I.Overview
35kV large-cross-section power cables and power cables of 66kV,110kV,and higher voltage levels are all single-core cables.With the increase in electricity load and the development of urban power grids,single-core cables are being widely adopted.The use of cable sheath protectors to ensure the safe operation of single-core cables is also becoming increasingly common.
To better meet market demands and facilitate on-site installation and use of cable sheath protectors,our company has developed cable grounding boxes,which include direct grounding boxes,protective grounding boxes,and cross-bonding protective grounding boxes.The grounding box housing is made of high-quality 304 stainless steel,offering strong corrosion resistance.Additionally,the design features waterproof sealing,allowing flexible installation in cable trenches,outdoor towers,or on walls.The installation is safe,simple,and aesthetically pleasing.Currently,our series of grounding box products have been widely used across various power systems nationwide,achieving excellent operational experience.
II.Product Purpose
The device is connected between the cable sheath and the ground.
Cable sheath direct grounding box,containing internal connecting copper bars,copper terminals,etc.,used for direct grounding of cable sheaths.
The cable sheath protection grounding box and cable sheath cross-bonding grounding box contain components such as cable sheath protectors,connecting copper bars,and copper terminals,which are used for the protection and cross-bonding grounding of cable sheaths.
圖三：接地箱接線原理圖
III.Product Model Description
Cable Sheath Grounding Box
Cable grounding box categories:ZJJD-Cable sheath direct grounding box%%BHJD-Cable sheath protective grounding box%%JHJD-Cable sheath cross-interconnected protective grounding box%%IV.Usage Conditions%%1.Ambient temperature range:-45℃to+55℃;
2.Altitude not exceeding 2000m;can be customized according to actual conditions if exceeding 2000m;
JHJD-Cable Sheath Cross-bonding Protective Grounding Box
IV.Operating Conditions
1.Ambient temperature range:-45℃to+55℃;
2.Altitude not exceeding 2000m;can be customized for altitudes beyond 2000m based on actual conditions;
4.The long-term applied power frequency voltage must not exceed the protector's continuous operating voltage;for products with gaps,the temporary power frequency voltage rise at the installation point must not exceed the protector's rated voltage.
5.For prolonged use under abnormal conditions,the protector needs to be specially manufactured.Please specify when placing an order.
V.Outline and Installation Dimensions
VI.Usage Instructions
The grounding box adopts a fully sealed design,with minimal environmental requirements,allowing installation in cable trenches,cable wells,on utility poles,etc.
1.The cable grounding box is a specialized device for protecting cable sheaths,preventing damage from lightning strikes and induced overvoltages.
2.The cable grounding box is installed between the cable sheath and the ground.The connecting wires must withstand the residual voltage of the protector,and the connection loop should be as short as possible.The device must be reliably grounded.
3.This product cannot continuously withstand power frequency overvoltages beyond its rated capacity.
4.As an optional feature,this product can be equipped with an action counter.Users may select it as needed and specify the requirement when placing an order.
5.During product installation,first open the cover of the cable sheath protection box.Pass the connecting wire linked to the metal sheath of the cable and the grounding wire through the inlet pipe of the cable sheath protection box.Crimp the terminal,fit the heat shrink tube properly,and connect the terminal with bolts.Then wrap rubber self-adhesive tape around,heat and shrink the heat shrink tube to ensure reliable sealing at the inlet of the grounding box and the incoming cable.Finally,cover the grounding box lid and tighten it with screws for sealing.
6.The external dimensions and installation measurements of the grounding box shall be subject to the actual product.
7.After the protective grounding box and cross-bonding grounding box have been in operation for one year,preventive tests should be conducted on the protector.The test items include:
(1)DC 1mA voltage measurement:
Apply DC voltage(with a ripple of no more than±1.5%)across both ends of the protector.Once the current flowing through the protector stabilizes at 1mA,read the voltage value.This value must not be less than the DC reference voltage specified in Table 1.
(2)Insulation resistance test:
Use a 2500V megger to measure the insulation resistance of the protector.There is no specified value for the insulation resistance,but each measurement result should be consistent,and there should be no short circuits,poor contacts,or short-circuit phenomena.
VII.Ordering Conditions
When ordering cable grounding boxes,please specify:
1.The type of grounding box(direct box,protective box,or cross-bonding box);
2.The rated voltage level of the power cable,or specific performance parameter requirements for the cable sheath protector.
3.The outer diameter and conductor cross-sectional area of the grounding cable between the cable shielding layer and the grounding box.
4.Whether a counter needs to be added to the protective enclosure;
5.Whether it is necessary to monitor the grounding current of the cable shielding layer in the direct enclosure;
6.Order quantity and delivery time.
If users have special requirements,they should be raised at the time of ordering.
8.In case of version changes,no further notice will be given.
