Method for Installation of DB or Panel-(Part-2)

METHOD FOR INSTALLATION OF DB OR PANEL-(PART-2)

(4) ELECTRICAL CHECKS BEFORE CHARGING THE PANEL

• TESTING CONTINUITY BETWEEN ALL METAL PARTS AND GROUND * For performing this test, it is generally recommended to use a milliohm meter for continuity measurement. * INSULATION RESISTANCE TESTS For SWITCHGEAR * It is recommended to perform these tests before connection starting so all isolating devices will be closed. * If cables are already connected, open the isolating devices before any test. * Disconnect the ground sensing device and the control cables. * Using a 1000 V DC megohmmeter, measure the insulation resistance after a one minute Electrification time between : * 1) Phase to Phase * 2) Phase to Neutral * 3) Phase to Ground * 4) Ground to Earth * Using a 500 V DC megohmmeter, measure the insulation resistance after a one minute electrification time between: * 1) Auxiliary circuit and ground. * Reconnect the cables after testing. * Control Wiring Electrical Tests for Switchgear and Switchboards * Perform insulation-resistance tests on control wiring with respect to ground. Apply 500 volts dc for 300-volt rated cable and 1000 volts dc for 600-volt rated cable for one minute each. * Important: Units with solid-state components could be damaged if not properly isolated (via removal of plugs and/or fuses) before applying test voltage. Be sure to follow all manufacturers’ recommendations when performing dielectric tests on solid state components * Minimum insulation-resistance values of control wiring should be comparable to previously obtained results but not less than two megohms.

CHARGING & TESTING OF PANEL:

• Cable Terminations: * Identify cable to be laid and Cut the cable to required length. * Put temporary marker onto the cable. * Carefully pull (using suitable method) and lay the cable to its route * Make appropriate opening (Cut-out) in DB /PANEL for inserting the cable with a rubber gasket so that there will be no sharp edges and secure the wire insulation from damage. * Gland the cables using appropriate cable glands size. * Terminate cables inside enclosure by securing cables to switchboards with gland bracket; and enclosure with glanding plates or fabricated steel extension boxes. * Slice the cable and identify cores to be used. Installed the ferrule number and cable lug * Dressing the cable inside the panel and Secure the cables (if necessary) with cable ties or other suitable method * Install cable marker / tag as specified * Terminate the cable properly & as per termination schedule * Earth the glands to the equipment earth grid * After complete termination of wire/cable same DB compartment shall be cleaned and fixed door. * Earthing Connections: * The Panel Main earthing bar is to connected to earth electrode or earthing Grid by Suitable size of 2 No’s of Eathing Strip or Earthing Wire via testing joints. * Energize the Panel * Switch off All Switchgear of Panel. * Connect the incoming cables of Panel to the Power Supply Source. * Check healthy ness of Power Supply at incoming of Panel. * NO LOAD: * Measure input Voltage of Power Supply between Phase to Phase, between Phase and Neutral and between Neutral and Ground. * If measured incoming Voltage is within limit than Switch ON the Main Breaker of Panel. * Measure Voltage on Bus bar between Phase to Phase, between Phase and Neutral and between Neutral and Ground. * If measured Bus bar Voltage is within limit than Panel should operate on NO LOAD Condition for 5 minutes to observe any heating, sparking and performance of accessories of Panel. * After 5 minute, one by one Switch ON the all Circuit Breaker of Panel. * ON LOAD: * Measure Voltage on each outgoing feeder of panel between Phase to Phase, between Phase and Neutral and between Neutral and Ground. * If measured Voltage of outgoing feeders are in within limit than Panel should Energize for 2 hours and verify complete performance. Check for any unusual temperature rise in cables, terminals and protective devices. * Correct Phasing: * Check Phase Sequence of Power Supply at Outgoing Circuit of Panel. * If there is not correct phase sequence for three phase power supply, reverse one phase at incoming side of Panel. * Indicators * Check all Power Supply ON /OFF / TRIP indicator works properly. * If any associated converters check the indications to the corresponding output terminal block. * Under/Overvoltage Protection * Check the relay operation and adjust to the desired rating. * The protection information reports shall be checked up to the distribution board output terminal block. * Automatic Transfer Switches * Check mechanical and / or electrical interlocks. * With the both available supplies (Main Power & D.G Power) confirm the functional checks by presence of voltage, loss of supply, restoration of supply in manual and in automatic mode. * The both incoming supplies are readiness…