Form 4 Requirements

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Form 4 covers overall assemblies which are so enclosed as to provide protection against contact with internal live parts and components, and in which there is internal separation of the busbar system from functional units, and separation of all functional units from each other. Incoming and outgoing are also required to be separated from the busbars and from each other.

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The following general conditions apply: 1 Busbars are separated from functional units 2 Functional units are separated from functional units 3 Terminations to functional units are separated from each other.

Compliance with any of the requirements of Form 4 may be offered by EIEMA manufacturers by any of the following seven methods. Specifiers and users should clearly indicate their preference.

 

Types of Segregation FRONT ACCESS

The Front Access Cable termination, are as they say facilitated from the front of the panel through a cable way, with the device layout as shown in the top left diagram. They are all Form 4, and can be top or bottom entry, with three different types of segregation.

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Form 4 Type 2 The cables are glanded into the top/bottom of a cable way gland plate, and are then connect directly onto the device terminals, through a clearance hole within a segregation plate. Extension coppers allow metering options.

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Form 4 Type 5 The cables are glanded as above in type 2 into the top/bottom of a cable way gland plate, but the tails are now connect onto extension coppers which protrude into the cable way, shrouded and insulated, allowing larger size cables to be terminated, taking mechanical load off the device and giving a higher degree of segregation.

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Form 4 Type 6 The cables are glanded as above in type 2 & 5 in the top/bottom of a cable way gland plate, but the tails connect onto extension coppers within a Cable Box in the cable way, through a clearance hole within a segregation plate on the box, and insulated, again allowing larger size cables to be terminated, taking mechanical load off the device and giving a higher degree of segregation.

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Types of Segregation REAR ACCESS

The Rear Access Cable termination, are from the rear of the panel through a cable way, with the device layout as shown in the Bottom left diagram. They are all Form 4, and can be top or bottom entry, with only two different types of segregation.

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Form 4 Type 5, Glanding is done in the cable way top/bottom, and the tails are now connect onto extension coppers which protrude into the cable way, shrouded and insulated.

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Form 4 Type 6, Glanding is the same, the tails are now connected onto extension coppers within a Cable Box in the cable way, through a clearance hole within a segregation plate on the box, and insulated