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Backshells

Servo Connectors offers backshells from KEC, Yeonhab and Sunbank.

 
KEC KC1100, KC2100, KC2300 and KC2400 Backshells
KEC Backshells
Yeonhab Backshells
Yeonhab Backshells
 
Souriau Sunbank MIL-SPEC Backshells and Dust Caps
Souriau Sunbank Backshells
 
 
 
 
 
 
 
 

What is a backshell?

A backshell is a connector accessory which provides protection to the back-end of a connector plug on the rear thread. They are typically a separate part designed for the series of connector and can be locked onto the plug by screw action to the thread.  Connectors with Integrated Backshells for Banding, Over Molding or Shrink Boots are available in the market.

 

 
KEC Backshells
 

What is the purpose of a backshell:

Backshells are an important accessory that will provide screening protection for the contacts in the connector as the they can be affected by electromagnetic interference (EMI) and radio frequency interference (RFI). Also, they will help protect from other environmental elements, such as dust and moisture. However, they will not typically provide IP68 protection without a heat shrink boot to add further environmental screening. Another benefit is the strain relief that the backshell provides to the cable entry into the plug.

 

Selecting a high performance backshell:

A backshell which can provide improved conductivity for EMC screening of the connector, whilst equalling or going beyond the environmental sealing of the connector would be the ideal optimum selection. The best screening is provided by 360 degree shielding around the whole cable. Even the slightest gap can allow unintended interference from the environment affect the cable system. The cable system designers must consider the cable entry size that is required to select the correct backshell. There are solutions for multiple cable entry sizes being accommodated for with one backshell, such as the KEC Universal Backshell.

 

Struggling with converting wire gauge sizing between imperial and metric? Click here

 

Other considerations for selecting a high performance backshell:

The level of EMI shielding around the cable? This could be 360 degree or individual screening capability.

Do you require the plating finish to be the same as the connector shell?

Does the plating need to be RoHS compliant? Cadmium will unlikely be RoHS compliant. However, Black Zinc Nickel is recommended as an alternative with good conductivity and salt spray resistance.

What level of environmental protection is required? Using a heat shrink boot to add additional environmental sealing to moisture.

Could heavy use place strain on the cable entry? Select a strain relief to protect the conductor terminations. The usual methods are cable clamps, heat shrink boots, tie-posts.

Does the temperature range of the connector equal or exceed that of the application? Check the datasheets for this information.

 

Different types of backshell:

Backshells are available in a variety of types for circular connectors. The most common angles that you will see are:

  • Straight
  • 30°
  • 45°
  • 90°
  • 60°
  • 30°
  • 75°
KEC Backshells 
 

 

 

Screen termination methods:

Many customers have their preferred method of screen termination, from simple cable ties, to springs, band straps, clamps, and metal rings that respond to heat.

Constant Force Spring Ring Bands are re-usable and self-tensioning to secure both overall and individual braid terminations. Spring bands typically do not require tooling and can provide a high level workable strength for the backshell cable system. A high quality spring band will be designed to be corrosive resistant to the environment and have a high tolerance to vibration, shock or extreme temperatures.

Band clamps are a common termination method, that don’t require any special tooling or assembly skills that make them easy and economical to install. The screening braid for the cable is clamped to the backshell with a metal strap.

High quality sleeving and shielding will provide bundling and component protection against abrasion, heat, noise, and electromagnetic interference.

KEC Backshells 

 

Backshell plating finishes:

Black Zinc Nickel – RoHS compliant alternative to Cadmium typically withstanding 500H salt spray. Black Zinc Nickel can be mated with Cadmium with no significant galvanic reaction. Also, benefits from being non-reflective and highly conductive.

Cadmium – a staple for military connectors and backshells with high levels of corrosion resistance, around 500H. Also, benefits from high levels of shell-to-shell continuity.

Electroless Nickel – useful for applications where exposed to high temperatures, such as in industrial applications and benefits from a non-reflective finish.

Zinc Cobalt – enhanced corrosion resistance from standard zinc finishing. Typically withstands up to 350H salt spray corrosion.

 

Conductivity:

Corrosion can affect the shell-to-shell conductivity and the effectiveness of the shielding from interference and grounding. Shell-to-shell conductivity is measured in mOhm in attenuation tests using decibels as the reading. Choosing a plating, which suits the environmental requirement is important in contributing to the longevity of electrical performance of the cable system for the application.

 

Alternative backshells to Polamco 91 Series & BT series, Amphenol, Compaero, ITT Cannon, Yeonhab and Glenair?

Polamco BT Series – KEC KC2500 for overall screening (KC2600 for individual and overall screening)

Servo Connectors believes that the KC2500 series, whilst it is technically an alternative to the Polamco BT series, is the nearest to an equivalent that there is on the market. If you are looking for a backshell where band straps are provided as standard then the KC2500 is a recommended series. However, there is an option to forego the band straps, which is ideal where you currently have a supply in inventory. Use the NS suffix in the part number.  For individual and overall screen termination the KC2600 includes the braid and slotted body.

If you are looking for an alternative to the Polamco 91 series, then Servo Connectors recommends the KEC KC2700 backshell, which does not require any special tooling for the reworkable band clamp. Overall screening is provided, just like the 91 series.

 

Connector series accommodated by KEC backshells:

  • MIL-C-26482 SERIES 1 / PAT 105, 608 & 603
  • MIL-C-38999 SERIES 1 & 2 / PAT 614 & 616 PAN 6433-1
  • MIL-C-83723 SERIES 1 & 3 / MIL-C-26482 SERIES 2 / PAT 602 & PAN 6432-1 & -4
  • MIL-C-38999 SERIES 3 & 4 / METRIC THREAD (EN3645)
  • PAN 6433-2 / LN29729
  • D38999 / 8D Series by Souriau

 

Cross referencing backshell part numbers

Please contact the office to request cross referencing for KEC backshells against existing backshell part numbers.

 

Example backshell cross reference:

Shell Size

13

Plating

Nickel

Termination

Band

Type

Straight

 

KEC KC2500

KEC Universal

Polamco

Yeonhab

Amphenol

KC2501-32-13J1-09

KCS2801-32-13J

BTH1-13-04-1-C-SB

YAR40AC001204XX

BK4SRL12049BN

 

Shell Size

13

Plating

Nickel

Termination

Spring

Type

Straight

 

KEC KC2700

KEC Universal

Polamco

Yeonhab

Amphenol

KC2701-32-13J1-13

KCS2801-32-13J

91H1-13-07-1-C-HE100

YAT40AC001207XX

BK4SRL12079SN

 

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Connector House,
Harden Road,
Lydd, Kent
TN29 9LX
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