Terminals and Connectors - What are the different types and when should I use them?
Read time: 4 minutes
What is an Electrical Terminal?
It is a device attached to the end of a conductor to enable it to form a physical connection to another compatible device in order to reliably and safely pass electrical current or signals.
What are the different types of electrical connectors and terminals?
Bootlace ferrules are an electrical connector commonly known as cord end terminals. This type of wire connector is typically used on flexible multi stranded wire that is to be connected to a terminal block or other connector. They are available in 3 basic types:
The benefits are as follows.
- Effectively converts a stranded conductor into a solid conductor, for a robust, reliable termination with a screw down style terminal.
- Prevents the conductor from fraying leading to conductor loss and reduction in current carrying capacity.
- Prevents conductor damage during handling, connection, or re-connection.
- Much faster, more convenient, and safer than tinning the ends with solder.
The insulated versions come in 2 main colour coding versions:
French and
German.
Pre-insulated crimp terminals are typically used for low voltage small conductor connections to a variety of different electrical connectors. By far the most common type of insulation material is PVC (or Vinyl) with typically a flared coloured vinyl entry to ease insertion of a stripped wire end.
The Red, Blue, Yellow colours correspond to the size of conductors they accommodate:
- Red is for 0.25 - 1.5mm ² or 22 - 16AWG
- Blue is for 1.5 - 2.5mm ² or 16 - 14AWG
- Yellow is for 4 - 6mm ² or 12 - 10AWG
Typical terminal connector types:
There are more specialist materials available including halogen free polycarbonate and PA6.6 Nylon insulation. Vibration resistant designs incorporate an additional copper sleeve between the terminal insulation and the wire insulation which when crimped provides a more secure grip of the wire.
Available but less commonly used by electricians are uninsulated versions of these terminals.
Copper tube terminals are a type of electrical connector commonly referred to as copper lugs. These terminals carry significant electrical current and good crimping practice for secure termination is essential.
These heavy-duty terminals are designed for conductors from 1.5 mm all the way up to 1000 sq. mm and must be able to cope with sustained loads of the maximum electrical current the conductor is rated to.
They are made from seamless copper tube with a wall thickness specified such that the x-sectional area of the terminal exceeds that of the conductor itself ensuring its current carrying capacity. Typically, these are terminated with an indent style hand crimp tool for the smallest sizes, graduating to a ratchet hex die tool, and ultimately a hydraulic hex die tool for the larger sizes.
You must ensure you use the terminal manufacturer's matched crimp tooling as small variances in terminal dimensions will have a very significant effect on the ultimate crimp tool pressure and the resulting crimp performance. Operator awareness of, and adherence to, the manufacturer’s crimp selection/tooling and installation instructions is critical for a safe and reliable termination.
Specialist Terminals
The previous sections covered the most common types of terminals used by electricians. There is also a wide array of other less commonly-used terminals, such as:
We don’t list all these specialist electrical terminal connector types on our website, but we can provide you with help, information and pricing if you send an inquiry to sales@expresselectrical.co.uk.
With such a wide array of terminals, there is a correspondingly vast array of crimp tools available from low-cost hand tools right up to battery and hydraulic tools to crimp the largest terminals.
The most important fact to remember is that terminals and tooling are two parts of a “system” and using the wrong tooling or mixing your tooling manufacturer and terminal manufacturer breaks this system and will give unreliable results.
🔎 Looking for something not on our website?
Only our most popular crimp connector types are listed on the website. We are also able to order additional products from the Cembre, Klauke and expressTERM Catalogues.
Contact our sales team at sales@expresselectrical.co.uk with quantities and part numbers for a quote!