7.2.3 Wire pliers
1.Structure and Function of Wire Pliers
Wire pliers,commonly known as calipers and hand pliers,also known as electrical pliers,are one of the safety appliances used in live working of power transmission and distribution lines.It is a tool for clamp and shearing,the structure of which is shown in Fig.7-23 and consists of a clamp head and a clamp handle.The clamp head has four openings:jaw,tooth edge,knife edge and chopping edge;the clamp handle is provided with an insulating sleeve.Fig.7-24 shows the picture of wire pliers.
Fig.7-23 Structure of Wire Plier
Fig.7-24 Picture of Wire Clamp
2.Technical Specifications of Wire Pliers
There are 150mm,175mm and 200mm specifications for common wire pliers.The insulated handle of common wire pliers has a withstand voltage of 500V,and the working voltage of high-voltage insulated wire pliers can reach 1000V.Fig.7-25 shows a picture of 1000V high voltage insulated wire pliers.
Fig.7-25 1000V HV Insulated Wire Pliers
3.Inspection Before Use of Wire Pliers
(1)Before using the wire pliers,check whether the insulating sleeve of the insulating handle is worn and cracked,so as to prevent the pliers head from contacting the charged part during work and causing accidents due to electrification of the pliers handle.(https://www.daowen.com)
(2)Before use,pull the handle to check whether the jaws of the wire pliers are flexible and reliable.
4.Usage of Wire Pliers
(1)When using the wire pliers,the knife edge of the clamp head shall face inward,that is to say,towards itself,so as to control the position of the jaw conveniently;extend your little finger between the shanks to hold the shanks and open the clamp head.
(2)During use,pay attention not to using the knife edge to cut the wire,so as to avoid knife edge damage.The cutting edge of insulated handle wire pliers can be used to cut electric wires and iron wires.When cutting No.8 galvanized iron wire,the blade shall be used to cut back and forth around the surface a few times,and then the iron wire shall be broken with only a slight pull.
When cutting live wires with electrical wire pliers,the jaws shall not be used to cut the phase line and the zero line at the same time,or cut both phase lines at the same time,which will cause short circuit of the lines.
(3)The plier head cannot replace the hammer as a beating tool.
(4)Do not throw,smash or straighten the steel wire with the handle during the use of insulated handle wire cutters,so as not to damage the insulated plastic pipe.
(5)When winding the anchor cable with insulated handle wire pliers,clamp the wire with the teeth of the pliers and wind it clockwise.
5.Precautions for Storage of Wire Pliers
The wire pliers shall be kept in a dry and well-ventilated tools and instruments warehouse,stored in a special tools and instruments box or placed at the fixed point of the shelf.
6.Preventive Test of Wire Pliers
Preventive test for HV insulating wire pliers includes appearance inspection and high-voltage power frequency withstand voltage test for insulation part.The test cycle shall be 1 year.