Custom Electrical Penetrations

Product Description

SCHOTT Eternaloc® glass-to-metal-sealed (GTMS) penetrations are used in special applications that secure the energy supply in compressors and pumps for fermentation gas, methane and other critical gases.

Our custom electrical penetrations deliver the most reliable, service-free containment penetrators, particularly when highly critical media are involved.

We have the capability to design and manufacture custom electrical penetrations according to the customer's specifications, in both small lots as well as large series:
  • Housing material can be made from stainless steel or other alloys
  • Thermo-couple, coax and triax penetrations can be produced upon request
We use the compression-seal technique for the steel flange with sealed-in nickel-iron or copper conductors. Sealing between the penetration and the counter surface of the electrical device is usually accomplished by an o-ring or a metal seal and can be bolted, screwed or welded.


With more than 50 years of experience and leading engineering know-how, we’re able to carry out customer-specific development of safety-related cable and thermocouple penetrations.

In addition, our custom electrical penetrations are fully maintenance-free ("fit and forget").


Our hermetically sealed penetrations are well-suited for special applications, which secure the energy supply in compressors and pumps for fermentation gas, methane or other critical gases.

Technical Details

The glass preform, metal shell and conductor pins or tubes for thermo-couples, made of nickel-iron alloy, are assembled on a fixture. The complete assembly is heated to a temperature where the glass becomes free-flowing and fills all the gaps between the metal parts.

During the cooling process, the glass solidifies at its set point. Upon further cooling, the outer metal housing shrinks more than the glass seal (due to its higher coefficient of thermal expansion), leading to a compressive radial force onto the glass body. This leads to an increased hermeticity and tightness even under high temperature or gas pressure.

The nickel-iron conductor pins are plated with a gold or silver finish.

Features / Specifications

  • Rated Voltage: Up to 13 kV AC
  • Rated Current: Up to 1200 Amps per pin
  • Short Circuit Load: Up to 120 kAmps peak
  • Shock Load Tested: Up to 190 g in mated condition, 2,000 g penetration only
  • Vibration Tested: Up to 5 g @ 5 – 100 Hz (higher values are possible)
  • Operation Pressure: Up to 1000 bar
  • Operation Range: From -200°C to + 450°C
  • Up to 60 years qualified lifetime for the assembly (unlimited lifetime for the pressure boundary)
  • Hermetically sealed fiber optic penetration available

Forms of Supply and Product Packaging

We can deliver products in accordance to customers’ dimensional requirements. Upon request, we can also deliver sockets and o-rings.

Our products are delivered in dust-safe, moisture-safe, impact-proof transportation boxes.


During testing, we determine the quality by testing the penetrations at:
  • test pressure: 1.5 x design pressure
  • leakage test (<10-8  mbar.l/s)
  • insulation resistance
  • visual inspection
  • dimension control
For more information, please refer to our quality assurance processes.
Exhibitions & Events
Exhibition CIOE - China International Optoelectronic Exposition, Shenzhen, China, 09-01 to 09-03-2021
Exhibition Gastech, Singapore, Singapore, 09-13 to 09-16-2021
Electronic Packaging
SCHOTT North America, Inc.

15 Wells Street
Southbridge, MA 01550
E-Mail to SCHOTT+1 (508) 765-7450
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