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Type
A1 |
For unarmoured cable with an elastomer or
plastics outer sheath, where the function of the gland
is to secure the outer sheath of the cable. |
Type A2 |
As type A1, but with an IP66 seal between the outer
sheath and gland. |
Type B |
For armoured or wire braided cable, where the function
of the gland is to secure the armour or metallic braid
and to provide electrical continuity between such armour
or braid and the threaded fixing component of the gland. |
Type C |
For armoured or wire braided cable with elastomeric
or plastics outer sheath. As type B but with an IP66 seal
between the outer sheath and gland. |
Type E1 |
For armoured or wire braided cable with an extruded
elastomeric or plastics inner sheath and elastomeric or
plastics outer sheath and gland and etween the inner sheath
and threaded fixing component. |
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The suffix for each type of protection shall be as follows. |
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Single
wire armoured |
W |
Pliable
wire armoured flexible |
T |
Wire braided |
X |
|
Aluminium
strip armoured |
Y |
Double
steel tape armoured |
Z |
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Proof torque test
Test one gland of each size and type. The gland shall be clean,
new and without lubricant. Screw the threaded fixing component
of the gland into a suitably tapped hole in a substantial block
of steel.
The thickness of the block shall be greater than the length
of the thread on the component, and the hole pass right through
the block.
Assemble the gland with a short piece of the appropriate kind
of cable of any diameter within the range of the gland.
Tighten the gland with a manually operated torque spanner to
the appropriate proof torque given in tables 1 to 6(BS 6121)
; apply the spanner first to the main body of the gland and
then to each successive hexagonal component.
Dismantle the gland and examine it. Ignore any seal distortion. |
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Load test for type A glands
Test one gland of each size and type. The gland shall
be clean, new and without lubricant. Mount the gland as
shown in figure 1. Secure a cylindrical low carbon steel
mandrel, of the diameter specified in table 1(BS 6121)
and any convenient length, in the gland; do this by tightening
the gland with a torque spanner to a torque equal to 50%
of the proof torque specified in table 1(BS 6121). The
mandrel, which shall be clean, dry and polished, shall
carry a platform on which weights may be placed.
Mark the mandrel so that any movement relative to the
gland can easily be detected. Load the mandrel with weights
until the total tensile load of the mandrel, platform
and weights is in accordance with table 1(BS 6121). Maintain
the load for 6 hrs. Measure at the end of this period,
the distance, if any, through which the mandrel has moved
relative to the gland. |
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Test one insulated adaptor of each size.
Mount the adaptor in a suitable gland plate as shown in
figure 2.
Tighten a suitable gland into the adaptor to enable the
radial torque to be applied. Insert into the gland a mandrel
of appropriate size, ensuring that the mandrel end does
not enter the adaptor. Make arrangements to suspend weights
from the mandrel.
When calculating the radial torque to be applied assume
that the weight of the mandrel itself acts halfway along
its length. Apply the load for not less than 5 min. Finally,
dismantle the assembly and inspect the insulated adaptor
for signs of damage. |
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Flammable mixtures can be classified under two main characteristics
in respect of explosion protection; temperature of ignition
by hot surfaces and the spark energy required to ignite the
mixture. The spark energy of the ignition is also related to
the intensity of the explosion. Classification of maximum surface
temperatures in both North America and Europe are similar but
vary slightly in the nomenclature used. The temperature classification
is important to ensure that the correct equipment is matched
to the flammable atmosphere that could potentially exist in
an area. This will take into account such things as maximum
ambient temperature and maximum operating voltage with a + 10%
over voltage or an overload condition applied. In some types
of protection such as Ex¡® d¡¯or ¡®nR¡¯ the temperature classification
is based on the outside temperature of the enclosure whereas
in other types of protection such as Ex ¡®e¡¯or ¡®nA¡¯the temperature
classification is based on the temperature of the internal components. |
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(Unless otherwise specified on the rating plate it is assumed
that the operating ambient temperature is in the range -20¡£C
to +40¡£C in accordance with European standards) All gases are
grouped according to their physical properties and details of
their grouping can be found in either National or International
codes of practice. Some examples of Gas Groups are shown below. |
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GROUP |
GAS |
I(Mining) |
Methane(firedamp) |
IIA |
Industrial methane, propane, petrol & most industrial
gases. |
IIB |
Ethylene, Town gas & other industrial gases |
IIC |
Hydrogen, Acetylene & Carbon Di-sulphide |
|
|
Ambient Temperature |
|
The ambient temperature is the surrounding temperature of
the environment in which the equipment is installed, whether
indoors or outdoors. For electrical equipment certified in Europe
it is assumed that the ambient temperature in which the equipment
may be operated is between -20¡£C and + 40¡£C. Some types of equipment
are certified for operation outside this range and if so must
be stated on the equipment label or certificate.¡± |
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The ATEX directive (94/9/EC) came into force in April 1994
and was enacted into UK law in March 1996. It became a mandatory
requirement in july 2003. Most of the products in this catalogue
have an EC type examination certificate to the ATEX directive.
ATEX covers both electrical and mechanical ignition hazards.
Apparatus are divided into equipment groups (I for mining and
II non-mining), source of ignition Gas (G) and Dust (D) and
Categories 1, 2 and 3. The categories provide respectively,
very high, high and normal levels of protection against ignition.
The categories deliver the level of protection which is currently
obtained by applying the existing protection techniques (Ex
¡®d¡¯, Ex ¡®e¡¯etc) and they also take into account other protection
concepts proposed by manufacturers and considered by the notified
(certification) bodies who produce EC type examination (ATEX)
Certificates.
The categories in practice are equated to suitability for Zones.
The actual category of apparatus specified for a Zone depends
on the overall risk assessment for a Zone. The zoning considers
only the probability of the existence of an explosive atmosphere.
It does not consider the consequential effects of an ignition
taking place. Apparatus are marked with the grouping and category
in addition to the marking required by the individual protection
standards. |
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 |
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Although this code change permits the use
of products that have a Zonal classification, in a similar
way to European practice, mixing of different forms of
equipment approval across zones or divisions is not acceptable.
e. g. products approved for Zone 1 do not necessarily
meet the requirements of Division 1, which also encompasses
Zone 0.
Although no direct equivalents exist between European/IEC
and American codes of protection and Area Classification
there are similarities and there is a developing acceptance
of European/lEC methods in North America and vice versa
The following table shows the basic relationships between
the North American and European classifications. |
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Flammable
gas
always present
> 1000 hrs/year |
Flammable
gas
normally present
> 10 -1000 hrs/year |
Flammable
gas not
normally present
< 10 hrs/year |
CENELEC/IEC |
Zone 0
(Zone 20 dust) |
Zone 1
(Zone 21 dust) |
Zone 2
(Zone 22 dust) |
ATEX |
Category 1G
Category 1D |
Category 2G
Category 2D |
Category 3G
Category 3D |
US-NEC 505 |
Zone 0 |
Zone 1 |
Zone 2 |
US-NEC 500 |
Division 1 |
Division 1 |
Division 2 |
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As can be seen from the table above, Division I covers both
the European/IEC Zones 0 & 1. Therefore, care must be taken
when using zone classified equipment in a Division1 area as
to the suitability of the protection employed.
Underwriters¡¯ Labortory (UL) and Factory Mutual Inc(FM) are
two main certification bodies in North America and in some cases,
electrical equipment may also need to meet certain Marine Standards,
and be separately approved by the US Coast Guards, before it
can be used e. g. on an offshore oil rig. |
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Method of
Protection |
Symbol |
Permitted
Zone |
ATEX
Category |
CENELEC
Standard |
IEC
Standard |
Protection
Principle |
Flameproof |
Ex d |
1 & 2 |
2 & 3 |
EN50018 |
79-1 |
Contain the explosion
and prevent transmission |
Enclosed Break |
Ex nC |
2 |
3 |
EN50021 |
79-15 |
Powder Filled |
Ex q |
1 & 2 |
2 & 3 |
EN50017 |
79-5 |
Increased Safety |
Ex e |
1 & 2 |
2 & 3 |
EN50019 |
79-7 |
No Arcs, sparks of hot
surfaces or components |
Non Sparking |
Ex nA |
2 |
3 |
EN50021 |
79-15 |
Intrinsic Safety |
Ex ia |
0,1 & 2 |
1,2 & 3 |
EN50020 |
79-11 |
Limit energy of sparks and
limit temperature of hot
surfaces or components |
Ex ib |
1 & 2 |
2 & 3 |
EN50020 |
79-11 |
Energy Limitation |
Ex nL |
2 |
3 |
EN50021 |
79-15 |
Pressurised |
Ex p |
1 & 2 |
2 & 3 |
EN50016 |
79-2 |
Prevent flammable gas
coming into contact with
hot surfaces and ignition
capable equipment |
Encapsulation |
Ex m |
1 & 2 |
2 & 3 |
EN50028 |
79-18 |
Oil lmmersion |
Ex o |
1 & 2 |
2 & 3 |
EN50015 |
79-6 |
Restricted Breathing |
Ex nR |
2 |
3 |
EN50021 |
79-15 |
Special |
Ex s |
0,1 & 2 |
1,2 & 3 |
EHSR |
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Any proven method |
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A major secondary protection parameter is the ingress protection
of the electrical equipment. Moisture or dust if allowed to
come into contact with electrical circuits could lead to either
sparking or physical breakdown of the components and interfere
with the protection method being used. In some cases the IP
ratings for products in this catalogue have been carried out
in accordance with EN 60529 (IEC 529) and have been witness
tested by independent test laboratories. It will be noted that
some products have both IP66 and IP67 ratings and this is because
in some instances the IP66 requirment is more onerous than the
IP67 requirement. Both the SX range and BPG range have also
been tested to the Shell/ERA deluge specification. This is one
of the most onerous water ingress tests and we designed specifically
for electrical equipment which would be subject to deluge conditions,
e.g. Ships decks, fire deluge areas. The following table shows
the criterion for IP requirement to EN60529(IEC 529). |
|
|
First
Digit |
Degree
of Protection |
0 |
|
No protection |
1 |
 |
Protection against ingress
of large solid particles |
2 |
 |
Protection against ingress
of medium sized solid particles |
3 |
 |
Protection against ingress
of medium solid particles greater
in thickness than 2.5mm |
4 |
 |
Protection against ingress of small
solid foreign bodies greater in
thickness than 1mm |
5 |
 |
Protection against ingress of dust
in an amount sufficient to interfere
with enclosed equipment. |
6 |
 |
Complete protection against
ingress of dust. |
|
Second
Digit |
Degree
of Protection |
0 |
|
No protection |
1 |
 |
Protection against ingress
of vertically dripping water |
2 |
 |
Protection against ingress of water
dripping at an angle of 75¡£to 90¡£ |
3 |
 |
Protection against ingress of
sprayed water |
4 |
 |
Protection against ingress of
splashed water |
5 |
 |
Protection against ingress of
water jets |
6 |
 |
Protection against ingress ofwater in heavy water |
7 |
 |
Protection against effects
of temporary immersion |
8 |
 |
Protection against effects
of indefinite immersion |
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The IECEx is a single global certification framework to facilitate
international trade in equipment and services for use in explosive
atmosphere based on the IEC (International Electrotechnical
Commission)¡¯s international standard while maintaining the required
level of safety : |
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* Reduced testing and certification costs to manufacturer
* Reduced time to market
* International confidence in the product assessment process
* One international database listing |
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The goal is to help manufacturers reduce costs and time while
developing and maintaining uniform product evaluation to protect
users against products that are not in line with the required
level of safety. So it should help industry to open up new markets
from different conformity assessment criteria in various countries.The
aim of the IECEx Scheme and its programs is to ease international
trade of explosion protected equipment (termed Ex equipment)
by eliminating the need for duplication of testing and certification
while preserving safety. |
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IECEx accepts the participation of Ex certification bodies
and Ex test laboratories only after successful completion for
the IECEx Assessment Process which also includes on-going surveillance
each Ex candidate certification body and testing laboratory
are subjected to the same IECEx assessment process utilizing
the internationally established ISO/IEC standards and guides
on conformity assessment supplemented with the IECEx technical
guidance documents with world experts in the field of explosion-protection
being appointed as IECEx Assessors. |
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 |
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IEC (Marking : Ex d IIB T4)
(EEx d IIB T4 : CENELEC Standard / Class, Zone 1, AEx d IIB
T4 : American Standard (NEC 505) |
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Type of Enclosure |
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There are many factors to consider when selecting cable glands
for industrial installations. Neglecting to pay due attention
to some of these factors may cause unnecessary anxiety at a
future point in time when the equiment and cable have either
been forgotten to be ordered or it is discovered that they are
the incorrect type or size at the very point when they are needed
the most. |
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Good advice would be to allocate some value added planning
and preparation time to the subject of cable gland selection
so as to avoid the great inconvenience which is likely to occur
at a critical point in time. In the event that a user or contractor
is in possession of a cable schedule that requires a cable gland
selection and sizing process to be carried out, OSCG would be
more than happy to assist in carrying out this process at no
cost to the enquirer. |
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Please contact OSCG for further information on this subject. |
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Here is a summary of some aspects to carefully consider when
selecting cable glands.
¡á Identify the type of cable to be used.
¡á Check the construction, size & material properties of
the cable. |
|
When the cable is armoured, verify the following
¡á Check the type and material of the cable armour
¡á Check the short circuit fault current rating of the cable
armour
¡á Check the actual diameter of the inner bedding(where present)
against this catalogue.
¡á Check the actual diameter of the lead covering(where present)
against this catalogue.
¡á Check the actual size of the overall cable cable diameter
against this catalogue.
¡á Check the size and type of armour or braid against this catalogue.
¡á Check any special environmental requirements in relation to
corrosion protection.
¡á Check the material of the mating electrical enclosures to
eliminate dissimiar metals.
¡á Consider whether any protective plating is required to be
applied to the cable gland.
¡á Check the type and size of the cable entry hole in the mating
electrical equipment.
¡á Check the ingress protection rating of the electrical equipment
or site standard.
¡á Check whether a single seal or double seal cable gland is
required.
¡á Check whether an entry thread seal is required for IP66(or
IP67/68) conditions.
¡á Check whether fixing accessories such as lock nuts and serrated
washers are required.
¡á Check whether earth tags are required.
¡á Check whether shrouds are required.
¡á Select a corresponding cable gland type from this catalogue.
¡á For installation in hazardous areas, special considerations
should be taken into account to ensure compliance
with national or make the installation.
¡á Select corresponding adaptors or reducers from this catalogue.
¡á Check whether any stopping plugs are required to close unused
cable entries.
¡á Select corresponding stopping plugs from this catalogue. |
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