The minimum ground cover should not be less than mm and ideally the surrounding soil should be damp. The majority of the formulae presented in this section relate to low frequency currents and high frequency examples are not included. The major hazard involved with the transfer of flammable liquids is the build up of static due to charge separation with potential for discharge resulting in fire and subsequent loss of containment. Basic concepts and methodology, British Standards Institution. It covers earthing system design parameters for structures, electrical equipment and systems.
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Section 10, Paragraph It is of particular relevance to: Corrosion of concrete encased steelwork, subject earthimg a. When two or more strips in straight lengths, each of length L in meters m and a separation distance s metres are laid parallel to each other and connected together at one end only the combined resistance may be calculated from the following equation:.
BS +A Code of practice for protective earthing of electrical installations
However, onsite resistivity testing should always be carried out prior to carrying out an earth system design and installation. Paragraph 33 recommends the earthing of flexible hoses. This requires careful assembly during installation to ensure that the bottom of the plate is resting in the medium used and not on the chalk or high resistivity substrata. Plates, if used, should be installed as small units of not greater than 1.
It also notes that there may be applications, such as cathodic protection, where such low resistance to earth is undesirable.
General considerations, British Standards Institution.
Part 1, section 7. Paragraph earting gives guidance on earthing of road tankers. This connection should have a resistance not greater than that required to operate safety mechanisms to isolate the electricity supply from a fault situation.
Paragraph 90 provides guidance of the earthing of flexible hoses. Intrinsically safe electrical apparatus and systems, British Standards Institution. It covers earthing system design parameters for structures, electrical equipment and systems. This Technical Measures Document refers eartthing codes and standards applicable to earthing of plant.
It should be noted that environmental conditions such as temperature have an impact on earth resistivity with a corresponding decrease in resistivity as temperature rises. Care should be taken to avoid a site where water flows over it e. Take the smart route to manage medical device compliance. A key function of equipment earthing is to provide a controlled method to prevent the build up of static electricity, thus reducing the risk of electrical discharge in potentially hazardous environments.
A waterlogged location is not essential unless the soil is sand or gravel. Overview Product Details What is this standard about? Larger pipes require lower velocities; A general rule for all homogeneous liquids except carbon disulphide and ether and all pipelines: The major hazard involved with earthkng transfer of flammable liquids is the build up of static due to charge separation with potential for discharge resulting in fire and subsequent loss of containment.
Has been superseded by BS EN Low resistivity eartthing, e. Above ground and at anchor bolts it may generally done by attaching a bond conductor to bypass each structural joint.
The relevant Level 2 Criteria are 5. The mesh should be bonded to the metal flanges or coupling of the hose; If a metal hose with a liner is employed, ewrthing metal mantle and flanges or couplings must be bonded to each other; The electrical resistance between the two couplings must not be higher than 10 6 ohms.
Stringent precautions are required to prevent accumulations of static electricity and to give protection against lightning. Manish Darji Feb 26, Customers who bought this product also bought BS EN For conventional sizes, the resistance is approximately inversely proportional to the linear dimensions, not to the surface areai.
Paragraphs to give 7403 on earthing requirements for the tank structure. This should encompass the storage vessel and all supporting ancillary equipment. They may be used to give an indication of the difficulties that one might face in preparing an adequate design at the chosen location.