Connector Adaptors & Backshell Assemblies - Definitions & Technical Overview

DEFINITIONS
Adaptor type: Solid (sometimes called “fixed”), Spin-Coupling, Shielded, Tinel-Lock® (TXR) & Bandstrap. Each is designed to offer a suitable interface between a connector and a heat-shrinkable moulded part.

Connector code: the connector numerical code to identify connector & adaptor interfaces and part numbers.

Entry size: is the diameter of the hole through which the cable enters into the adaptor. For example, the 08 entry is 12.7mm (0.5in). Entry sizes are specified on Shielded and Tinel-Lock® (TXR) adaptors only.

Ring designator: for Tinel-Lock® (TXR) adaptors; this is a two letter part number to suit the type of cable braid (see PDF below for further information).

Shell size: this is the size of a connector and is normally a two-digit, even number between 08 and 24.

Order number: this is a two-digit number that specifies the size of the adaptor that will mate to the corresponding shell size of a connector. The order number is frequently the same as the connector shell size, but should be independently checked by the user.

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DETERMINING THE ENTRY SIZE
Once you have the wire bundle size, you can use the chart below to select the entry size. This chart shows the minimum entry size for cables from 3mm to 38mm in diameter. In other words, the white spaces on the chart represent all of the cable outside diameters each entry size will fit. Following these steps:
1. Find the cable diameter on the chart
2. Note the lowest entry size that will fit the cable diameter
If the adaptor is shielded or has a Tinel-Lock® ring, there are additional considerations, which are noted in the PDF below.

Shielded Adaptors
The extreme flexibility of the braid on shielded adaptors accommodates a large range of cable diameters. It is therefore recommended that the standard entry size for any given adaptor part number be specified. Use the selection chart above to ensure that the standard entry size will pass over the jacketed cable diameter.

Tinel-Lock® (TXR) Adaptors
With Tinel-Lock® (TXR) adaptors, the cable braid must be opened up to fit onto the outside diameter of the adaptor entry. For optimum performance, select the smallest entry size that will pass over the jacketed cable diameter. Repair of the connector will be easier if a slightly larger than minimum entry size is used.

The selection chart in the PDF below shows the minimum entry size for cable diameters in the range of 3mm to 38mm. This will ensure that the jacketed cable passes through the adaptor for easy assembly. It should be checked to be sure the braid will open sufficiently to fit the entry size selected and to ensure that the braid and boot can be rolled back.

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ROLL-BACK REPAIR FOR ADAPTORS
More than 85% of cable repairs are made within 75mm of the connector, usually as a result of a broken pin or wire. By reheating the heat-shrinkable moulded part and unscrewing the adaptor coupling nut, the moulded part can be “rolled back”, providing access to the rear of the connector. This technique is applicable to spin-coupling, shielded and Tinel-Lock® (TXR) adaptors (providing there are wire loops, then the broken pin or wire can be repaired using this technique). A code of practice is available on request.

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SELECTING THE MATERIAL & FINISH
To ensure optimum compatibility, select the adaptor material and finish to match those of the connector. Additional materials and finishes are also available on request. Further information is available in the PDF below.

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