Reliable sealing is fundamental to ensuring long term performance of electrical systems operating in harsh environments. However, the level of protection required can vary significantly, from electrical installations exposed to rain and dust to specialist equipment operating under a vacuum with little margin for error. Hermetic and environmental sealing are two of the most common options for electrical and data connectors, each offering unique benefits that make them appropriate for different applications. Understanding when each type of sealing is suitable is critical for engineers and technical buyers, as the most appropriate method ultimately depends on the specific environmental and performance requirements. This blog explores the features of environmentally and hermetically sealed connectors, outlines the key differences between them, and explains how to determine when each solution is appropriate for your application.
What is a hermetically sealed connector?
Hermetically sealed connectors are designed to connect two isolated components of specialised electrical equipment without allowing gases or moisture to leak through. They generally use glass-to-metal or ceramic-to-metal bonding techniques to create a gas-tight barrier between the insulating materials and the metallic components, ensuring complete atmospheric isolation. They are designed for use in highly specialised applications where maintaining internal atmospheric stability is critical, and even minimal gas ingress could compromise performance or safety, such as aerospace systems, satellites, defence electronics, vacuum chambers and certain medical or semiconductor environments. To verify this level of protection, manufacturers use helium leak testing to ensure extremely low leak rates under vacuum or pressurised conditions. Because of their precision construction and stringent performance requirements, hermetically sealed connectors are typically more complex and costly than environmentally sealed alternatives.
What is an environmentally sealed connector?
Environmentally sealed connectors are designed to protect electrical contacts from external contaminants such as water, dust and dirt in outdoor and industrial installations. The main intention of this type of sealing is to prevent corrosion, short circuits or impaired performance. Environmentally sealed connectors feature engineered housings, elastomeric seals and O-rings that block moisture and particulate intrusion. They are widely used across industrial automation, renewable energy systems, marine equipment and transportation infrastructure, where connectors must be able withstand harsh weather conditions for long periods of time. In many industrial systems, environmental sealing provides the appropriate level of protection without the complexity associated with hermetically sealed connectors.
Environmental sealing is typically defined through the Ingress Protection (IP) ratings system, providing engineers with a clear framework to specify the correct level of dust and water sealing for their operating conditions.
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Solid particle protection |
Liquid ingress protection |
| 0 - No special protection |
0 No protection |
| 1 - Protection from large body parts and solids bigger than 50 mm in diameter |
1 - Protection against dripping water onto item when mounted upright on a turntable and rotated at 1 rep per minute |
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2 - Protection from fingers or solids up to 80 mm long and 12 mm in diameter |
2 - Protection against vertically dripping water when the item is tilted at 15° from its normal position |
| 3 - Protection from tools, wires or objects larger than 2.5 mm in diameter |
3 - Protection against water spray at any angle up to 60° from vertical, whether that spray is oscillating or has a counterbalanced shield |
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4 - Protection against 1 mm wide solid objects, such as wires, nails, screws, larger insects or other items |
4 - Protection against splashing water from any direction, from an oscillating fixture or one with a spray nozzle with no shield |
| 5 - Partial protection against dust, which may be harmful to equipment |
5 - Protection from water jets when water is projected by a 6.3 mm nozzle onto the enclosure from any direction |
| 6 - Full resistance to dust and other small particulates |
6 - Protection from powerful water jets, i.e., with a 12.5 mm nozzle, projecting water from any direction |
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6K - Protection from powerful water jets with increased pressure using a 6.3 mm nozzle, projecting water from any direction or elevated pressure |
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7 - Protection from ingress of water in an immersion of up to 1 m depth |
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8 - Protection from ingress of water when immersed depths are higher than 1 m of water |
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9K - Protection from powerful high temperature water jets, at close range and at high temperatures |
Hermetically vs environmentally sealed connectors: key differences
Although both connector types are designed to protect electrical systems, they differ significantly in construction, performance standards and intended applications:
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Environmentally sealed connectors |
Hermetically sealed connectors |
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Applications and key considerations
The shift towards renewable energy depends not only on advanced turbines and high efficiency photovoltaic panels, but also on the integrity of the infrastructure supporting them, which must be designed to withstand years of constant use in demanding environmental conditions. While often overlooked, connectors play a crucial role in this resilience, preserving the power and data pathways that keep turbines turning, panels generating and monitoring systems online. Bulgin prides itself on providing the long-term connectivity solutions that modern renewable energy plants rely on, ensuring clean energy can be produced consistently and safely as the world transitions to a greener future.
Environmental sealing for reliable operation in harsh conditions
Environmentally sealed connectors offer dependable long-term performance for most industrial, renewable energy and outdoor systems. Bulgin’s environmentally sealed circular power connectors are designed specifically for these demanding environments, with IP66, IP67, IP68 and IP69K rated options available. Their durable construction delivers robust environmental sealing and resistance to mechanical stress while maintaining reliable electrical performance for a wide range of industrial applications.
Conclusion
Although hermetically sealed connectors and environmentally sealed connectors are both designed to protect electrical systems, they serve different purposes. Hermetic sealing provides gas-tight atmospheric isolation for specialised vacuum or pressure-sensitive environments. Environmental sealing safeguards connectors from moisture, dust and contaminants in industrial and outdoor applications. Recognising this difference enables engineers to choose connectors that match the true demands of their system. In many real-world applications, environmentally sealed connectors provide the appropriate level of protection, supporting durability, reliability and long-term performance.
Explore Bulgin’s range of environmentally sealed solutions to find out more about our power connector engineered for dependable operation in harsh environments.
