Because of their reliability, convenience and economy, pressure connectors have received widespread acceptance as suitable methods of making electrical connections. Pressure connectors are also designed to apply and maintain pressure between the contact surfaces by means that may be classified as:
- Clamp type
- Compression type
Clamp-type connectors apply and maintain pressure by means of clamping bolts, wedges, springs or combinations of such elements, e.g. linetops, connectors.
Compression-type connectors apply and maintain pressure by compressing the connector around the conductor with suitable compression tools. The principal purpose of this pressure is to establish and maintain suitable low contact resistance between the contact surfaces of the conductors, in order to carry the electrical load without overheating. The pressure also provides the mechanical grip required for the application.
Cables can be connected by mechanical means, including:
- Tunnel or screw-type connections;
- Compression fittings.
- Use the correct size of compression tool for the given lug type.
- Ensure that the lug design is such that any indentation tool used will indent the top of the lug.
- Apply constant, even pressure to the crimping tool, making sure that the indentation will hold the conductor securely.
- Keep the insulation butted against the lug whore possible.
- Check that the insulation is not clamped under the connection.
- This would produce a bad connection.
Crimping tool types
The crimping tool illustrated is of a type which crimps from 0.5 to 6 mm2 cables. The automatic, pre-set crimping tool crimps 0.5 to 6 mm2 cables and has an automatic predetermined depth control.
Cables from 10 to 120 mm2 may be crimped using an adjustable crimper. The size of the crimp is set by rotating the adjusting screw and lining up the mark on the jaws with the scale on the crimper.
Large cables require much force to be exerted during the crimping operation. For these, hydraulic crimpers are used.