Ball Pressure Test Apparatus : Understanding Ball Pressure Test for Insulating Materials

Plastic and insulating materials are widely used in electrotechnical equipment, subassemblies and components. Although these materials provide good electrical insulation performance, their heat resistance under high-temperature conditions is critical to product safety. So, how can manufacturers verify whether insulating parts can withstand thermal stress and avoid deformation or failure at elevated temperatures? One widely adopted method is the ball pressure test, which assesses the heat resistance of electrical enclosures and external insulating parts. In this article, we will introduce the basic principles of the ball pressure test, cover applicable standards, key test procedures, and the technical specifications of the SN2137 ball pressure test apparatus.

The ball pressure test is a standard test method to evaluate the heat resistance of solid electrical insulating materials (excluding ceramics). This test is mainly applied to insulating parts of electrotechnical equipment and its subassemblies and components. During the test, a pre-conditioned specimen is placed on a preheated test stand inside an oven and loaded with a specified force through a steel ball. After maintaining the set high temperature for 1 hour, the load is removed, the sample is cooled down, and the indentation left on the specimen is measured for judgment. It is critical to ensure the test stand reaches and maintains a stable test temperature before starting the test.

The Ball Pressure Test Apparatus is designed to meet a series of international IEC standards: IEC 60950-1:2013 clause 4.5.5, IEC 60335-1 clause 30.1, IEC 60884-1 2013 clause 25.2, 25.3 and figure 37, IEC60695-10-2(2003), IEC60320-1, IEC60598-1 and other related standard requirements. These standards are commonly required for safety testing of household appliances, plugs, sockets, luminaires and IT equipment.

• Ball Diameter: Ø5mm ±0.05mm (R=2.5mm)
• Ball Pressure: 20N±0.2N (includes loading device and ball)
• Test Stand: 100mm high × 50mm diameter, hole diameter:1.2mm
• Main Material: 304 Stainless steel
• Ball material: bearing steels (in accordance with ISO 3290-1)
• Temperature Probe: A type K thermocouple (0~1000°C)

Ball pressure testing targets insulating materials that may be exposed to heat in service, widely used in these fields:

• Household appliances: Plastic enclosures, insulating supports and internal insulating components
• Electrical accessories: Plugs, sockets, couplers and connection parts
• Lighting products: Lamp housings, insulating bases
• IT & power equipment: Equipment casings and insulating structural parts
• Solid electrical insulating material manufacturing: Material R&D, incoming quality control
• Third-party testing laboratories: Safety compliance testing for electrical products

The test temperature and acceptance criteria are determined according to the corresponding product safety standards.

Q1: What is the test duration for ball pressure test? The specimen with loading device and steel ball shall be kept in the oven at the specified elevated temperature for one hour. Q2: What material is the test ball made of? The ball adopts bearing steel complying with ISO 3290-1; the test stand is made of 304 stainless steel for stable performance at high temperature. Q3: Is this test suitable for ceramic insulating materials? No. The standard scope excludes ceramics. This test applies to solid electrical insulating materials except ceramics. Q4: What do we measure after finishing the ball pressure test? After cooling the specimen, we measure the indentation produced by the steel ball on the sample to judge whether the material meets the heat resistance requirement.

Ball pressure test is an essential safety test to verify the thermal resistance of insulating parts of electrical products. It helps engineers and labs confirm that insulating components will not soften and deform under expected operating temperatures. Sinuo provides SN2137 Ball Pressure Test Apparatus to support laboratory heat resistance testing of insulating materials. Contact our team to discuss your testing standards, specimen requirements and laboratory configuration.