Type POLIM -D..PI-2 Type POLIM -D..PI-3

Transcription

1 Operating instructions Surge arrester Type POLIM -D..PI-2 Type POLIM -D..PI-3 Publication No. 1HC AH With ABB metal-oxide resistors Without gaps For medium voltage metal enclosed switchgear with plug-in type bushings cone size 2 and 3 referring to EN Mounting and installation, maintenance, transportation, storage and disposal Issued by: ABB Switzerland Ltd. High Voltage Products Surge Arresters Jurastrasse 45 CH-5430 Wettingen 1 Contact information: Phone: +41 (0) Telefax: +41 (0) sales.sa@ch.abb.com Internet: We reserve the right to make changes. We reserve all rights to this document and the object presented within. Reproduction, passing on to third parties or utilisation of the contents is not permitted without our express consent. ABB Schweiz AG

2 Lamella contact Silicone cone Installation screw M8x45 Adapter flange Installation screw M8x20 Area of pressure-relief in case of overload and indication of arrester position Aluminium tube Red polymer hull Grounding bolt Washer M12 or M16 2 EN Doc. 1HC AH

3 Table of contents 1. ABOUT THIS DOCUMENT Validity Target group Copyright 4 2. SAFETY Symbols and advices Basic safety precautions Product safety Personnel-related measures Organisational measures 6 3. DESCRIPTION Intended use Structure and function Technical data Technical data on the surge arrester Application guidelines Behaviour in fire 9 4. TRANSPORTATION, UNPACKING AND STORAGE COMMISSIONING Safety Electrical check before commissioning Installation location and protective distance Mounting Preparing for installation Cleaning of silicone cone and plug-socket Greasing of silicone cone Mounting of adapter Mounting of surge arrester without surge counter Mounting of surge arrester with surge counter Removal of surge arrester without surge counter Removal of surge arrester with surge counter MAINTENANCE, UPKEEP Replacement after overloading DISPOSAL 27 Doc. 1HC AH EN 3

4 1. ABOUT THIS DOCUMENT These operating instructions are part of the POLIM -D..PI-2, POLIM -D..PI-3 surge arrester and describe safe and proper use for all phases of operation. We reserve the right to make changes in the interest of further development Validity These operating instructions are valid only for the POLIM -D..PI-2, POLIM -D..PI- 3 surge arrester Target group The target group of these operating instructions is professionals in the field of highvoltage technology. The POLIM -D..PI-2, POLIM -D..PI-3 may only be commissioned and maintained by persons instructed in proper use and handling Copyright The copyright of these operating instructions belongs to ABB Switzerland Ltd. These operating instructions are to be handled confidentially and are intended solely for mounting, operating and monitoring personnel. They contain regulations and illustrations of a technical nature which may neither be utilized for competitive purposes nor passed on to others. Handing over to third parties is impermissible and liable for compensation. All rights, including those regarding the translation, are reserved. 4 EN Doc. 1HC AH

5 2. SAFETY 2.1. Symbols and advices This is a safety sign. It warns you of the danger of injury and material damage. Follow all measures marked with the safety sign to avoid injuries, death and damage to materials. This safety sign warns you of the danger of death or serious injury from electric shocks. Follow all measures marked with the safety sign to avoid injuries and death. This mark indicates that an action is to be performed. Warnings in these operating instructions indicate special dangers and list measures for prevention of the danger. There are three levels of warning: Warning word DANGER WARNING CAUTION Meaning Immediate, impending endangerment of your life and health Possible impending endangerment of your life and health Possible impending danger of light injuries or damage to materials Warnings are structured as follows: WARNING WORD The type and source of danger appear here Possible consequences, which could occur if the measures are not followed, appear here. Impermissible actions appear here. Measures for avoiding the danger appear here. M8 13Nm The bolt of the given size shall be tightened with a torque wrench to the specified value Doc. 1HC AH EN 5

6 2.2. Basic safety precautions Product safety The POLIM -D..PI-2, POLIM -D..PI-3 has been constructed using state-of-the-art technology and officially recognised safety-related rules. Danger to life and health of the user or third parties could arise or damage of the POLIM -D..PI-2, POLIM - D..PI-3 and other property could occur while the POLIM -D..PI-2, POLIM -D..PI-3 is in use, however. The POLIM -D..PI-2, POLIM -D..PI-3 is only to be used when it is in technically sound condition, for the intended purpose, and with safety and the possible dangers in mind while observing the operating instructions. Keep the operating instructions intact and fully readable, and store them in such a way that they are accessible to operating personnel at all times. Decommission and replace overloaded or damaged POLIM -D..PI-2, POLIM - D..PI-3 units Personnel-related measures Train personnel in professional and safe working with high-voltage technology. Train and instruct personnel in working on the POLIM -D..PI-2, POLIM -D..PI- 3 using the operating instructions. Personnel being trained, instructed or provided with general education may only work with the POLIM -D..PI-2, POLIM -D..PI-3 under constant supervision by an experienced high-voltage technology professional Organisational measures Observe all safety- and danger-related information regarding the POLIM - D..PI-2, POLIM -D..PI-3. The safety rules of the owner of the high- and medium-voltage system and all regulations of the respective national safety authorities are to be observed. Only trained and instructed professionals may be authorised. Clearly assign areas of responsibility for working with the POLIM -D..PI-2, POLIM -D..PI-3. Make them known and adhere to them. Only personnel who have read and understood the operating instructions, especially the "Basic safety precautions" section may be allowed to carry out activities with the POLIM -D..PI-2, POLIM -D..PI-3. Check to ensure that work is being performed in a safety-conscious way with awareness of possible dangers and while observing the operating instructions. 6 EN Doc. 1HC AH

7 3. DESCRIPTION 3.1. Intended use The POLIM -D..PI-2, POLIM -D..PI-3 is a surge arrester intended for use in medium voltage metal-enclosed switchgear applications with plug-in type bushings referring to EN Surge arresters protect the insulation of medium voltage devices against overvoltages which are caused by lightning or switching operations. The manufacturer is not liable for resulting damages from further, unintended use. The operator accepts all responsibility for using the POLIM -D..PI-2, POLIM - D..PI-3 outside of its intended application range as specified in this document Structure and function The POLIM -D..PI-2, POLIM -D..PI-3 surge arrester is constructed from serially connected, non-linear metal-oxide (MO) resistors. These MO resistors have an extremely non-linear resistance property. At the maximum operating voltage of U c, only a small capacitive current will flow in the ma range. With an increase in voltage, the MO resistors enter a highly-conductive state practically without delay. Thus any further increase in voltage is limited to the specified residual voltage values. After the decline of the overvoltage the arrester immediately turns back to the non- or slightly-conductive state. The MO arrester converts the energy of the surge into heat, which it transfers to the surrounding ambience. The stack of MO resistors and connection equipment is held together with loops made of fiberglass-reinforced plastic. The MO resistors are enclosed by silicone to insulate against the metal housing. The aluminium housning assures optimal safety for operation personnel. Plug-in surge arresters are available in cone size 2 or size 3 according to EN Personal security: The surge arresters are mounted in a closed buildning to which only qualified personnel, working within the high power field, have access. Doc. 1HC AH EN 7

8 3.3. Technical data The technical data, dimensions and weights are specified in the following documents: surge arrester POLIM -D..PI-2, POLIM -D..PI-3 in the 3273 pamphlet POLIM -D..PI-2, POLIM -D..PI-3 dimensional drawings Technical data on the surge arrester The rating plate contains the following data: Data POLIM -D.. PI-2 POLIM -D.. PI-3 Uc =.. kv Ur =.. kv In =.. ka No. HA... Dat. Meaning Complete type designation with specification of the maximum permissible continuous operating voltage U c and cone size Maximum permissible continuous operating voltage U c Rated voltage Nominal discharge current Serial number Date of manufacture 8 EN Doc. 1HC AH

9 Application guidelines The following guidelines apply for the use of POLIM -D..PI-2, POLIM -D..PI-3 surge arresters: "Application guidelines" for medium-voltage systems, pamphlet 3021EN Behaviour in fire The silicone housing of the surge arrester is self-extinguishing, and the oxygen index (LOI), measured in accordance with ASTM D 2863 and EN ISO 4589 is greater than 35. Doc. 1HC AH EN 9

10 4. TRANSPORTATION, UNPACKING AND STORAGE Transportation CAUTION Surge arresters not secured during transportation Damage to surge arresters that have fallen during transport. Secure surge arresters against sliding or falling before transportation. Observe safety precautions printed on the packaging for proper handling during transportation and storage. Unpacking The surge arresters provided are packaged in cardboard boxes, which shall protect the arresters against damage during the transport. Observe that each surge arrester package consists of two boxes (one with the surge arrester, the other with needed accessories), which are strapped together. In case the surge arrester is delivered with surge counter another box containing the surge counter and accessories are provided. After receiving the shipment, compare the order and delivery documents immediately to check for completeness and accuracy of the shipment. In case of incompleteness or deviations, inform the supplier and shipper immediately. Each arrester shall be delivered with: 1 x adapter flange 3 x installation screws, M8x20 3 x installation screws, M8x45 1 x installation grease 1 x 0,5D-M12 nut (POLIM-D..PI-2) 2x 0,5D-M16 0.5mm nut (POLIM-D..PI-3) 2 x washer for M16 (POLIM-D..PI-3) In case the arrester is equipped with a surge counter 1 x surge counter 1 x coupling 1 x thread bolt 1 x M12 nut 1 x 0,5D-M12 nut 2 x washer for M12 10 EN Doc. 1HC AH

11 WARNING Damaged surge arresters Material damage and personal injury due to the installation and commissioning of damaged surge arresters. Do not use damaged surge arresters. Examine shipment immediately to check for damage. The silicone cone should be without any kind of damages such as rifts, grinded areas or impurities (particles) The visible black conductive layer coat must be free of damages The aluminium tube shall not be damaged Notify the insurance company, the shipper and the supplier of the damage immediately and create a damage log. Storage The original packaging materials can be used for storage. Store surge arresters in a well-ventilated, clean room. Doc. 1HC AH EN 11

12 5. COMMISSIONING 5.1. Safety System uses high voltage DANGER Death, serious bodily harm and damage to the switching gear may result from an electric shock. Allow only authorised professionals to perform work on the surge arrester. Observe the safety rules of EN before working on the system: Disconnect the system from the power supply. Secure the system against being switched on again. Ensure that the system is de-energised. Earth the system and short-circuit it. Cover or cordon off neighbouring energised parts Electrical check before commissioning Each surge arrester is tested by the manufacturer. The routine test report is included with the packaging. Additional electrical testing before commissioning is not necessary Installation location and protective distance Danger of fire and injury via arc with overloading of the surge arrester DANGER Ignition of flammable materials by an arc and flying burning parts. Do not store flammable materials near the surge arrester. When working near the surge arrester, do not wear easily flammable clothing. Plug-in surge arrester shall only be mounted in plugs with the same size. The plug sizes have to fulfil the rolerances according to DIN EN and DIN The thickness of the mounting plate has to conform the standards DIN EN and DIN and shall not exceed 14.5mm. Surge arresters only protect high- and medium-voltage apparatuses when they are located within the protective distance.the protective distance is only a few meters. Always mount surge arresters as close as possible to the apparatus to be protected within the protective distance. The length of the connecting cables are decisive here. In cases of doubt, calculate the protective distance according to the formulas in the "Application guidelines". 12 EN Doc. 1HC AH

13 5.4. Mounting CAUTION Incorrect system voltage Damage to the switching gear and the surge arrester. Do not use surge arresters intended for a.c. systems in d.c. systems. Observe the "Application guidelines" from ABB Switzerland Ltd. Before mounting, ensure that the characteristic data on the rating plate of the surge arrester matches the requirements of the power system. Ensure that system voltage applied at the terminals of the arrester does not exceed the maximum permissible continuous operating voltage of the surge arrester Preparing for installation Check that the silicone cone has no damage Cleaning of silicone cone and plug-socket Clean the silicone cone and plug-socket with Isopropyl or cable cleaning agent (from ABB). Let the cone and socket to dry in the air for approximately 15 minutes. In order to achieve faultless operation, it s important that both the plug-socket and the arrester silicone cone are clean. The cone shall be cleaned with Isopropyl or cable cleaning agent (from ABB) before installation. A clean, soft and fluff-free cloth shall be moistened with Isopropyl or cable cleaning agent. Towel the cone with moderate pressure. Surplus cleaning agent can be wiped off with a dry rag. The cone will slightly swell due to this cleaning treatment but will recover within a couple of minutes. It s therefore important to let the cone dry in the air for approximately 15 minutes before greasing. Clean the plug-socket before operation with Isopropyl. In case of short-time disconnection of the plug connection the grease film can be left under condition that the grease is not polluted Greasing of silicone cone Only use the enclosed installation grease. Apply the grease immediately before installation. Check that the installation grease is evently spread on the silicone cone. Doc. 1HC AH EN 13

14 Clean and grease the silicone cone before installation In order to achieve an optimal insulation between the silicone cone of the surge arrester and the plug-socket the cone shall be lubricated with enclosed installation grease before mounting. The grease should be applied immediately before installation in order to avoid pullution. Only use the enclosed installation grease! Cone size 2 Required amount of installation grease for each surge arrester is approximately 5g or about half of the whole packet. Cone size 3 Required amount of installation grease for each surge arrester is approximately 10g or the whole packet. 14 EN Doc. 1HC AH

15 Mounting of adapter Capacitive divider connection, if provided by the switchgear manufacturer, has to be installed before the mounting of the adapter flange. M8 Tightening torque provided by switchgear manufacturer Adjust the adapter flange to desired position and fix it with the provided screws M8 45 to the designated threaded holes of the plug-socket. If the capacitive divider connection is to be used, please adjust the adapter flange in such way allowing the cable to be connected. The screws should be tighten with a tightening torque specified from the switchgear manufacturer. The screws have strength class 12.9 according to DIN-ISO 898. Doc. 1HC AH EN 15

16 Mounting of surge arrester without surge counter CAUTION Incorrect mounted surge arrester Damage to the surge arrester. Do not turn the arrester after mounting Place the arrester in correct posistion before inserting the arrester in the plugsocket. 1 M8 13Nm 2 Please observe that this chapter deal with plug-in arresters without surge counters. In case the arrester shall be equipped with a surge counter please see chapter The surge arrester is delivered pre-stressed from the factory, which allows manual mounting into the plug-socket with moderate force. The standard arrester mounting postion is vertically cone upright. Other mounting positions on request. Insert the surge arrester in vertical position without canting or bending the lamella contact. Fix the aluminium tube (1) with the pre-assembled M8 20 screws using a tightening torque of 13 Nm. Do not turn the arrester after mounting! Remove the nuts, washers and the red polymer hull (2) from the grounding bolt. The red polymer hull shall be stored for the removal of the Plug-in arrester. In case of loss new hulls can be ordered at ABB Switzerland Ltd, PTHA, Wettingen (Material No: 1HC ). The polymer hull is only an assembling tool. 16 EN Doc. 1HC AH

17 Surge arrester with insulated terminal E DANGER Death, serious bodily harm and damage to the switching gear may result from an electric shock. The leakage current is connected to terminal E, which is insulated from earthed enclosure. The terminal E is to be connected to earth with a cable Incorrect mounted surge arrester Damage to the surge arrester. caution Do not energise if this the requirement below is not fulfilled. The red polymer hull shall never remain assembled in service A surge arrester is correctly mounted if about 50% or more of the area seen trough the window is red 5a) POLIM-D..PI-2 M12 or M16 40Nm 6 3 I II E Minimum 8mm 5b) POLIM-D..PI-3 4 III E 6 Minimum 8mm 5 6 Minimum 8 mm E Check if the surge arrester is in correct position (3). There are in total six circular windows situated at the top of the aluminium tube. Only one of these windows has to be checked. A surge arrester is correctly mounted if about 50% or more of the area seen trough the window is red. Do not energise if this requirement is not fulfilled. Use a flexible ground connection lead of minimal dimension 16 mm 2 (4). By using a flexible lead no counter force is applied to the spring and repositioning of the cone is avoided. Any additional forces, except the arresters own force by weight, are not accepted. Doc. 1HC AH EN 17

18 POLIM-D..PI-2 (5a). Fix the earth connection with the two nuts (I) & (II) and two washers. Observe that the lower nut is a 0,5D-M12 (delivered). Observe that there must be a minimum distance of 8 mm between the aluminium tube and the first nut (6). The nuts have to be secured by a tighten torque of 40 Nm counter measured. POLIM-D..PI-3 (5b). Fix the earth connection with the two nuts (III) and two washers. Observe that the nuts and washer to be used are 0,5D-M16 and the smaller washers (delivered). Observe that there must be a minimum distance of 8 mm between the aluminium tube and the first nut (6). The nuts have to be secured by a tighten torque of 40 Nm counter measured 18 EN Doc. 1HC AH

19 Mounting of surge arrester with surge counter CAUTION Incorrect mounted surge arrester Damage to the surge arrester. Do not turn the arrester after mounting! Place the arrester in correct posistion before inserting the arrester in the plugsocket. M8 13Nm 1 2 Please observe that this chapter deal with plug-in arresters with surge counters. In case the arrester shall not be equipped with a surge counter please see chapter The surge arrester is delivered pre-stressed from the factory, which allows manual mounting into the plug-socket with moderate force. The standard arrester mounting postion is vertically cone upright. Other mounting positions on request. Insert the surge arrester in vertical position without canting or bending the lamella contact. Fix the aluminium tube (1) with the pre-assembled M8 20 screws using a tightening torque of 13 Nm. Do not turn the arrester after mounting! Remove the nuts, washers and the red polymer hull (2) from the grounding bolt. The red polymer hull shall be stored for the removal of the Plug-in arrester. In case of loss new hulls can be ordered at ABB Switzerland Ltd, PTHA, Wettingen (Material No: 1HC ). The polymer hull is only an assembling tool. Doc. 1HC AH EN 19

20 DANGER caution Surge arrester with insulated terminal E for surge arrester monitoring Death, serious bodily harm and damage to the switching gear may result from an electric shock. The leakage current is connected to terminal E, which is insulated from earthed enclosure. The terminal E is to be connected to earth via monitoring instrument with a cable Incorrect mounted surge arrester Damage to the surge arrester. Do not energise if this the requirement below is not fulfilled A surge arrester is correctly mounted if about 50% or more of the area seen trough the window is red 3 M12 or M16 40Nm 4 8 Minimum 5mm 6 E 5 7 Check if the surge arrester is in correct position (3). There are in total six circular windows situated at the top of the aluminium tube. Only one of these windows has to be checked. A surge arrester is correctly mounted if about 50% or more of the area seen trough the window is red. Do not energise if this requirement is not fulfilled. Place the coupling (5) and a washer over the insulated terminal E and screw the 0,5D-M12 or 0,5D-M16 nut as shown by (6). Observe that there must be a minimum distance of 5 mm between the aluminium tube and the coupling (4). 9 4 Minimum 5mm E EN Doc. 1HC AH

21 Screw the thread bolt into the coupling and place sensor over the bolt (7). Observe that the sensor side marked with earth symbole should face the earth connection. Use a flexible ground connection lead of minimal dimension 16 mm 2 (9). By using a flexible lead no counter force is applied to the spring and repositioning of the cone is avoided. Any additional forces, except the arresters and sensors own force by weight, are not accepted. Fix the earth connection and sensor with the two M12 nuts and two washers (8). Observe that the outer nut is a 0,5D-M12 (delivered). The nuts have to be secured by a tighten torque of 40 Nm counter measured. Doc. 1HC AH EN 21

22 Removal of surge arrester without surge counter System uses high voltage DANGER Death, serious bodily harm and damage to the switching gear may result from an electric shock. Allow only authorised professionals to perform work on the surge arrester. Observe the safety rules of EN before working on the system: Disconnect the system from the power supply. Secure the system against being switched on again. Ensure that the system is de-energised. Earth the system and short-circuit it. Cover or cordon off neighbouring energised parts. The surge arrester shall be completely removed from the plug-socket in any case of measuring cable faults or voltage measuring of the equipment. 3a) POLIM-D..PI-2 I II 4 3b) POLIM-D..PI-3 1 III 2 IV E Remove the flexible ground leads and the nuts from the insulated terminal E bolt (1) & (2). 22 EN Doc. 1HC AH

23 POLIM-D..PI-2 (3a). Push the red polymer hull over the grounding bolt up towards the bottom of the aluminium tube. Fix the hull by means of two M12- nuts and two washers. Observe that two M12 nuts, delivered with the surge arrester, are needed. The lock nut need to be counter held by a spanner. Tighten until total resistance is noticed. POLIM-D..PI-3 (3b). Push the red polymer hull over the grounding bolt up towards the bottom of the aluminium tube. Fix the hull by means of one M16 bult and one 0,5D-M16 bult and two bigger washers. Observe that two bigger washes, delivered with the surge arrester, are needed. The lock nut need to be counter held by a spanner. Tighten until total resistance is noticed. The red colour in the window area is no longer visable (4). Remove the three M8x20 screws fixing the aluminium tube to the adapter flange. Observe that the arrester has to be manually secured against falling down. Remove the surge arrester from the plug-socket by gently pulling it out in vertical direction. Be careful not to damage the silicone cone. Store disassembled in a clean and dry environment. The silicone cone has to be protected against any type of damages. Doc. 1HC AH EN 23

24 Removal of surge arrester with surge counter System uses high voltage DANGER Death, serious bodily harm and damage to the switching gear may result from an electric shock. Allow only authorised professionals to perform work on the surge arrester. Observe the safety rules of EN before working on the system: Disconnect the system from the power supply. Secure the system against being switched on again. Ensure that the system is de-energised. Earth the system and short-circuit it. Cover or cordon off neighbouring energised parts. The surge arrester shall be completely removed from the plug-socket in any case of measuring cable faults or voltage measureing of the equipment. 6a) POLIM-D..PI-2 7 I II 6b) POLIM-D..PI III IV 4 1 E 24 EN Doc. 1HC AH

25 Remove the flexible ground leads and the nuts from the thread bolt (1) & (2). Gently remove the sensor (3). Remove the nut, washer (4) and the coupling (5). POLIM-D..PI-2 (6a). Push the red polymer hull over the grounding bolt up towards the bottom of the aluminium tube. Fix the hull by means of two M12- nuts and two washers. Observe that two M12 nuts,delivered with the surge arrester, are needed. The lock nut need to be counter held by a spanner. Tighten until total resistance is noticed. POLIM-D..PI-3 (6b). Push the red polymer hull over the grounding bolt up towards the bottom of the aluminium tube. Fix the hull by means of one M16 bult and one 0,5D-M16 bult and two bigger washers. Observe that two bigger washes, delivered with the surge arrester, are needed. The lock nut need to be counter held by a spanner. Tighten until total resistance is noticed. The red colour in the window area is no longer visable (7). Remove the three M8x20 screws fixing the aluminium tube to the adapter flange. Observe that the arrester has to be manually secured against falling down. Remove the surge arrester from the plug-socket by gently pulling it out in vertical direction. Be careful not to damage the silicone cone. Store disassembled in a clean and dry environment. The silicone cone has to be protected against any type of damages. Doc. 1HC AH EN 25

26 6. MAINTENANCE, UPKEEP System uses high voltage DANGER Death, serious bodily harm and damage to the switching gear may result from an electric shock. Allow only authorised professionals to perform work on the surge arrester. Observe the safety rules of EN before working on the system: Disconnect the system from the power supply. Secure the system against being switched on again. Ensure that the system is de-energised. Earth the system and short-circuit it. Cover or cordon off neighbouring energised parts. The surge arresters do not contain wearing parts and are therefore maintenancefree. Replacement parts are not needed. However, the silicone cone needs to be cleaned before mounting (see Preparing before installation, chapter 5.4.1) Replacement after overloading Overloading during operation can lead to damaging (e.g. traces of fire, fractures) of the surge arrester from arcs. Damage to the surge arrester Damaged surge arresters no longer protect the switchgear. CAUTION Check the surge arresters visually on a regular basis to ensure that they are in sound condition. Replace damaged surge arresters. Keep a small percentage of installed surge arresters in reserve. 26 EN Doc. 1HC AH

27 7. DISPOSAL POLIM -D..PI-2, POLIM -D..PI-3 surge arresters are environmentally-friendly products which must be disposed of based on the respective applicable regional regulations in an environmentally-friendly manner. The materials should be given up for recycling. Constituent components are: silicone rubber (not halogenated) for the external insulation mounting sections and other parts made of aluminium metal-oxide varistors fibreglass-reinforced plastic lugs steel mounting hardware Silicone rubber (not halogenated) The silicone rubber can break down into SiO 2 and CO 2, thus uncovering the encased metal-oxide varistors. Metal-oxide varistors The metal-oxide varistors are sintered ceramics consisting up to 90% of ZnO. The following additions are also contained within: percent by weight over 1%: Bi 2 O 3 and Sb 2 O 3, which are considered to be dangerous substances according to EU ordinances percent by weight between 0.1 and 1%: NiO and Cr 2 O 3, which are considered poisonous and dangerous materials pursuant to EU guideline 91/689/EEC Metal-oxide varistors are coated with a thin glass coating containing lead-oxide (< 0.1% of the weight). The substances are present as an oxide in metal-oxide varistors. A wash-out test in accordance with an EPA specification (Federal Register/vol. 45, No 98 /Rules and regulations) has shown that the sintered metal-oxide varistors can be disposed of as industrial waste without infringing on EEC guidelines. No danger to personal health or the environment is present during normal operation. Doc. 1HC AH EN 27