T&D Get Down To Earth With Scottish Windfarms

By Chris Dodds on 14th December, 2012

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This week, T&D have supplied 10 pallets of Marconite Earthing Compound to 3R Energy Ltd.

T&D have an impressive track record supplying AN Wallis Earthing & Lightning Protection, 3M Cold Shrink Cable Joints & Terminations, CSD Duct Seals, Polypipe Cable Ducting, Nexans Euromold Cable Connectors and Centriforce Underground Cable Protection Covers to the Scottish renewable energy industry.

Marconite Compound

Marconite is a granulated electrically conductive aggregate which replaces sand in mixes with cement, thereby providing electrically conductive concrete.

Electrodes (including copper earth rods) can be encased in Marconite mixture to greatly increase their surface area, lowering the resistance to earth.

Marconite benefits include low resistivity, conduction of current is electronic (not ionic), permanent and stable, increased surface area contact. Marconite has been approved and used by the MOD, electrical utilities, rail systems and water companies.

1. What Makes Marconite Unique?

• Other earthing materials marketed as conductive aggregatres include low grade carbonaceous by-products from other industries which include coal, metallurgical coke, power station clinker, carbon black, Bentonite and others. All of these products can be called conductive with resistivity of 5 ohms metres.
• The resistivity of Marconite is in the order of .001 ohm metres. When mixed with cement the resulting conductive concrete is still only 0.19 ohm metres.
• This is significantly lower than Bentonite for example, which has a typical resistivity of 3 ohms metre upwards.
• Typically the above products can include anything between 15-20% impurities which are corrosive and will corrode earth connections resulting in the loss of the system which can prove to be very, very expensive.
• Marconite has no such impurities and at PH7 is non corrosive.
• Marconite is manufactured specifically for earthing, it is not a by-product.

2. Application

Marconite and Earthing of Towers

Towers used for power distribution, lighting and communication aerials are usually supported on foundations with each leg on an individual concrete base or all legs on a reinforced concrete slab. earthing is traditionally completed with earth electrodes using conventional earth rods or tapes.

• A. Marconite conductive concrete has a resistivity of 0.1 ohm metre.
• B. Marconite can be placed as a blinding layer when excavating the foundations and connected by copper tape to the tower.
• C. Bore holes are not required thereby reducing drilling and copper costs.
• D. By incorporating a blinding layer with the foundation block the area available is considerable when compared to a single electrode, enabling the resistance required to be achieved.

Marconite and Earthing of Substations

Substations are earthed to contain any fault current within their boundaries.

At the perimeter Bore Hole with Marconite is constructed all around ie if 20 metre bore hole is done - then next one will be done at 20 metrer distance. This is done all around the perimeter.

A 100mm dia bore hole with a 16mm copper rod encapsulated with Marconite has a large area of dissipation that will ground any fault current faster and more safely when compared to a 16mm dia rod.

3. Key Advantages of Marconite

Custom designed and proven in a wide range of applications including power generation,distribution, oil, gas and rail.

• Suitable for all soil conditions - Marconite can give the lowest potential to earth for a wide range of soils, including granite, sand, glacial rock and made up ground.
• Cost effective - Price is not cost. Using Marconite will achieve savings in drilling, copper, maintenance and installation costs
• Mechanical Strength - Where required the “Marconite” Pre- mix provides a high mechanical strength.
• Inert at PH7 - Marconite is non corrosive to steel, copper bonded rods and does not attack cement structures, important in hostile conditions.

Maintains integrity of earthing systems - Marconite encapsulation protects earthing systems in corrosive soil conditions.

• Easy to use - Marconite is normally mixed 2 : 1 by weight with cement and will absorb 15% of its own weight of water.
• Fast drying - Marconite is selected to give fast drying. No sand or other aggregates are necessary.
• Permanent - Marconite has an indefinite shelf life. When mixed with cement it retains its performance after drying, has 20 years proven experience.
• Greater surface area contact with earth - Under certain difficult ground conditions with high resistivity such as glacial rock or granite, if compressive strength is not an issue, the Marconite and cement mix with additional water can be made into a slurry. This will leech into the cracks and fissures greatly increasing ground contact- like an inverted tree with a large root system-helping to achieve a low resistance value.

Marconite® Conductive Concrete is a registered product of the James Durrans Group and is solely produced by their subsidiary company Carbon International Limited.

T&D provide fast delivery and competitive prices for genuine Marconite brand Earthing Products.

T&D have an impressive track record supplying AN Wallis Earthing & Lightning Protection, 3M Cold Shrink Cable Joints & Terminations, CSD Duct Seals, Polypipe Cable Ducting, Nexans Euromold Cable Connectors and Centriforce Underground Cable Protection Covers to the Scottish renewable energy industry.

• Further Reading

Class 1 PVCu Underground Cable Duct From Polypipe For 33kV Power Cable Protection

Polypipe Ridgicoil Cable Duct Protects Underground Power & CCTV Cable In Oil & Gas Industry

Polypipe Ridgicoil Underground Cable Ducting For PV Solar Farm Cables

 

Thorne & Derrick Specialist Electrical Distributor

Established since 1985, T&D distribute the most extensive range of LV, MV & HV Cable Jointing, Terminating, Pulling & Installation Equipment - contact us today for a competitive quotation.

Key Products : MV Joints & Terminations, Cable Cleats, Duct Seals, Cable Transits, Underground Cable Protection, Jointing Tools, Feeder Pillars, Cable Duct, Earthing & Lightning Protection, Electrical Safety, Cable Glands, Arc Flash Protection & Fusegear.

Distributors for : 3M, Pfisterer, Nexans Euromold, Elastimold, Catu, Roxtec, Emtelle, Centriforce, Lucy Zodion, Alroc, Hivotec, Cembre, Prysmian, Ellis Patents, ABB & Furse.

 

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Category:  Earthing & Lightning Protection

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