1. What about type tested assemblies?
The tested switchboard, complying with IEC 1

2. IEC standards are based on the
consensus and knowledge find among the best experts in the world.
They provide minimum requirements and test procedures for safe and reliable installation allowing a high availability of the electrical energy

3. What is a switchboard used for ?
To gather and protect the control and protective devices together with electrical and mechanical connections against external influences.
To inform the end-user on the state of his installation.
To protect the switchboard user against the main risk of accidents (direct contact protection, indirect contact protection and fire risk).
To evolve with the activity
Présence d’une Animation
Installations monitoring
and control
Protection for individuals
Electrical power distribution

4. The LV electrical switchboard has to be safe and available
It is a question of balance between:
the needs of safety and availability
the constraints of reliability and maintenability of the installation.
Safety
Maintenability
Reliability
Availability
Présence d’une Video

5. Low-voltage switchgear and controlgear assemblies
IEC series
Low-voltage switchgear and controlgear assemblies
One general standard :
IEC type-tested assemblies (TTA) and partially type-tested assemblies (PTTA)
Four related standards:
IEC busbar trunking systems (busways)
IEC distribution boards (<250A, unskill people)
IEC assemblies for construction sites (ACSs)
IEC cable distribution cabinets (CDCs)

6. What about the main features?
The tested switchboard, complying with IEC 1

7. IEC 60439-1, what about the scope?
Scope : Low-voltage switchgear and controlgear assembly, TTA or PTTA, whose rated voltage is  1000 Vac or 1500 Vdc.
TTA : type-tested assemblies conforming to an established type or system without deviations likely to significantly influence the performance, from the typical ASSEMBLY verified to be in accordance with this standard. A full range of representative configurations have been tested.
PTTA : partially type-tested assemblies, containing both type-tested and non type-tested arrangements provided that the latter are derived (e.g. by calculation) from type-tested arrangements which have complied with the relevant tests. Some limited configurations may be tested.
Definition : A combination of one or more low-voltage switching devices together with associated control, measuring, signalling, protective, regulating equipment, etc., completely assembled under the responsibility of the manufacturer with all the internal electrical and mechanical interconnections and structural parts
Either a TTA or a PTTA equipment meeting IEC afford the same quality level

8. The IEC 60439-1 standard gives general rules for switchboards construction
Meeting IEC requirements means :
a minimum level of safety for people and equipment
to include the low-voltage switchgear and controlgear assemblies for the power distribution and control
precise requirements for
- service conditions (temperature...)
- construction requirements (IP, IK, forms,...)
precise test procedures
IEC : one worldwide standard for all the professionals of switchboards.
Safety
Maintenability
Reliability
Availability
Conformity to IEC provides
an insurance on switchboard realization quality

9. Classification according to IEC 60439-1
external design (open-type, dead front, enclosed, busway)
place of installation (indoor - outdoor)
conditions of installation with respect to mobility (stationary - movable)
degree of protection (for outdoor IP 3X)
type of enclosure (e.g metallic or plastic)
method of mounting (fixed or removable)
measures of protection of persons
form of internal separation (to be detailed, agreement between customer and manufacturer)
types of electrical connections of functional units (to be detailed, agreement between customer and manufacturer)

10. IEC 60439-1 : Functional unit Functional unit
Definition : Part of an assembly, comprising all the electrical and mechanical elements that contribute to the fulfilment of the same function
Example : drawer in a Motor Control Centre switchboard .
Incoming
Outgoing
Auxiliary
Functional unit

11. IEC 60439-1 proposes different type of secured forms adapted to each situation
V. Forms
In most installations, no particular partitioning is needed, electrical switchboard of the form 1 type is acceptable.
However this is no longer true without a front plate or other equivalent mean. The user shall not access to living parts.
Following forms 2, 3 and 4 introduce additional partitioning within the switchboard
Form 2: partitioning of busbars
Form 3a and 3b:
functional units separated from each other and separated from the busbars
connecting terminals separated from busbars
Form 4a and 4b:
connecting terminals separated from each other and separated from busbars.

12. IEC 60439-1 The forms of internal separation
Form 2a
Form 3a
Form 4a
Form 2b
Form 3b
Form 4b
1. Maintenance people should not be in a dangerous situation, e.g. parts not under maintenance should not create dangerous situation in parts under maintenance
2. Maintenance in one part should not create a dangerous situation in another part e.g. a screw or a tool falls in another part
3. Danger in one part should not expand to other parts e.g. an arc in one part should not influence other parts

13. Electrical connections for functional unitsB
Types of electrical connections of functional units (FU)
F = Fixed
D = Disconnectable
W = Withdrawable
Identification
connections are codified with these 3 letters referring to :
1st : main incoming circuit
2nd : main outgoing circuit
3rd: auxiliary circuits

14. What about test procedure ?
The tested switchboard, complying with IEC 1

15. The tests of standard IEC 60439-1B
They guarantee that the switchboard complies with the necessary standard requirement
There are two type of tests:
7 type tests are performed by the manufacturer on one or several configurations:
n°1 temperature rise limits
n°2 dielectric properties
n°3 short-circuit withstand
n°4 protective circuit effectiveness
n°5 clearances and creepage distances
n°6 mechanical operation
n°7 degree of protection.
3 routine tests are performed by the panelbuilder on each particular switchboard:
n°8 general inspection
n°9 insulation/dielectric test
n°10 protection measures.

16. The 7 type tests performed by the manufacturer
The aim of these tests is to confirm the switchboard
characteristics.
The 7 type tests are carried out on the most difficult and unfavourable system configurations. The assembled and cabled switchboards are made up of their usual components, connection system…, equipped with switchgear and assemblied and installed according to industrial standards.
The tests are conducted either in approved laboratories (Asefa, Kema, Lcie,…), or in a manufacturer laboratory.

17. (8-2-1): temperature rise limits
Test n°1
(8-2-1): temperature rise limits
Test performed by the manufacturer
Guarantees the safety and reliability of the switchboard, by avoiding problems such as:
connection damages
reduction in insulation performances
risk of burn for maintenance operators
electronic components damages
faulty operation of the devices: inopportune release.
How to proceed:
to measure the temperature of each equipment, after a delay allowing a stabilized temperature, when each circuit is used at its rated power and when the complete switchboard is loaded with an appropriate diversity factor
Result to be obtain
temperature rise shall not exceed what the different equipment can withstand
the temperature of accessible surfaces has to be checked

18. (8-2-2): dielectric properties
Test n°2
(8-2-2): dielectric properties
Test performed by the manufacturer
Guarantees the switchboard safety and reliability, to avoid problems such as:
electrical arc generation
insulation performance decreasing
connection damages
Withstand impulse voltage test and an ac test are performed

19. (8-2-3): short-circuit withstand
Test n°3
(8-2-3): short-circuit withstand
Test performed by the manufacturer
This test simulates an incident which could occur on site.
Withstanding the short-circuit currents is:
to avoid danger (rupture and projections of components, arc generation and propagation outside the switchboard,...)
it also means the installation can be quickly put back into operation after the incident.
Relationship between peak current (Ipk) and short-circuit current (Icw):
Ipk = Icw x n
RMS value of short-circuit current kA eff/1s (Icw) n
Ipk (kA)
Icw £ 5
1.5
Ipk £ 7.5
5 < Icw £ 10
1.7
8.5 < Ipk £ 17
10 < Icw £ 20 2
20 < Ipk £ 40
20 < Icw £ 50
2.1
42 < Ipk £ 105
50 < Icw
2.2
110 < Ipk

20. (8-2-4): effectiveness of the protective circuit
Test n°4
(8-2-4): effectiveness of the protective circuit
Test performed by the manufacturer
The effectiveness of the protective circuit is verified by two tests:
resistance measurement of the connection between the exposed conductive parts and the protective circuits
short-circuit withstand performed between the protective conductor and the nearest phase conductor.

21. (8-2-5): clearance and creepage distances
Test n°5
(8-2-5): clearance and creepage distances
Test performed by the manufacturer
Clearance control: shortest distance between two conductive parts.
Creepage distance control: shortest distance along the surface of an insulating material between two conductive parts.

22. (8-2-6): mechanical operation
Test n°6
(8-2-6): mechanical operation
Test performed by the manufacturer
Endurance of material, guaranteeing the longevity of the various mechanisms.
The standard requires 50 operating cycles.

23. (8-2-7): degree of protection (IP, IEC 60529)
Test n°7
(8-2-7): degree of protection (IP, IEC 60529)
Test performed by the manufacturer
The tests carried out define the capacity of an equipped switchboard to:
protect persons against contact with live parts
protect equipment against penetration of solid objects and liquids IP
1st digit:
protection of persons
protection against solids.
2nd digit: protection against liquids.
Note: in case of only protection of persons is needed, the 2 IP digits are replaced by x.
Example: IPxxB.
Additional letter (optional): protection of persons against contact with live parts:
A: protect againts access of the back of the hand
B: protect against access of fingers Ø 12 mm
C: protect against access of a tool Ø 2.5 mm
D: protect against access of a tool Ø 0.1 mm.

24. The 3 tests performed by the panelbuilder
These 3 routine tests can be easily and rapidly performed by the panelbuilder:
overall inspection according to the mounting instructions and technical documents (right device ratings, tightening torques)
insulation checking by a dielectric test
checking of protective measures and of the electrical continuity of the protective circuits.
They complete the 7 manufacturer type tests and guarantee professionnalism and responsability of panelbuilder.
3 routine tests performed by the panelbuilder:
n°8 general inspection
n°9 insulation/dielectric test
n°10 protection measures.

25. (8-3-1): general inspection
Test n°8
(8-3-1): general inspection
Test performed by the panelbuilder
Check of mechanical actuating elements, interlocks,... effectiveness.
Check of proper laying of conductors and cables and proper mounting of device.
Check of connections adequate contact, especially screwed and bolted connections.

26. (8-3-4): insulation resistance/(8-3-2): dielectric test
Test n°9
(8-3-4): insulation resistance/(8-3-2): dielectric test
Test performed by the panelbuilder
No arc flash-over or insulator perforation must be observed between the live parts each other and between the live parts and the conductive structural parts.

27. (8-3-3): protective measures
Test n°10
(8-3-3): protective measures
Test performed by the panelbuilder
Checking of protective measures and of the electrical continuity of the protective circuits for metallic assemblies.

28. What about the benefits?
The tested switchboard, complying with IEC 1

29. The benefits from IEC
IEC provides minimum requirements and test procedures for safe and reliable installation allowing a high availability of the electrical energy
Specifiers/consultants:
the certainty to prescribe a switchboard which ensures the level of safety required by the user
Panel-builder / Installer:
confidence in products and swichboards systems, following the standard
increase efficiency, easy to show conformity
Manufacturer:
products tested in real configurations
detailed instructions for fautless construction.