5 types of electrical terminations: how to choose the right ones 

Selecting the correct electrical termination is not a formality. This is a decision on which the safety of the line, the service life of the cable and the stability of the entire distribution network depend. We regularly see how, in 10-35 kV projects, replacing one type of coupling with another solves the problem of repeated flashovers during lightning surges. Or how an incorrectly selected tip causes local overheating after only 8 months of operation in conditions of high humidity and temperature cycles. All this is not a theory. This is data from our tests in the laboratory up to 1000 kV and feedback from 147 energy supply companies in the CIS countries and the Middle East.

5 types of electrical terminations: how to choose the right ones

Electrical terminations are not just “plugs” at the end of a cable. These are engineering solutions that compensate for field strength, seal the joint, provide mechanical fixation and heat removal. An incorrect choice leads to partial discharges, corrosion of current-carrying conductors, destruction of insulation and emergency shutdown. Below are five main types, grouped by installation principle and application.

• Heat shrinkable end seals— work due to the memory of the polymer shape when heated. They require strict adherence to temperature conditions (110–130°C) and holding time. Ideal for copper and aluminum cables with PVC and cross-linked polyethylene insulation up to 35 kV. Our series modelsHST-KTtested at −40°C and +60°C without loss of adhesion.

• Cold shrink end seals- based on pre-stretched elastomeric material. They are mounted without heating, which is critical when working near explosive zones or in rooms with limited access. The main condition is the cleanliness of the surface and strict adherence to the technology for removing the protective film. They are especially in demand in the modernization of existing networks.

• Split terminations type "H"— provide quick replacement of equipment without opening the cable line. They are used in complete transformer substations, distribution cabinets and at building entrances. Our seriesHST-HRwithstands up to 25 connection/disconnection cycles without reducing contact resistance.

• Compression tips (removable)— used for connecting cables to buses, circuit breakers and switches. The key parameter is the correspondence between the core cross-section and the tip material (copper/aluminum). Incorrect selection of crimp is the cause of 68% of cases of overheating at connection points.

• Cast endings (fill-in)— used in extreme conditions: high humidity, chemically aggressive environment, constant vibration. Filled with epoxy resin directly at the installation site. They require highly qualified performers and precise adherence to the proportions of the components.

One of the most frequently asked questions is: “Can heat shrink be replaced with cold shrink?” The answer is yes, but only after recalculating the electric field and checking compatibility with the cable sheath. For example, for cables with aluminum armor, we recommend only specially adapted versions of cold-shrinkable sleeves - standard samples do not provide sufficient protection against stray currents.

Clients often underestimate the role of climate control solutions. For areas with sharp temperature changes (for example, Kazakhstan, Siberia, Armenia), we supply terminations with an increased elasticity of the silicone shell and a reinforced sealing system. A conventional coupling here can lose its tightness within a year, but ours has been working without failure for more than 12 years.

Shijiazhuang Hist Electric Co., Ltd. does not just produce 5 types of electrical terminations. We design them for specific conditions: type of soil, level of air pollution, frequency of thunderstorms, mechanical loads during installation. Each batch undergoes incoming inspection of raw materials, intermediate checks at all stages of assembly and acceptance tests in our own laboratory. This allows us to guarantee stable quality regardless of the order volume - from 10 pieces to 5000.

If you choose termination for a new object, start by calculating the electric field in the area of the cable end. If this is an upgrade, check the compatibility of the new solution with the old cable and fittings. And always consider who will install it: heat shrink requires trained personnel and a heat gun, and cold shrink requires strict adherence to instructions and control of cleanliness.

The correct choice of 5 types of electrical terminations is not a compromise between cost and reliability. This is an accurate engineering calculation that takes into account the physics of processes, operating features and real installation limitations. This is how we work with every order - from the initial technical request to warranty support throughout the entire service life.