5.1.1 Insulating Gloves for Live Working
1.Basic Structure and Function of Insulating Gloves for Live Working
(1)Basic structure
①The gloves are made of synthetic rubber and the gloves can be lined to prevent chemical corrosion and reduce the aging effects of ozone on the gloves.
②According to the structure,the gloves can be divided into the baseline of the thumb,the wrist,the flat cuff,the curling cuff,and the midpoint height of the middle finger.
(2)Basic function
The insulating gloves for live working are gloves that are electrically assisted and insulating during live working on high-voltage electrical equipment or devices,which are made of synthetic rubber or natural rubber and are mainly used for insulation protection of the hands of live workers.At present,the maximum insulation level is up to 2,that is,the gloves can be used at 10kV or below.
2.Classification and Technical Specifications of Insulating Gloves for Live Working
(1)Classification
①According to the usage,the gloves can be divided into conventional insulating gloves and composite insulating gloves.This chapter focuses on conventional insulating gloves,shown as Fig.5-1.
Fig.5-1 Conventional Insulating Gloves
1-baseline of thumb;2-wrist;3-flat cuff;4-curling cuff;5-midpoint height of the middle finger
②According to the shape,the gloves can be divided into single insulating gloves,mitten insulating gloves,long-sleeved composite insulating gloves and arc-shaped cuff insulating gloves.
③According to the electrical performance,the gloves can be divided into five grades:0,1,2,3 and 4.Gloves with different nominal voltages are shown in Table 5-1.
Table 5-1 Gloves with Different Nominal Voltages
Note:ACa refers to line voltage in a three-phase system.
④Gloves with special properties are divided into 5 types:A,H,Z,R and C5,shown in Table 5-2.
Table 5-2 Gloves with Special Properties
Note:Class R has the property of A,H and Z.
(2)Technical parameters for conventional insulating gloves
①Length of conventional insulating gloves.The length of conventional insulting gloves of different grades is shown in Table 5-3.
Table 5-3 Length of Conventional Insulting Gloves of Different Grades
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②Thickness of conventional insulating gloves.In order to maintain proper flexibility,the maximum thickness of the glove plane(when the surface is not ribbed)is divided into five levels:0,1,2,3,and 4,and the thicknesses are 1.00mm,1.50mm,2.30mm,2.90mm,and 3.60mm.
3.Inspection Content of Conventional Insulating Gloves
Before use,the conventional insulating gloves must be inspected,including the following:
(1)Identify no harmful and tangible surface defects by inspecting the inner and outer surfaces of the gloves.
(2)Where one of the gloves may not be safe,the gloves cannot be used and should be returned for test.
(3)Before use,air leak test shall be carried out:first,insulate the insulating gloves and squeeze them on the face to check for air leaks.The air leak test is shown in Fig.5-2.
Fig.5-2 Air Leak Test of Insulting Gloves
4.Usage of Conventional Insulating Gloves
(1)When using,mechanical protective gloves(such as sheepskin gloves)should be used on the outermost layer of the insulating gloves.The use of insulating gloves is shown in Fig.5-3.
Fig.5-3 Usage Example of Insulating Gloves
(2)Avoid using the insulating gloves to directly press a sharp object.
5.Precautions for Storage of Conventional Insulating Gloves
(1)Insulating gloves shall be packaged in separate parts.The gloves shall be stored in a special box to avoid direct sunlight or stored near artificial heat sources,to prevent rain and snow from immersing,and prevent extrusion and sharp objects from colliding,otherwise the gloves may be punctured or scratched.
(2)It is prohibited to contact the gloves with oil,acid,alkali or other harmful substances,and it shall be kept more than 1m away from the heat source.The storage environment temperature should be 10-21°C.
(3)In case that the gloves are dirty,it is necessary to wash with soap and water,and apply talcum powder after thorough drying.In case that a mixture of tar and paint adheres to the gloves,it is necessary to wipe it off with suitable solvent.
6.Test for Conventional Insulating Gloves
The conventional test contents of conventional insulating gloves are as follows.
(1)Appearance inspection includes visual inspection,dimensional inspection,thickness inspection,process and molding inspection,marking inspection,and packaging inspection.
(2)Mechanical test includes tensile strength and elongation at break test,tensile permanent deformation test,mechanical puncture test,abrasion test,cut resistance test,and tear resistance test.
(3)Electrical test includes AC verification tests,AC withstand tests,DC verification tests,and DC voltage tests.
(4)The electrical test cycle:the preventive test is conducted once every six months,the inspection test is once a year,and the interval between the two tests is half a year.The test of insulating gloves is shown in Fig.5-4.
Fig.5-4 Test for Insulating Gloves