BS Outcomes 6

Transcription

1 BS Outcomes 6 Inspection and testing 6.1 Identify the general requirements for inspection and testing of installations 6.2 State the need for diagrams, charts or tables to be available e prior to the verification process. 6.3 Identify the items to be checked during the inspection process. 6.4 State the tests which may need to be carried out on initial verification* 6.5 Compare test results with relevant criteria 6.6 State the requirements for the issue of a Electrical Installation Certificate b Minor Works Certificate c Periodic Inspection Report. *Detailed testing procedures are not covered in this qualification as this is detailed within the City & Guilds Level 2 Certificate in fundamental inspection, testing and initial verification ( ). Legh Richardson 1

2 610 Initial Verification A skilled person or a person competent in such work Legh Richardson 2

3 611 Inspection Part 6: Inspection and Testing Inspection precedes testing with the supply turned off Inspection to verify: 1. Equipment and accessories complies with a standard/s 2. Correctly selected and erected 3. Not visibly damaged seventeen items to inspect including: 1. Connections and identification of conductors 2. Routing of cables 3. selection of cables 4. Polarity 5. Fire barriers 6. Protection against electric shock 7. Labeling, diagrams, instructions and charts Legh Richardson 3

4 612 Sequence of testing 1. Continuity of protective conductors (including main equipotential bonding) 2. Continuity of ring final circuit 3. Insulation resistance 4. Protection by SELV, PELV or separation 5. FELV systems 6. Barriers and enclosures to IP2X, IPXXB, IP4X, IPXXD 7. Insulation resistance of Floors and Walls 8. Polarity 9. Earth Electrode resistance 10. Protection by Automatic Disconnection 11. Earth Fault Loop Impedance 12. Additional Protection 13. Prospective Fault Current 14. Check Phase Sequencing 15. Functional Testing 16. Verification of Volt Drop Legh Richardson 4

5 612.2 Continuity of protective conductors Low reading Ohmmeter; Instrument capability 4 24V at 200mA short circuit current Method 1 Long Lead method Method 2 Link out and measure at accessories Legh Richardson 5

6 Ring Final circuit testing Spur from Origin Spur from FCU Double Link method Spur from JB (must be accessible for inspection) Spur from Socket on Ring Legh Richardson

7 Inspection, Testing and Certification (Part 6) Insulation Resistance Testing requires higher values of Resistance between conductors Insulation Resistance test between : P/N PE, P PE, N PE, P N Results must be greater than those given in Table 61 System Volts Test Volts 16 th Ed.Min. 17 th Ed.Min. SELV,PELV 250V 0.25M LV <500V 500V 0.5M LV >500V 1000V 1.0M 0.5M 1.0M 1.0M Legh Richardson 7

8 612.6 Polarity Testing Verify that all functional and protective switching for single pole devices switches in the line conductor only Fuses and Circuit Breakers Functional Switches Line conductor connected to the centre contact in ES fittings (exception being E14 and E27 ES) Socket outlets and SFCU s Phase (Line) Rotation Three phase machinery requires the phases to be ordered due to direction of rotation Legh Richardson 8

9 Automatic Disconnection of Supply Three main systems covered TN, TT, IT TN and TT 1. Earth Fault Loop Impedance 2. Effectiveness of OPD 3. RCD inspect and manual test 4. RCD times to comply with additional protection 5. Verification of Disconnection times IT Systems , c Two simultaneous faults where there is more than one separated circuit connected to more than electrical equipment causing an earth fault to exposed/extraneous conductive parts must be able to disconnect within the times stated for TN systems 2. Measurement of first and second fault conditions Legh Richardson

10 N RCM Warns and Trips on first fault RCM Must disconnect on 2 nd fault - dangerous Legh Richardson

11 Prospective Fault currents 1. Prospective Short Circuit Current 2. Prospective Earth Fault Current 3. Test at the origin for the maximum values and at other relevant points in the installation Use the greater of the two values obtained and compare with the lowest breaking capacity of the protective devices at each point of measurement Three phase supplies may need to measured as a single phase supply and multiplied by ( 2)( Function Testing RCD Test button MCBs Functional switching Contactors, Emergency switching Timers and automatic control systems Volt Drop verification Legh Richardson 11

12 Formula to find the actual Volt Drop when the cable is known: - App 4. 6 V.D Act mv / A / m 1000 Volt drop check by measuring the volt drop while the load is connected and on and measure at: The supply The load The difference being the actual volt drop I B L Legh Richardson

13 Verification of volt drop by Measurement of the circuit impedance i or by calculation Example: The measured Zline for a 9.5kW radial shower unit supplied by a 20m length of 10mm 2 twin and earth cable is The measured external Zline is check the volt drop acceptability for the circuit and verify by calculation 1/ Zl = Zle+R1+Rn (R1+Rn = Zl Zle) R1 Rn Vd Ib (R1 Rn) M Maximum Allowed ; Ib VD Uo 5% P Uo 3. 69V v A 2/ R1+Rn by calculation (Vd = Ib(R1+Rn) R1 Rn 1000 Vd Ib (R1 Rn) V 3/Volt drop formula VD mv /A/ m Ib L V Legh Richardson

14 Example 1. Check that 45m of 1.5mm2 twin and earth cable is suitable for volt drop. Assume a loading of 66% of In at 10A 2. What would be the maximum theoretical loading for compliance with volt Drop using the same parameters in 1.? Legh Richardson

15 Forms changed to reflect changes in definitions Requirement now that documentation is produced for all Installations (132.13) Establishing greater maintainability of installations Portable Appliance testing not within the scope Documentation Provision of manuals and manufacturers data sheet must be included as part of the completion process 610.6, 611.3, , Certification Multiple signatories: Design, Construction and Inspection and Test Single Signature: For all aspects, usually small Installations Minor Works Signatory: Where no circuits have been added Legh Richardson 15

16 Periodic Inspection and Test Non-invasive techniques for inspection and testing preferred Verification of disconnection times as stated in Safety of persons and livestock 2. Protection against damage to property 3. Confirm that installation has not degraded as to effect safe operation 4. Identify defects that are likely to cause danger Verification of Volt Drop 1. By measurement under load ( measure at the origin and at the load for each circuit) 2. By calculation from known factors Legh Richardson 16

17 BS AMD Special Locations or installations Legh Richardson 17

18 Part 7: Special Locations The scope of special locations includes 701: Locations containing a bath or shower 702: Swimming Pools and Other Basins 703: Rooms and Cabins containing Sauna Heaters 704: Construction and Demolition Sites 705: Agricultural and Horticultural Premises 706: Conductive locations with restrictive movement 708: Electrical Installations in Caravan/Caravan Parks and similar locations 709: Marinas and similar locations 710: Medical Locations 711: Exhibitions Shows and Stands 712: Solar Photovoltaic (PV) Power Supply Systems 714: Outside lighting 715: ELV systems 717: Mobile or Transportable Units 721: Electrical Installations in Caravans and Motor Caravans 722: Electric vehicle charging 729: Operating and Maintenance gangways 740: Electrical Installations in Fairgrounds, Amusement Parks and d Circuses 753: Floor and Ceiling Heating Systems Legh Richardson 18

19 Part 7: Special Locations These are deemed to be special because of the greater risks associated with 1. the presence of water, anaesthetics, 2. Low body resistance, low insulation 3. Outside zones of equipotential Bonding, High touch Voltages 4. Access to the general public, unawareness 5. Farm animals and the effects of electric shock 6. Handheld machines (construction sites) 7. Multiple electrical sources of energy 8. Movement, salt water, environmental 9. (restrictive movement, associated with access and service tunnels 10. High breaking capacities and flashover Legh Richardson

20 Location Separation Part 7. Special Locations SELV Double Ins ADS RCD Legh Richardson Heat IP44/ Flash

21 Part 701. Special Locations At a Glance Socket outlets now permitted in bathrooms, (conditionally) No socket outlet within 3 meters of the edge of Zone 1 Must be protected by RCD All circuits in Bathrooms and shower rooms to be protected by RCD this includes under floor heating elements) All current using equipment must be suitable for the Zone or environment, lighting, electric showers, wall heaters, heated mirrors etc. Detachable shower heads extend zone 2 from 0.6m to 1.2m (this still applies) Wet room zone 1 replaces zone 2 to the full 1.2m Legh Richardson 21

22 Part 701. Special Locations Bathrooms and showers Zones Shower with permanently fixed partition Fixed bath tub Legh Richardson

23 Part 701. Special Locations Protection from Electric Shock ( ) Additional Protection Supplementary equipotential bonding to be applied to circuit cpcs and accessible extraneous conductive parts. Including: 1. Metallic service pipes 2. Metallic air conditioning and central heating pipework 3. Accessible structural steelwork, Supplementary bonding can be placed in or adjacent to the bathroom / shower room area (ie airing cupboard next door) Legh Richardson 23

24 Part 701. Special Locations Existing methods of compliance EEBADS via cpc Cross bonding cpcs and extraneous metalwork (increasing R2 csa and reducing touch voltage) RCD additional (supplementary) protection SELV extra low voltage systems Separation (Shaver Sockets) Legh Richardson 24 Legh Richardson

25 Part 7. Special Locations New methods Supplementary equipotential bonding MA be omitted if ALL of the following conditions apply: 1. All final circuits comply with the conditions of (automatic disconnection 0.4s - TN, 0.2s - TT) ADS 2. All final circuits serving the location or/and passing through zones 1 and 2 of that location will have additional protection , (30 ma RCD protected) 3. All extraneous conductive parts are connected to the protective equipotential bonding (This now requires you to measure the effective resistances of the metallic pipework - GN5, GN8) Legh Richardson

26 Part 701. Special Locations simultaneous accessible extraneous parts can be verified by R 50V Ia or 50V I N Ia OPD's I N RCD's OPD or RCD BS EN EN BS EN BS 88 BS 1361 BS 3036 App 3 t/a graphs mA 6A 6A 5A 5A Max Ohms 50/10mA 1667/5,000 GN 5 / GN8 23, Max. time Secs 30A , or A , or A , or A , or 0.4 Protection RCD EEBADS Touch Voltage EEBADS Touch Voltage EEBADS Touch Voltage EEBADS Touch Voltage All circuits in Bathrooms must be protected by an RCD individually ly or in groups Main requirement is that main equipotential bonding is in place and additional protection by 30mA RCD/RCBO for all or each circuit in a bathroom m or shower room. This can be supplemented by localized cross bonding. Legh Richardson

27 Part 701. Special Locations Bathrooms and Showers Minimum Protection = IPX4, exposed to water jets = IPX Switch gear 1. Zone 0 = no switch gear 2. Zone 1 = SELV switches and socket outlets 3. Zone 2 = SELV switches and Socket Outlets, shaver sockets (separated) Socket Outlets are prohibited within 3 m of the boundary of zone 1 Legh Richardson 27