Corporate Standard 0001/MUCEN 1 History Version Valid from Author Modification 1st July 2008 K. Wianski / A.Triebe First edition 2 Scope of Application This corporate standard shall apply to combinations of electrical equipment such as e.g. low-voltage switchgear combinations according to DIN VDE 0660 Part 500 (EN 60439-1) and is based on the SIEMENS guidelines ELAN-RA. 3 Purpose This corporate standard specifies the uniform realization of safety measures with protective conductors. 4 General According to DIN VDE 0100 Part 410, bodies 1) of electrical equipment have to be connected to a protective conductor (PE) for being protected against indirect contact. As protective conductor (PE) according to DIN VDE 0100 Part 450, the following may be used: - green/yellow conductor in multi-wire cables and lines - insulated or bare conductors - metallic coatings such as sheathings, shields and concentric conductors of certain cables - metal coatings, e.g. of busbar systems - external conductive parts - constructional parts If the protective conductor (PE) is composed of constructional parts of switchgear combinations or of external conductive parts, a continuous electrical connection has to be ensured either by means of the structure or by using appropriate connections. 1) According to DIN VDE 0100 Part 200, a body is a tangible conductive part of an electrical equipment which normally is not exposed to voltage, but might be exposed to voltage in case of an error. Page: 1 of 9 WN-No. WN 0001 MUCEN
Corporate Standard 0001/MUCEN Appropriate connections can be established by means of: - screw connections - welded or riveted joints 5 Implementation DIN VDE 0660 Part 500 only contains statements applicable to protective conductors (PE) which are inserted from outside. Section 7.4.3.16 stipulates that individually detachable connecting points have to be available for all protective conductors (PE) coming from outside and going to the outside. This does not include connections of several protective conductors (PE) of an electric circuit (e.g. parallel cables). These may be clamped together under an appropriate connecting point. There are no stipulations concerning this for internal protective conductor connections. Thus, the following shall apply: - As far as possible, internal protective conductor connections should be abandoned and the parts of the equipment should be involved in the safety measures via attachment. - For equipment which cannot be involved in the safety measures via attachment, individual protective conductor connections between the equipment and the mounting plate, protective conductor terminal blocks or protective conductor rails (e.g. by means of conductor connecting terminals) have to be provided. Protective conductor loops which might involve interruption are inadmissible! If in exceptional cases protective conductor loops are formed (due to many connections), these loops must be carried out in such a way that the protective conductor connection cannot be interrupted in case of the removal of an equipment e.g. by crimping of two finely stranded conductors of the same cross-section in a cable lug. Page: 2 of 9 WN-No. WN 0001 MUCEN
Corporate Standard 0001/MUCEN 6 Dimensioning of the Protective Conductors (PE) (DIN VDE 0660 Part 12 and 500) External conductor (mm²) Protective conductor (PE) 4 10 same cross-section as external conductor 16 35 minimum 16 mm² 50 400 50% of the cross-section of the external conductor 500 800 minimum 200 mm², calculated separately 7 Use of Connecting Material Protective conductor (PE) (mm²) Connecting screw 10 M 6 16 25 M 8 35 50 M 10 70 95 M 12 Preferably, parts of the same material or of the same surface are to be connected. If the materials are different, the bigger part (body) has to consist of the base material and the smaller part (connecting material) has to consist of the nobler material or metal coating in order to avoid corrosion of the contact point (table 1). 8 Screw Connections - fig. 1 Grounding bolt Explanations for Fig. 1, 2, 3, 4, 5 1 Screw 1a Ground bolt 2 Contact disc 3 Hexagonal nut 4 Washer 5 Spring Washer 6 Ring connector (PE) 7 Serrated washer 8 Copper base plate Page: 3 of 9 WN-No. WN 0001 MUCEN
Corporate Standard 0001/MUCEN fig. 2 Grounding screw for through-hole for tightening torque refer to table 3 / columns 2 & 3 (="Reihe 6") fig. 3 Grounding screw for threaded hole 8 for tightening torque and min. length of engagement refer to tables 3 and 4 Page: 4 of 9 WN-No. WN 0001 MUCEN
Corporate Standard 0001/MUCEN fig. 4 Attachment of grounding strap fig. 5 PE rail for tightening torque refer to table 3 / columns 2 & 3 (="Reihe 6") Page: 5 of 9 WN-No. WN 0001 MUCEN
Corporate Standard 0001/MUCEN - fig. 6 Conductor connecting terminal Explanations for fig. 6: 6A PE 1 4 mm 2 6B PE 6 16 mm 2 6C PE 25 50 mm 2 7 --- 8 feeder clamp 4 mm 2 tightening torque 1/2/1 Nm 9 feeder clamp 16 mm 2 tightening torque 5 Nm 10 feeder clamp 50 mm 2 tightening torque 15 Nm 11 copper base plate Page: 6 of 9 WN-No. WN 0001 MUCEN
Corporate Standard 0001/MUCEN 9 Tables Page: 7 of 9 WN-No. WN 0001 MUCEN
Corporate Standard 0001/MUCEN Table 2 Conductive screw connections of blank and color-coated conductive parts for indoor use Page: 8 of 9 WN-No. WN 0001 MUCEN
Corporate Standard 0001/MUCEN Table 3 Tightening torque for production and testing Table 4 Minimum thread reach into materials considering tightening torque of Table 3 Page: 9 of 9 WN-No. WN 0001 MUCEN