Saturday, January 25, 2014
Friday, January 24, 2014
Corrosive environment
ISO 12944 Classification Typical Environments
C1 Heated buildings/neutral atmosphere
C2 Rural areas, low pollution
C3 Urban and industrial atmospheres
Moderate sulphur dioxide levels
Production areas with high humidity
C4 Industrial and coastal
Chemical processing plants
C5I Industrial areas with high humidity and
aggressive atmospheres
C5M Marine, offshore*, estuaries, coastal
areas with high salinity
Saturday, January 18, 2014
Enclosure for potentially explosive atmospheres
What is ATEX?
It is a term commonly used to describe potentially explosive atmospheres
(ATmosphères EXplosibles in French) and standards for protection systems
and equipment.
Two European directives, ATEX 99/92/CE and ATEX 94/9/CE, and
international standards IEC 60079 and IEC 61241, harmonized with
EN European standards, apply to this field.
How is an potentially explosive atmosphere defined
according to ATEX?
An potentially explosive atmosphere is defined as a mix of flammable
substances in the form of gas, vapour, dust (cloud or deposit) which, in air
and under normal atmospheric conditions, can completely or partially catch
fire in the form of an explosion when exposed to a source of ignition.
Equipment for potentially explosive atmospheres
Degree of protection In hazardous areas, equipment is required to
offer a minimum degree of protection of IP54, but it can be tested or
certified with a higher degree of protection.The final solution must be certified by a notified body
Since 1st July 2003, European directive ATEX 94/9/CE has made it compulsory to use certified electric or
non-electric equipment when it must be installed in zones with explosive atmospheres (gas or dust).
Certification must be provided by a body which is notified according to the same directive.
The body notifies its assessment of the quality of the production and certifies that the product complies
with the health and safety demands defined in the directive and the international standards.
The certificate shows the category of the product by marking, and thus the zone and atmosphere in
which it can be used.
The standards define the following types of protection for electric equipment:
Enclosures are certified as components. They will be assembled with other ATEX electrical, pneumatic
and hydraulic components, among others to form a final solution which, in turn, must be ATEX-certified
and subject to a declaration of conformity
More info.
http://www.schneiderelectric.pt/documents/product-services/involucros-universais/ATEX.pdf
Thursday, January 16, 2014
Monday, January 13, 2014
ASTA Type Test Certification
ASTA Type Test Certificates provide authoritative objective evidence that your bespoke equipment is compliant to relevant safety standards. The certificate can be used for supporting technical files related to CE Marking for the European Union.
ASTA Type Test Certification is best suited for low volume or ‘bespoke’ equipment. ASTA Type Test Certification provides you with an independent compliance test certificate for one or a number of samples when tested against the requirements of the product safety standard. The document issued is known now as an ‘ASTA Type Test Certificate.’
Type test certification does not involve inspection of the manufacturing facility and the production processes. In some markets type test certification may be sufficient to satisfy the legislative or commercial requirements but in others, particularly where the safety and compliance of mass-produced products is concerned, additional guarantees may be required i.e. full certification. All test reports and certificates are verified by independent Intertek engineers. The ASTA Type Test Certificate issued is sealed and bound to prevent misuse.
Network of Global ASTA Recognized Laboratories
Shipping heavy bespoke equipment to testing laboratories can be a costly exercise. In order to assist our customers, Intertek has a global network of ASTA recognized laboratories. These recognized laboratories may carry out tests to support the issue of ASTA Certificates and Test Reports in accordance with ASTA’s rules and regulations. Mandated ASTA Observers witness the type tests on behalf of ASTA and the ASTA Observers draft the ASTA reports and certificates which are then sent to the ASTA office for verification and issue.
Products for which ASTA Type Test Certificates can be issued include:
| Product | Standard |
| LV Assemblies | IEC 60439-1 / IEC 61439-2 |
| LV Busbar Trunking Systems | IEC 60439-2 |
| LV Distribution Boards | IEC 60439-3 |
| LV Fuses / Fuse holders | IEC 60269 Series |
| LV Circuit Breakers | IEC 60947-2 |
| LV Fuse Switches | IEC 60947-3 |
| LV Starters / Contactors | IEC 60947-4-1 |
| Miniature Circuit Breakers | IEC 60898 |
| Power Transformers | IEC 60076 Series |
| HV Circuit Breakers | IEC 62271-100 |
| HV Metal Enclosed Switchgear & Controlgear | IEC 62271-200 |
| Internal Fault (Arc) Tests | IEC 62271-200 Annex A |
Copyright :
Friday, January 10, 2014
Salt mist test
This test serves to demonstrate that under the influence
of a saline atmosphere no damage (corrosion) is caused
to the components of the equipment under test and no
functional affections occur. This test is only performed
on products which are to be installed on the open deck
area.
Cold & Damp Heat test
Cold
This test serves to demonstrate that under the influence
of cold no damage is caused to the equipment under
test and no permanent or temporary malfunctions occur.
5.1 Test procedure
Basis: IEC publication 60068-2-1
– Test A): for products inside the ship
– Test B): for products on the open deck or in
cold areas.
5.2 Test conditions
The functional tests are performed at the rated operational
voltage Ue.
Damp heat
This test serves to demonstrate that under the influence
of damp heat no damage is caused to the equipment
under test and no permanent or temporary malfunctions
occur.
7.1 Test procedure
Basis: IEC publication 60068-2-30
– Test Db
7.2 Test conditions
The functional tests are performed at the rated operational
voltage Ue.
Tuesday, January 7, 2014
Design verification
Design verification is a prerequisite for all assemblies
provided. It is fundamental to ensuring every assembly
meets its defined design requirements. There is flexibility
in the way in which this is achieved within the new standard,
and some new concepts have been introduced, but the
options are defined and where necessary their use is
restricted and a design margin applied.
Examples of the limitations and margins applied to verification without type test include;
All assemblies connected to a supply with a prospective short circuit current in excess of 10kA
rms or having a cut-off current of 17kA peak must be of a type-tested design or the verification
must be an interpolation from a reference design. Under no circumstances can the assigned
short circuit current rating be higher than that of the reference design.
So as to take account of the air temperature within the enclosure, thermal interactions and
possible hot spots; components within a circuit that has not been temperature rise tested,
must be de-rated to 80% of their free air current rating.
Comparison of the power loss of the components within an assembly with the known heat
dissipation capability of an enclosure, is restricted to assemblies having a rating of 630A.
Confirmation of temperature rise performance by calculation is limited to assemblies with a
rating not exceeding 1600A. Test or interpolation from a tested design must be used to verify
higher ratings.
EMC Environment
Assemblies can emit and the must be immune to external
electromagnetic disturbances. IEC defines two categories
a) Environment A - relates to low-voltage non-public or industrial
networks / locations / installations including highly disturbing sources.
b) Environment B - relates to low-voltage public networks such as
domestic commercial and light industrial locations / installations.
This environment does not cover highly disturbing sources such as
arc welders.
The specifier should detail a requirement for either Environment A or B.
In exceptional applications, for example, some rail applications, it is
necessary to specify a higher level of immunity.
Rated diversity factor
In reality all circuits within an assembly will not be called upon to carry
their rated current simultaneously and continuously. Diversity is the
proportion of their rated current each circuit within a group of outgoing
circuits or all outgoing circuits within the assembly can carry,
continuously and simultaneously, without the assembly overheating. In
the absence of any other information in the assembly specification the
manufacturer will assume the standard diversity factors for the whole
assembly.
Typical RDF
| Number of main |
|
| 2 and 3 | 0.9 |
| 4 and 5 | 0.8 |
| 6 to 9 inclusive | 0.7 |
| 10 and more | 0.6 |
| SCHNEIDER ELECTRIC |
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