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TECHN I CAL DATA
S Y S T EM POWE R S TAR
227
BSEN60439-1 : FORMS OF SEPARATION
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FORMS OF SEPARATION
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As described in BSEN60439-1 the Forms of Separation comprise four
levels as detailed in the above table. The various methods of achieving
separation can involve sleeving the busbars inside a separate box or a
combination of both methods.
COST EFFECTIVE SPECIFICATION
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In order to gain maximum benefit from the standard it is necessary to
consider the application for which the switchboard is required and the
appropriate level of separation for the environment in which it is to be
installed. For example a Form 4 switchboard may be appropriate where
general access is permitted to the switch room but where the
switchboard is in a locked substation with access restricted to qualified
personnel, a lesser degree of separation may be more appropriate.
TYPICAL APPLICATIONS
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Form 1 – No separation
Typical applications are places where the switchboard is in a secure
location and where failure of the switchboard will cause little or no
additional disruption to other areas being fed by the switchboard.
Form 2 – Separation of busbars from functional units.
Applications may well be the same as Form 1 but where it is
important that a fault in the switchboard need not affect all
functional units being fed from the same busbar system.
Form 3 – Separation of busbars from functional units and
the functional units from one another but not
their terminations.
Should be applied where it is important to provide protection from
internal live parts and where failure of functional units being fed
from the same busbar would cause unacceptable disruption.
Form 4 – Separation of busbars from functional units and
the functional units from one another including
their terminations.
Should be applied where it is important to provide protection from
internal live parts and where failure of functional units being fed
from the same busbar would cause unacceptable disruption.
Because all the terminations are separated it is possible to isolate
and work on a single functional unit.
Separation of busbars from
the functional units and
separation of all functional
units from one another
including the terminals for
external conductors which
are an integral part of the
functional unit.
Separation of busbars from
the functional units and
separation of all functional
units from one another.
Separation of the terminals
for external conductors
from the functional units,
but not from each other.
Separation of busbars from
the functional units.
Terminals for external
conductors not separated
from busbars.
Terminals for external
conductors separated
from busbars.
Terminals for external
conductors in the same
compartment as the
associated functional
unit.
Terminals for external
conductors not in the
same compartment as
the associated functional
unit. but in individual,
separate, enclosed
protected spaces or
compartments.
Terminals for external
conductors not separated
from busbars.
Terminals for external
conductors separated
from busbars.
Form 2
Form 3a
Form 3b
Form 4
Type 7 All separation requirements are by metallic or non-metallic
rigid barriers or partitions. The termination for each functional
unit has its own integral glanding facility.
Type 6 All separation requirements are by metallic or non-metallic
rigid barriers or partitions. Cables are glanded in common
cabling chamber(s).
Type 5 Busbar separation is by metallic or non-metallic rigid barriers or
partitions. Terminals may be separated by insulated coverings
and glanded in common cabling chamber(s).
Type 4 Busbar separation is achieved by insulated coverings,
e.g. sleeving, wrapping or coatings Cables may be
glanded elsewhere.
Type 3 All separation requirements are by metallic or non-metallic
rigid barriers or partitions. The termination for each functional
unit has its own integral glanding facility.
Type 2 Busbar separation is by metallic or non-metallic rigid
barriers or partitions. Cables may be glanded elsewhere.
Type 1 Busbar separation is achieved by insulated coverings,
e.g. sleeving, wrapping or coatings Cables may be
glanded elsewhere.
Type 1 Busbar separation is achieved by insulated coverings,
e.g. sleeving, wrapping or coatings
Type 2 Busbar separation is by metallic or non-metallic rigid barriers
or partitions.
Type 1 Busbar separation is achieved by insulated coverings,
e.g. sleeving, wrapping or coatings
Type 2 Busbar separation is by metallic or non-metallic rigid
barriers or partitions.
Form
Form 1
Type of Construction
Sub criteria
Main criteria
No separation
FORMS OF SEPARATION