches the contact lenses as the electricians wear it, Chances are; The contact lenses might melt into the eyes and you could never remove them.
Pliers are made of steel and as such will conduct heat -and electricity! However pliers whose handles are covered with rubber or plastic sleeves will be insulated against heat.
The Patron Saint of Electricians is St. Lucy
Plastic is a property of metal for electricians
Henry Miller is a famous electrician, he was the first president of the IBEW and help thousands of electricians to get safer work conditions in the late 1800's. See related link below for more info.
Long nose pliers are made out of steel.