module 09_cable glands september 2007

7/28/2019 Module 09_Cable Glands September 2007

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September 2007 copyright Epsilon Compliance 2007 Compex module 9 cable glands 1

Cable Glands


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What is a cable gland?

A device designed to permit the entry of a cable

into electrical equipment and which providessealing and retention. It may also provide otherfunctions such as earthing, bonding, insulation,

strain relief or a combination of these.


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STEEL WIRE ARMOURED CABLE GLAND

Entry Thread: normally 10mm thread(15mm thread on Ex equipment)

GLAND BODY

COMPRESSION GLAND


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GLAND BODY ARMOUR LOCKING RING

TAPERED CONE

Entry Thread

COMPRESSION GLAND


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TAPERED CONE

Entry Thread

COMPRESSION GLAND


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TAPERED CONE

Entry Thread


COMPRESSION GLAND


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TAPERED CONE

Entry Thread

OUTERSEAL


COMPRESSION GLAND

BACK NUT


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TAPERED CONE


OUTERSEAL

Entry Thread

COMPRESSION GLAND

CONSTRUCTION OF STEEL WIRE ARMOURED CABLE GLAND

BACK NUT


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TAPERED CONE


OUTERSEAL

Entry Thread

COMPRESSION GLAND

BACK NUT


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OUTERSEAL

GLAND BODY

Entry Thread

COMPRESSION GLAND

BACK NUT


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Entry Thread

GLAND BODY

COMPRESSION GLAND


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Cable glands are designed, manufactured and

tested to meet the stringent standards laid downby British and International authorities.

Glands can be approved for hazardous arealocations.


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Standards

All metric glands are designed to BS EN

50262:1999 Imperial glands are designed to BS 6121Part1:2002 (UK)

BS 6121-5: 2005 Code of Practice, selection,installation and inspection of cable glands


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MICC glands designed to EN 60702

EEx e seals meet the requirement of EN 60079-0.

Glands are normally certified as components and

must meet the relevant requirements of theappropriate construction standard

EN 60079-1 for EEx d

EN 60079-7for EEx e


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Cable Glands

There are various types of cable glands from the

simple A type gland right through to thesuperior explosion proof barrier gland kit.

This presentation looks at the different types ofglands plus the accessories for the glands


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Types of Glands A1For unarmoured cable, no outer seal IP4x


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Gland Types

Type A1. For unarmoured cable with an

elastomeric or plastic outer sheath, where thefunction of the gland is to secure the outersheath of the cable.

Type A3. As type A1, but with an electrical bondfor the metallic inner sheath.


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Types of Glands A2For unarmoured cable, outer seal IP66


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Type A2. As type A1, but with an IP66 seal

between the outer sheath and gland. Type A4. As type A2, but with an electrical bond

for the metallic inner sheath.

A* Gland Types


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A2 Gland


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Types of Gland BFor armoured or braided cable, no seals IP30


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Type B. For armoured or wire braid cable,

where the function of the gland is to secure thearmour or metallic braid and to provide electricalcontinuity between such armour or braid and the

threaded fixing component of the gland.

Gland Types


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Types of Gland CFor armoured or braided cables, outer seal IP66


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Type C. For armoured or wire braid cable with

elastomeric or plastic outer sheath. As type B,but with an IP66 seal between outer sheath andgland.

This is the most common non-certified industrialgland

Gland Types


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Types of Gland DFor armoured or braided cables, inner seal IP66


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Type D1. For armoured or wire braid cable with

elastomeric or plastic outer sheath. As type B,but with an IP66 seal between inner sheath andthreaded fixing component.

Type D2. As type D1, but with an electrical bondfor the metallic inner sheath.

Gland Types


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Types of Gland EFor armoured or braided cables, inner and outer seal IP66


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Type E1. For armoured or wire braid cable with

an extruded elastomeric or plastics inner sheathand elastomeric or plastics outer sheath. As typeB, but with an IP66 seal between inner sheathand gland and between the inner sheath and

threaded fixing component. Type E2. As type E1, but with an electrical bond

for the metallic inner sheath.

Gland Types


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Glands of type B, C, D1, E1 and E2 which are

suitable for armoured or wire braid are alsoidentified by a suffix, added to the designation,to indicate the type of protection for which the

gland is suitable.


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Steel wire armoured W Pliable wire armoured flexible T

Wire braided X

Aluminium strip armoured Y

Tape armour Z

Suffix Letter BS 6121


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Construction

All glands used for armoured or braided cables

have an armour-locking ring with the exceptionof the BW. The armour wires are trappedbetween a locking ring and the armour cone ofthe threaded fixing component by the action of

screwing the gland body to the hub. This ALR will continue to trap the armour wires

even if the gland body became loose through

heat cycling, vibration or during maintenance.The earth continuity can be electrically testedand visually inspected after installation.


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For use with threaded or clearance holes (IP54) tomaintain IP66 a sealing washer is used.

Sealing Washers


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IP Rating

To maintain IP66 between equipment and cablegland, the use of a nylon/fibre entry seal is

recommended. A threaded joint sealed with a suitable setting

compound will maintain IP66. Care should betaken however, to preserve any electricalcontinuity requirement. With this in mind, glandsin conjunction with good quality enclosures (atleast 6mm thick) will attain the following IP rating

without additional materials. Screwed entry-IP54


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Sealing washers

Improves IP rating between the gland and theequipment. Red Fibre or white nylon availableaccording to customer preference.


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Earth Tags

Used to maintain

earth continuityvarious sizesavailable.


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Earth Tags

For clearance holes entry situations, it isessential to obtain direct metal to metal contactbetween the gland, earth tag (if used) and theenclosure. For situations when earth short circuitprotective equipment demands positive earthconnections leaving minimum armour to earthimpedance, a range of integral earth glands areavailable.


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Ensures earth continuity is maintained between

the gland and equipment. Earth tags are notrequired on metal boxes, but if they are fittedthey must be bonded together with earth cable

(green/yellow cable).

Earth Tags


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Adaptors and Reducers

Adaptor change the

thread type

Reducer-changes thethread size

One adaptor/reducerper cable entry


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Marking of reducer


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Marking of adaptor


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Adaptors and Reducers

Reducers enable a gland with smaller thread

size to be installed in larger thread opening. Adaptors enable a larger or equivalent gland tobe installed in an opening with a smaller threadform. Reducers and adaptors with alternative

thread combinations are available such as: NPT, Pg, BSP and Metric


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Name of Manufacturer

Type e.g. E1WF

Protection concept e.g. EEx d IIC/EEx e II

Size e.g.20s

ATEX mark II 2 GD

IP rating e.g. IP66

Certificate no. e.g. 01ATEX2070X

Marking


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IP rating

Minimum IP rating for cable glands are:

Gas/Vapours minimum is IP54

Dust minimum is IP64


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Barrier Glands

Barrier glands may be required when direct

entry into an Ex d enclosure is required. A filler(compound) is used to consolidate the cores tominimise the effect of explosion pressure, heat

and flame.

The use of barrier glands is generally advised in

the following circumstances:-


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`

EEx d Cable

Selectorchart


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When cables directly enter Flameproof Type dequipment and;

cable used is not round, extruded bedded andsuitably filled

The enclosure contains an internal ignition

source, is approved for Zone 1 use and theinternal free volume exceeds 2 litres. There is a risk of gas migration via the cable

from a hazardous area to a safe area, or in

transition of zones. used in IIC environment


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Glands must be certified, Certified gland will bemarked according to the certificate

Thread preferably metric pitch 1.5mm. Threadedentry minimum of 6 full threads

At least 5 full threads of the gland to be engaged

Thread length of glands are normally 15mm.

Where Intrinsically safe circuits involve cablesentering an EEx d enclosure appropriate EEx dglands must be used, even a barrier gland ifnecessary


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Barrier Gland


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Compound or Barrier gland

Compound

The use of the correct gland is negated if the gland is

either incorrect for the cable or made off incorrectly.Also the thread on the gland must match the thread onthe apparatus.

C d B i l d


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Compound or Barrier gland

The setting timeis normally 4hours the glandmust not be

disturbed duringthis time,


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Barrier gland braided cable


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Barrier Glands

Used with EEx d equipment and also certaintypes of cable.

Additional components to provide a pressuretight seal between the inside of the enclosureand the interstices of the cable.

Different methods may be used to ensure thatthe filler is well compacted around theconductors over the required distance.

Setting time of the compound will depend on a

number of factors ambient temperature, age ofthe compound etc.


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MICC Cable Glands

MICC (Mineral Insulated Copper Conductor)may be used in most situations.

Standard pots maybe used with EEx d, p and n

equipment For EEx e equipment only EEx e pots maybe

used- this is to meet the required wider

clearances.


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Dual certified glands

Most manufacturers of cable glands, over thelast few years, have developed a dual certifiedgland.

Certified as both EEx d and EEx e.

This removes the confusion on what type ofgland to use in any particular circumstance.


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Ex d/Ex e gland


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EEx e Glands Certified gland will be marked according to the

certificate.

A lock nut and seal washer are required when less

than 5 threads are engaged or gland is used in aclearance hole.

A star washer can be used to maintain earthcontinuity

Armouring must be clamped

Earth tag (if required) to be fitted between glandbody and seal washer.


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EEx e glands

Amouring must be clamped

Earth tag (if required) to be fitted between glandbody and seal washer.

However it is prudent to use the appropriate gland

for the protection concept being used. e.g. useEEx e glands or dual certified glands on Ex eequipment.


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EEx n

Glands for use in zone

2 with EEx n apparatusdo not require to becertified, a standardindustrial gland issuitable.

Must maintain IP54


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Gland Body Material

Normally Brass.

Nickel and chromium plate glands are availablefor corrosive atmospheres

Aluminium is not preferred for EEx d flameproofglands due to chemical interaction between

aluminium and rust.Locknuts can be brass or mild steel.

In outdoor environments it is better to use brass,

ensures better earth continuity, better resistant tocorrosion.


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Cable Glands EEx d

IncorrectCorrect

Sealing

Washer

Less than 5 threads fully

engaged.


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Blanking Plugs

Ex e


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Marking of blanking plug

Blanking Pl gs


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Blanking Plugs

Ex d

Shrouds


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Shrouds

PCP or PVC

Used to achieve IP66or IP67 or IP68, onlyas good as standard

of installation

Locknuts


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Locknuts

Two types

Mild steel

Brass

Cold Flow


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Cold Flow

"Cold flow" can be more fully described asthermoplastic materials which flow when

subjected to pressure at ambient temperature,i.e. the inner sheath bedding material will flowaway from any pressure applied to it, includingthat of a cable gland inner seal of the

compression or displacement type, the effectbeing that there may no longer be an effectiveseal on the inner sheath of the cable.

Summary


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Summary

Ex d enclosures use Ex d glands

Ex e enclosures use Ex e glands Determine whether the enclosure is direct or

indirect entry

On Ex d enclosures free volume is important. Consider cable type e.g. braided, Steel wired

armoured etc.

Maintain IP rating of enclosure


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End of Section

module 09_cable glands september 2007

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