Discuss two installations, one earth rod in the Periodic Inspection Reporting & Certification area at ElectriciansForums.net
A means of earthing is the arrangement through which a connection is made to the general mass of Earth. For an installation forming part of a TT system, the means of earthing is an installation earth electrode. As for any earth electrode, that for a TT system has to meet certain requirements. For example Regulation 542.2.4 requires the type and embedded depth of an earth electrode to be such that soil drying or freezing will not increase its resistance above the required value. Furthermore, the design used, and the construction of, an earth electrode is required by Regulation 542.2.1 to be such as to withstand damage and to take account of possible increase in resistance due to corrosion. Details of these requirements for earth electrodes are given in Section E5 of the Essential Guide. Reference should also be made to item 4 of this topic, which addresses the relevance of the earth electrode resistance with respect to ADS requirements for TT systems. In a TT system, every exposed-conductive-part protected by a single protective device has to be connected to a common earth electrode via the MET. However, if two or more protective devices are in series, the exposed-conductive-parts may be connected to separate earth electrodes corresponding to each protective device (Regulation 411.5.1). Refer to Fig 2. | |
Exposed-conductive-parts connected to separate installation earth electrodes Fig 2 A requirement which must not be overlooked, however, in situations where there is more than one means of earthing (such as that shown in Fig 2), is that of Regulation 411.3.1.2 that simultaneously accessible exposed-conductive-parts have to be connected to the same earthing arrangement to prevent such parts attaining substantially different voltages with respect to one another. This is further explained in Topic E45-65. |
If these 2 supplies are separately DNO metered, then each building will require a separate TT system, end of!!
If these 2 supplies are separately DNO metered, then each building will require a separate TT system, end of!!
Reply to two installations, one earth rod in the Periodic Inspection Reporting & Certification area at ElectriciansForums.net
We get it, advertisements are annoying!
Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.