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781 | Breather / Drain Plug Available in brass, nickel plated brass, aluminium, stainless steel & nylon

781 Breather Plug & Drain Plugs Breather Plug & Drain Plugs, Globally Approved, Explosive Atmosphere Cable / Conduit Accessory

• 781E for Ex e use
• 781D for Ex d use
• Drains equipment susceptible to moisture collection
• Enables equipment to breathe
• General purpose / industrial version available
• Nylon Ex e only version available (-20°C to +60°C)
• -60°C to 130°C (metallic versions)
• Globally marked, IECEx, ATEX & cCSAus

HOW TO ORDER A guide on how to order Breather Plug & Drain Plugs from CMP: e.g. 781 – D – M – 3 = Ex d – M25 e.g. 781 – E – M – 3 = Ex e – M25 Other Thread Variations are available on request. For further information on ordering please refer to how to order. The CMP 781E range of Increased Safety type ‘e’ breather plug / drain plugs have been tested together with CMP serrated washers to ensure that in areas that are subject to vibration, the breather plug / drain plugs do not suffer from self-loosening and in advertently fall out of the enclosure. Serrated washers are not included as standard but can be ordered separately.

Design Specification BS 6121:Part 1:1989, IEC 62444, EN 62444
Enclosure Protection IK10 to IEC 62262 (20 joules) Brass & Stainless Steel Only
ATEX Certificate CML 18ATEX1330U
Code of Protection 781D: II 2G Ex db IIC Gb, II 1D Ex ta IIIC Da
781E: II 2G Ex eb IIC Gb, II 1D Ex ta IIIC Da
Compliance Standards EN 60079-0,1,7,31
IECEx Certificate IECEx CML 18.0187U
Code of Protection 781D: Ex db IIC Gb, Ex ta IIIC Da
781E: Ex eb IIC Gb, Ex ta IIIC Da
Compliance Standards IEC 60079-0,1,7,31
cCSAus Certificate 1055233
Code of Protection 781D: Ex d IIC, Class I, Zone 1 AEx d IIC; Class I Div 1, Groups A,B,C,D
IP66, Enclosure Type 4X
781E: Ex e II, Class I, Zone 1, AEx e II
IP66, Enclosure Type 4X
Compliance Standards CSA C22.2 No 0-10, 0.5, 30, 94; e 60079-0,1,7, E61241-1-1, UL50, 1203, UL60079-0,1,7
UL Certificate E253914
Code of Protection 781D: Class I, Zone 1 AEx d IIB; Zone 20 AEx ta IIIC
781E: Class I, Zone 1, AEx e IIC;
EAC Certificate (Formerly GOST R, K & B) TC RU C-GB.AA87.B.00487
GOST R Certificate POCC.GB.35.H00102
CCOE / PESO (India) Certificate P444949
INMETRO Certificate TÜV 12.133OU
NEPSI Certificate GYJ18.1248U
RETIE Approval 03866
KCS Certificate 19_AV4BO-0254X


UkrSEPRO CU 19.0370X
Marine Approvals LRS: 01/00173
Continuous Operating Temperature 781D: -60°C to +130°C
781E: -60°C to +130°C (-20°C to +60°C Nylon)
Ingress Protection Rating ** 781D: IP66 (when fitted with CMP sealing accessories)
781E: IP66
Available Materials Brass, Nickel Plated Brass, Aluminium, Stainless Steel, Nylon (781E only)
Accessories Included (781E only) Integral Entry Thread equipment interface ‘O’ ring seal, Castellated Locknut

The 781D can be used with enclosures up to 30 litres for group IIB gases and enclosures up to 2.5 litres for group IIC gases
** When CMP installation accessories are used (781E). Refer to Maintaining a Seal for further information.

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Product Selection Table

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Ordering Reference
Ordering Reference
Thread SizeMinimum Thread LengthProtrusion Length 'F'Across Flats DimensionAcross Corners DimensionsMax Installation Torque (Nm)
781DM2781EM2M20 x 1.50.590.501.181.307
781DM3781EM3M25 x 1.50.590.501.421.5610
781DT1781ET1½' NPT0.780.501.181.307
781DT2781ET2¾' NPT0.800.501.421.5610
Dimensions displayed in inches unless otherwise stated
Ordering Reference
Ordering Reference
Thread SizeMinimum Thread LengthProtrusion Length 'F'Across Flats DimensionAcross Corners DimensionsMax Installation Torque (Nm)
781DM2781EM2M20 x 1.515.012.730.033.07
781DM3781EM3M25 x 1.515.012.736.039.610
781DT1781ET1½' NPT19.912.730.033.07
781DT2781ET2¾' NPT20.212.736.039.610
Dimensions displayed in millimeters unless otherwise stated

Technical Illustration

Additional Information

ATEX Insights

Comprehensive information on the use and application of the Directive ATEX 2014/34/EU, which became mandatory on 20th April 2016 can be obtained from the web resources. The third edition of the ATEX 2014/34/EU guidelines were issued in December 2017 and form an important reference point for member states to follow; they can be found here :

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Metallic Cable Glands

CMP brass cable glands are produced using material grade CuZn39Pb3 (CW614N) to EN12168 and EN12164. Stainless steel cable glands are produced using material grade 316L to BS EN 10088 : Part 3 -, and aluminium alloy 6082 and 6262 to EN 573-3 - for aluminium cable glands.

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What types of cables are affected by Coldflow?

‘Coldflow’ can affect any type of cable, whether onshore or offshore, armoured or unarmoured, and can arise on the outer sheath or the inner bedding of a cable, as it is the type of materials used to produce the cable, and not any specific category or particular group of cables, that defines if a cable is susceptible to ‘coldflow’ or not.

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Visit our Knowledge Base for technical expertise and advice, gathered over CMP's 60+ years' experience in the art of terminating cable glands.

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