5.2.4 Insulating Mat
1.Basic Structure and Functions of Insulating Mat
(1)Basic structure
The insulating mat shall be made of rubber insulating material,and the upper surface shall be designed with anti-slip features such as wrinkle or diamond pattern to enhance the anti-slip property of the surface.The back surface may be made of cloth or other anti-slip materials,as shown in Fig.5-24.
Fig.5-2-8 Insulating Mat
(2)Basic function
①The insulating mat is made of rubber insulation material and laid on the ground or grounded object to protect the operators from electric shock.
②It has stable withstand voltage and the functions of blocking electric arc,voltage and partial current.
2.Classification and Technical Specifications of Insulating Mat
(1)Classification
①According to the voltage grade,it can be divided into 5kV insulating rubber mat,10kV insulating rubber mat,15kV insulating blanket,20kV insulating rubber board,25kV insulating rubber board,30kV insulating rubber board and 35kV insulating rubber board.
②According to the color,it can be divided into red,dark black and green insulating rubber mats.
(2)Technical
①The insulating mat is divided into four grades:0,1,2 and 3 according to its electrical properties.
②The insulating mat shall be made by seamless manufacturing technology.
③There shall be no harmful irregularities on the upper and lower surfaces of the insulating mat.
④The diameter of the insulating mat depression shall be no more than 1.6m,and the edge is smooth.When the reverse surface of the depression is spread on the thumb,there shall be no visible mark on the front side.There are less than 5 depressions,and the distance between any two depressions shall be no more than 15mm.When it is stretched,depressions or models tend to have smooth surfaces.The bumps formed by impurities on the surface do not affect the extension of the material.(https://www.daowen.com)
3.Inspection Contents of Insulating Mat
In order to ensure the integrity of the electrical and mechanical properties of the insulating mat,its both sides shall be carefully inspected before each use.Its appearance and surface shall be flat and smooth,uniform in color,free from impurities,pinholes,cracks,cutting and other obvious defects;the surface of the insulating mat shall be clean and dry;the insulating mat shall have a test certificate within the test time limit.
4.Usage of Insulating Mat
(1)The insulating mat is only for live working of power equipment 10kV or below,as shown in Fig.5-25.
(2)The insulating mat does not play the role in main insulation,but occasional short-term contact is allowed,and it shall be used in conjunction with the human body safety protection appliances.
Fig.5-25 Use of Insulating Mat
5.Precautions for Storage of Insulating Mat
(1)The insulating mat shall be stored in a special box to avoid direct sunlight,rain and snow,and to prevent squeezing and sharp objects from colliding.
(2)It is prohibited to store it near steam pipe,heat dissipation pipe or other artificial heat source,and it shall be kept more than 1m away from the heat source.It is prohibited to store it in the environment with direct sunlight,light or other light source;no contact with oil,acid,alkali or other harmful substances is allowed.The storage ambient temperature should be between 10°C and 21°C.
(3)The damp insulating mat shall be dried,but the drying temperature shall not exceed 65°C.
6.Test contents of Insulating Mat
The test contents of the insulating mat are as follows.
(1)Mechanical test.Including mechanical puncture test and anti-slip test.
(2)Electrical test:Including AC voltage verification test and AC withstand voltage test which shall be done once every six months.
(3)Preventive testing item of the insulating mat include mark check.