Pressure and Vacuum Sealed Feedthroughs from TC Ltd.
01895 252222 |

Series WFS Pressure and Vacuum Sealed Feedthroughs for Kapton® Wires

Need advice on choosing
a Feedthrough?

Contact one of our engineers on
01895 252222 or send us an email

When multiple wires must pass through a pressure boundary, series WFS feedthroughs can provide an efficient seal without recourse to epoxies or other non-adjustable fixture methods.

Supplied fitted with Kapton® insulated wires with a choice of sealant materials. Available as copper wires or thermocouple wires.

Series WFS feedthroughs seal wires 0.5mm dia. to 3.2mm dia. (24 AWG to 8 AWG). There are four body sizes (1 to 4) having 1/8", 1/4", 1/2" and 3/4" process connections with BSPT (conical gas or DIN 2999 'R') and NPT threads along with ISO, SAE and UNF threads as shown in the Feedthrough Sizes section.

Spectite® feedthroughs are designed for ease of assembly and installation. Wires can be adjusted, removed and replaced when not under pressure or vacuum conditions.

  • Seal on Kapton® insulated copper or thermocouple wires
  • Guide pressure range: Vacuum up to 700 bar
  • Temperature range: -200°C to +230°C
  • 316L Stainless steel wetted parts
  • Choice of sealant materials
  • Individual wires can be replaced without complete disassembly
  • Reusable fitting - sealant and internal components replaceable
  • ATEX / IECEx Approved versions to Ex II 2 GD, Ex d IIC Gb / Ex e IIC Gb, Ex ta IIIC Da available, please contact us for more details
Standard Body Style ('A' Cap) Threaded Extension ('B' Cap) Weld Neck Flanges
Standard body style suitable for most applications. Allows the gland to be terminated into the process as well as to a terminal head or conduit at the opposite end to the process. Supplied without thread for permanent installation into the process by welding.
Specify as 'WELD' for the thread size in the order code.
For termination to a mating flange within the process, see Optional Flanges for details of the flanges available as standard.
Size 1 (1/8" Thread or equivalent) Size 2 (1/4" Thread or equivalent) Size 3 (1/2" Thread or equivalent)
Standard Thread Sizes Standard Thread Sizes Standard Thread Sizes
1/8" BSPT, 1/8" BSPP, 1/8" NPT 1/4" BSPT, 1/4" BSPP, 1/4" NPT 1/2" BSPT, 1/2" BSPP, 1/2" NPT
Alternative Thread Sizes Alternative Thread Sizes Alternative Thread Sizes
M8x1.0, 3/8" UNF-24 M10x1.0, 7/16" UNF-20 3/8" BSPT, 3/8" BSPP, 3/8" NPT
M10x1.0, 7/16" UNF-24 M12x1.5, 1/2" UNF-20 M14x1.5, 7/16" SAE-20, 9/16" UNF-18
    M16x1.5, 1/2" SAE-20, 5/8" UNF-18
    M20x1.5, 9/16" SAE-24, 3/4" UNF-16
Size 4 (3/4" Thread or equivalent)  
Standard Thread Sizes
3/4" BSPT, 3/4" BSPP, 3/4" NPT
Alternative Thread Sizes
M22x1.5, 3/4" SAE-16, 7/8" UNF-14
M24x2.0, 7/8" SAE-14, 1" UNF-14
Sealant Material Code Colour Example Operating Temperature Range Re-usable Material definition and properties
Neoprene N Green -40°C to +90°C Yes Synthetic rubber based on polychloroprene. The elastic properties of the polymer are enhanced by vulcanization. It is much more resistant to heat, light, oxidation, and petroleum than ordinary rubber.
Viton® V Brown -40°C to +225°C
(intermittently to +285°C)

Fluoroelastomer. Resists hydrocarbons, corrosive chemicals and petroleum. Solvent, acid and base resistant. Low permeation rate. Mechanically robust at high temperatures.

PTFE T White -200°C to +250°C Yes Polytetrafluoroethylene. FDA approved grade to Title 21-CFR 17. 1550 and is approved to US Pharmacopoeia Class VI. Has smooth, non-wetting, hydrophobic surfaces that resist biofilm buildup and the lowest coefficient of friction of any solid material. Low thermal transfer.
Graftite™ G Grey / Black -200°C to +550°C
(to +870°C in a reducing atmosphere)
No Graphite 98% purity. Impermeable to gases and liquids. Resistant to most media, not 'wetted' by molten metals or salts. Asbestos-free. No ageing or embrittlement. Good resistance to thermal shock. Conductive material (not electrically isolated).
Lava L Grey Stone -200°C to +870°C No

Natural Magnesium Silicate (Soapstone, Steatite or Rock Talc). Crushes to a powder when compressed. Hygroscopic. Porous to light gases. Unsuitable for use with liquid media and in most vacuum applications.

Other sealant materials may be specified, usually for the individual special requirements of particular applications. Please contact us for assistance.
Style 'A' (Supplied as standard) Description Style 'B' (Alternative cap) Description

Standard Fitting with single thread for direct mounting into process.

Standard Fitting with a Style B threaded extension for conduit/terminal head or enclosure connection. The thread form is the same as the process thread unless otherwise specified.

If a different thread form is required, please specify after the 'B' in the order code, for example:
WFS2 - 1/4" BSPT - 24K - 4 - V- B - 1200mm - 1200mm - NPT

If a B cap is used with a weld neck fitting, then the thread form must be specified.

Style Example Part Code Maximum Compatible
Body Size
KF FLANGE KF16 Size 2 30mm 5.08mm
KF25 Size 3 40mm 5.08mm
CF FLANGE DN16CF Size 3 33.8mm 7.6mm
DN25CF Size 4 54.0mm 11.9mm
All flanges are supplied in 304L stainless steel as standard. Hygienic and Food Grade Flanges are also available - please contact us for further details.
CF Flanges are non-rotatable (fixed) type and comply with ISO3669-2017.
KF Flanges are compatible to the ISO Standard 2861 Specification.
Many other styles of flange available on request (DIN, JIS, ANSI, etc.), contact TC Ltd. for details.

Body Size, Pressure Guide and available Bore Sizes for BSPT, BSPP and NPT Threads2
Kapton® insulated wires - Max 230°C rated

Body Size No. of
Size 1 (1/8") No. of
Size 2 (1/4") No. of
Size 3 (1/2") No. of
Size 4 (3/4")
G* L N T V G* L N T V G* L N T V G* L T V
Wire Size The maximum guide pressure value (in bar) at 20°C is shown for each sealant material according to element size1.
These ratings are a guide and the suitability of any of the products described herein for a particular application
is entirely at the discretion of the purchaser as being the best judge for that particular application.
AWG diam. (mm)
24 Cu or T/C 0.5 2, 4 300 400 250 250 250 2, 4 300 400 250 250 250    
20 Cu or T/C 0.8   2, 4 700 700 400 250 450 6, 8, 12 550 550 250 350
18 Cu 1.0
16 Cu 1.3
14 Cu 1.6   4, 6, 8
12 Cu 2.0
10 Cu 2.5   2, 4
8 Cu 3.2   3
Series WFS feedthroughs are supplied with Kapton® insulated copper or thermocouple material wire to specified lengths, if required. The wires are fitted in the feedthrough, both ends of each wire, or Thermocouple pair, are identified with numbered markers and the feedthrough is torqued ready for installation.

* Graftite™ sealants are conductive. Extra care must be taken where high voltages are present. Please contact TC Ltd for further guidance.
  1. The guide pressures shown for each type of sealant are at 20°C. Spectite® feedthroughs from TC Ltd. have been designed to provide an efficient seal on the elements and restrain them from moving under pressure and vacuum. It is good installation practice to provide additional, mechanical restraint to the elements when differential pressure exceeds 50% of the feedthrough guide pressure value at 20°C. With an increase in temperature, a reduction in the maximum guide pressure value can be expected. These ratings are a guide and the suitability of any of the products described herein for a particular application is entirely at the discretion of the purchaser as being the best judge for that particular application.
  2. Other types of process connection are available, see Feedthrough Sizes.

Current ratings for Kapton® insulated copper wire:

Wire Size (AWG) 24 20 18 16 14 12 10 8
Max. current rating (A) at 230°C 600V AC / 850V DC max. 5 9 13 17 24 30 40 55
Size 1 (1/8" Thread or equivalent) Size 2 (1/4" Thread or equivalent) Size 3 (1/2" Thread or equivalent)
Size 4 (3/4" Thread or equivalent)  
Please note: the overall length will vary slightly depending on the sealant used and the tube size.

Enquiry Form - Feedthrough for Kapton® Wires

1. Feedthrough Body Size

2. Thread Size

3. Element Diameter

3. Element Diameter

3. Element Diameter

3. Element Diameter

3. Element Diameter

4. Element Type

5. Number of Elements

6. Sealant Material

7. Cap Style

7a. B Cap Thread Size (other)

8. Wire Length CAP SIDE

Enter 'NONE' if not required.
9. Wire Length PROCESS SIDE

Enter 'NONE' if not required.
10. Optional Flange

11. Quantity Required

Additional Information

If you are unsure about the specification of the fitting you require, please use the box below to tell us about your application and one of our experienced engineers will call you back to help guide you through the selection process.

Otherwise, please use the drop down boxes provided and we will arrange for a quotation to be sent to you.

Contact Details

Send Enquiry
We will only use your email address to contact you. We will never give your email address to 3rd parties and we do not sell data on to any other company.