Electrical feedthroughs that carry power and signals through the wall of vacuum chambers and sealed enclosures · Flange size and seal, connector and pin count, current per pin, insulator and pin materials, leak rate, operating pressure and temperature range, dimensions and weight
An electrical feedthrough carries wires through the wall of a vacuum chamber, pressure vessel or sealed enclosure without breaking the seal. It must hold vacuum or pressure, insulate each conductor and survive the temperatures of bake-out or service. Ask three things first: what flange or mounting the wall offers, how many conductors at what current and voltage must pass, and what leak rate, pressure and temperature range the system requires.
Electrical feedthroughs for vacuum chambers and hermetic or pressure enclosures: multi-pin signal, power and instrumentation feedthroughs on CF, KF and similar flanges. Cable glands (see aluminium cable gland), wall bushings for high-voltage power (see high-voltage insulating bushing), fibre-optic and rotary motion feedthroughs are outside this page.
01
attocube's EVFT 40CF spec sheet describes a DN40 CF feedthrough (69.8 mm flange outside diameter) with one Sub-D-15 male connector to DIN 41652/MIL-C-24308, 1 mm gold-coated NiFe pins, a glass-ceramic electrical seal in a 316L stainless steel flange sealed with a copper gasket, 3 A continuous and 5 A maximum current per pin, and a weight of 343 g. [1]
The EVFT 63CF sheet describes a DN63 CF version (114.3 mm flange) with three Sub-D-15 connectors in the same materials and the same per-pin current ratings, weighing 1,111 g; the gasket is not included with either. [2]
Editorial calculation: three Sub-D-15 connectors give 45 pins on the DN63 flange against 15 on the DN40 flange (3 × 15); at 3 A continuous per pin, any conductor needing more current must be split across pins or carried by a power feedthrough. [1] [2]
Give the supplier the chamber flange type and size (CF, KF, ISO or custom), number of conductors and type (signal, power, thermocouple, coaxial), current and voltage per conductor, connector on air and vacuum sides, insulator and conductor materials, required leak rate and test gas, operating pressure, bake-out and operating temperature range, and whether the gasket and mating connectors are included.
02
Both attocube feedthroughs list a maximum helium leak rate of 5×10⁻¹⁰ mbar·l/s, an operating pressure of 5×10⁻¹¹ mbar (UHV) and an operating temperature range of −200 °C to 230 °C, with a CF copper-gasket seal fixed by screws. [1] [2]
Editorial note: leak rate, ultimate pressure and bake-out temperature are different specifications; ask for the helium leak test certificate and confirm the temperature limits of connectors and cables on both sides, which can be lower than the feedthrough's.
03
Accu-Glass Products lists its Subminiature-D CF feedthroughs with 9 to 100 pins per Mil-DTL-24308, gold-plated Ni-Fe pins in a glass-ceramic seal and 304 stainless shell, rated 500 VDC and 5 A per pin at 20 °C, with a note that no more than 20% of the pins on a feedthrough may carry the maximum pin current at the same time. Its electrical ratings are maximum test values with the vacuum side at or below 1×10⁻⁴ Torr; it states a He leak test to 5×10⁻¹⁰ standard cc/s, UHV to 1×10⁻¹⁰ Torr, −200 to 250 °C for the feedthrough, connector and cable limits of 80 °C (air), 250 °C (UHV PEEK) and 125 °C (HV DAP), a 25 °C/min maximum thermal gradient, and that assembly ratings follow the lowest-rated component. [3]
Kurt J. Lesker states that its feedthrough electrical ratings are based on one side in dry atmosphere and the other in vacuum below 1×10⁻⁴ Torr, and that the ratings are safe operating limits set by materials, mechanical design and environment. [4] Accu-Glass's fluted-ceramic HPF-20-275 lists stainless steel, ceramic and copper construction and a weight of 1.5 lb. [5]
Editorial calculation: 5×10⁻¹⁰ standard cc/s is about 5×10⁻¹⁰ × 1.013 ≈ 5.1×10⁻¹⁰ mbar·l/s, in line with the 5×10⁻¹⁰ mbar·l/s quoted above; 1×10⁻¹⁰ Torr is about 1.3×10⁻¹⁰ mbar. Under the 20% rule a 50-pin feedthrough may carry 5 A on at most 10 pins at once. Ratings stated at ≤1×10⁻⁴ Torr do not cover the pressure range in between, so ask for voltage ratings at your process pressure. [3] [4] [1]
| Published feedthrough | Conductors | Rating | Bake / temperature |
|---|---|---|---|
| Sub-D CF, glass-ceramic seal | 9–100 pins | 500 VDC, 5 A per pin (20% of pins at max) | −200 to 250 °C; 25 °C/min |
| Fluted ceramic power, 2.75" CF (HPF-20-275) [5] | 1 copper conductor | 20 kVDC, 150 A | 250 °C bake and operating; 1×10⁻¹⁰ Torr |
| Mil-Spec MIL-C-5015 multi-pin, CF, double-ended | Alumina-insulated Alumel wires | 700 V, 10 A per conductor | Bakeable to 350 °C with air cable off; vacuum plug −196 to 350 °C; air plug 0 to 125 °C; 25 °C/min |
State the pressure at which each voltage rating must hold, how many pins carry full current at once, bake temperature with cables connected or removed, and maximum heating and cooling rate.
04
attocube leaves the copper gasket out of both its feedthroughs, so settle the last row in the order rather than assume it. [1] [2]
| Part | Role | Fix in the order |
|---|---|---|
| Flange | Mount on the chamber. [1] [2] | Size; material; seal type. |
| Insulating seal | Hold vacuum and insulate pins; glass-ceramic or alumina. [1] [3] [4] | Glass-ceramic or ceramic. |
| Pins or conductors | Carry current and signals. [1] [2] | Material; diameter; current. |
| Connectors | Connect cables on each side. [1] [2] | Type; pin count. |
| Gasket | Seal the flange joint. [1] | Material; included or not. |
05
The voltage and current figures here belong to three different designs — a Sub-D signal feedthrough, a Mil-Spec multi-pin and a 150 A power conductor — so read each against the type you need. [3] [4] [5]
| Field | What it means and published values | Ask the supplier for |
|---|---|---|
| Rated Voltage | Voltage per conductor; 500 VDC (Sub-D) [3], 700 V (Mil-Spec) [4], 20 kVDC (power). [5] | Value; test voltage. |
| Rated Current | E.g. 3 A continuous, 5 A maximum per pin [1] [2]; 10 A per wire [4]; 150 A power conductor. [5] | Per pin. |
| Contact Resistance | Resistance through each pin. | Value. |
| Insulation Resistance | Between pins and to flange. | Value. |
| Dielectric Strength | Ratings at ≤1×10⁻⁴ Torr vacuum side. [3] [4] | Test voltage. |
| Operating Temperature | E.g. −200 °C to 230 °C [1]; bakeable to 350 °C with air cable removed. [4] | Range; bake-out. |
| Leak Rate | E.g. 5×10⁻¹⁰ mbar·l/s He maximum. [1] [2] | Value; test certificate. |
| Ingress Protection | For non-vacuum hermetic enclosures. | Rating. |
| Number of Conductors | E.g. 15 or 45 pins. [1] [2] | Count. |
| Conductor Size | E.g. 1 mm pins. [1] | Diameter. |
| Mounting Thread | Flange or threaded mounting, e.g. DN40/DN63 CF. [1] [2] | Flange or thread. |
| Body Material | E.g. 316L stainless steel flange. [1] | Material. |
| Thermal ramp | 25 °C/min maximum in two makers' data. [3] [4] | Heating and cooling rate. |
06
Paste it into your enquiry below or into an email to a maker, then replace every bracket.
Mounting: [flange type and size] Conductors: [count; type; current; voltage] Connectors: [air side; vacuum side] Materials: [insulator; pins; flange] Vacuum: [leak rate; operating pressure] Temperature: [bake-out; operating] Scope: [gasket; mating connectors; cables] Volume: [quantity]
Manufacturer profiles associated with Electrical Feedthrough.
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
One multi-pin Sub-D feedthrough lists 3 A continuous and 5 A maximum per pin. [1]
One maker lists a maximum helium leak rate of 5×10⁻¹⁰ mbar·l/s for use down to 5×10⁻¹¹ mbar. [1] [2]
One glass-ceramic sealed design is rated from −200 °C to 230 °C. [1]
One maker allows the maximum pin current on no more than 20% of the pins at the same time. [3]
Sources checked 2026-10-12. attocube's EVFT 40CF and 63CF spec sheets, Accu-Glass Products' Sub-D and HPF-20-275 product pages and Kurt J. Lesker's Mil-Spec multi-pin page are makers' publications for specific vacuum feedthroughs, cited as examples of the parameters a feedthrough specification covers, not endorsements.
Ask for use case, specification boundaries, supplier type, and RFQ preparation information for this product.
Compare manufacturer profiles with relevant product and process capability.