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Product description

Applications

The plug-in versions of 3VA molded case circuit breakers are designed for use in complex applications for which speedy replacement of molded case circuit breakers is a basic requirement. Plug-in technology can be used, for example, when clear visual evidence of safe electrical isolation of circuits is essential, e.g. when overhaul work is in progress.

Description

With a plug-in system, the molded case circuit breaker is moved into and out of the plug-in socket manually.

WARNING

Risk of large magnetic forces in the event of short circuits

Accident hazard posed by short circuit events. The molded case circuit breaker can be ejected from its socket by the resulting magnetic forces.

The 3VA molded case circuit breaker must be bolted securely in position in the socket. The complete kit for plug-in technology contains assembly bolts for this purpose.

A complete kit for plug-in technology contains all the components required to convert the fixed mounting version of a 3VA molded case circuit breaker or 3VA switch disconnector to a plug-in version.

A complete kit for plug-in technology contains:

  • Plug-in socket

  • 4 fastening bolts for installing the socket in the cubicle

  • 4 fastening bolts for securing the 3VA molded case circuit breaker in the plug-in socket

  • Plug-in contacts for attachment to the main terminals of the 3VA molded case circuit breaker

    • 3-pole: 6 plug-in contacts

    • 4-pole: 8 plug-in contacts

  • Autotrip plunger

  • 2 screw-mounted terminal covers for the 3VA molded case circuit breaker

  • Cable cages (see chapter Cable cage)

A conversion kit for plug-in technology contains:

  • Plug-in contacts for attachment to the main terminals of the 3VA molded case circuit breaker

    • 3-pole: 6 plug-in contacts

    • 4-pole: 8 plug-in contacts

  • Autotrip plunger

  • 2 screw-mounted terminal covers for the 3VA molded case circuit breaker

  • Cable cages (see chapter Cable cage)

Scope of supply of the 3VA molded case circuit breaker and the 3VA switch disconnector in molded case circuit breaker design:

  • For 3-pole version up to 250 A: 2 assembly bolts

  • For 3-pole version up to 630 A and 4-pole version: 4 assembly bolts

Terminal covers

As described above, two screw-mounted terminal covers are included in the plug-in socket complete kit and the plug-in socket conversion kit. These feature molded grips to ease withdrawal of the molded case circuit breaker from its socket. Since it requires significant force to remove a molded case circuit breaker from its socket, the plug-in terminal covers are bolted to the contact unit.

If the termination area of the plug-in socket needs to be protected by terminal covers, a variety of models of terminal cover are available to order as options for this purpose.

Autotrip plunger

An autotrip plunger is supplied as standard with every complete kit and every conversion kit for converting a 3VA molded case circuit breaker to plug-in technology. The plunger performs safety functions in operation.

When a 3VA molded case circuit breaker is converted to a 3VA plug-in unit, this plunger is installed from the rear of the device and latched. The plunger performs safety functions in operation. It prevents the molded case circuit breaker from being switched to the ON position if the breaker is not correctly bolted to the socket. For further information, see also section "Signal 'Plug-in unit - MCCB correctly bolted to plug-in socket'" in chapter Position signaling switches.

WARNING

Make sure that the autotrip plunger is correctly installed

The molded case circuit breaker cannot be safely moved into or out of the socket without an autotrip plunger. Moving it into or out of the socket when the main contacts are closed (breaker position ON) can cause arcs to form between contacts and result in irreparable damage to the circuit breaker or the electrical installation, and possibly cause physical injury to personnel.

Once installed, the autotrip plunger cannot be dismantled again!

Note the color coding and labels for the autotrip plunger:

  • Plug-in technology: Black, labeled "Plug-in"

  • Draw-out technology: Grey, labeled "Draw-out"

Auxiliary circuit connectors

Molded case circuit breakers or switch disconnectors in molded case circuit breaker design are frequently equipped with internal accessories, e.g. with an auxiliary switch, auxiliary release, etc. A broad range of internal accessory components is also available for the 3VA molded case circuit breaker. For further information, please refer to chapter Internal accessories.

To ensure that the electrical connections required by plug-in units can be quickly and safely disconnected, auxiliary circuit connectors can be installed.

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The breaker-end half is attached to the underside of the molded case circuit breaker and electrically connected to the internal accessories. Appropriate openings and cable ducts are provided in the molded case circuit breaker for routing stranded wires. The plug-in socket half of the auxiliary circuit connector is inserted in the socket and electrically connected to the customer's installation.

When the molded case circuit breaker is inserted into the plug-in socket, the internal accessories in the breaker are quickly connected to the customer's installation without the use of tools.

NOTE

Plug-in and draw-out units use different versions of the auxiliary circuit connector. The draw-out version has a longer, movable telescopic rail because the distance to be bridged in the draw-out socket is longer.

Further details about auxiliary circuit connectors can be found in chapter Auxiliary circuit connector.

Position signaling in the plug-in socket

Several position signaling switches (number depends on socket size) can be fitted in the plug-in socket. Auxiliary switches are capable of signaling "Plug-in unit - MCCB correctly bolted to plug-in socket" via electrical connections.

For further information, please refer to chapter Position signaling switches

Padlocks for preventing insertion of a molded case circuit breaker

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The socket unit can be locked by padlocks to prevent the insertion of a 3VA molded case circuit breaker while maintenance or overhaul work is in progress. Using these locks to prevent insertion and operation of a molded case circuit breaker helps to protect personnel and the installation itself. The socket unit of the plug-in socket is equipped with three openings for padlocks.

Openings for padlocks:

  • Up to 3 padlocks

  • Shackle diameter 8 mm (3/8")

Benefits of plug-in technology

  • Defective molded case circuit breakers can be replaced quickly and easily

  • Clear visual evidence of safe electrical isolation of main circuits

  • Remote signaling of molded case circuit breaker positions:

    • "INSERTED": The 3VA molded case circuit breaker is properly inserted and bolted to the socket

    • "WITHDRAWN": The bolts have been removed and the 3VA molded case circuit breaker removed

  • Plug-in socket can be locked by padlocks to prevent insertion of a molded case circuit breaker

  • Degree of protection IP20 at all termination points

  • No grounding required

Plug-in contacts for attachment to the main terminals of the 3VA molded case circuit breaker

3VA molded case circuit breaker

Screw-mounted terminal cover for the molded case circuit breaker

Autotrip plunger