Hotel electrical Security Measures. Lightning Protection.
Hotel Lightning Protection drawings have been made.
Electrical Security Measures. Lightning Protection.
The design envisages an earthing system type TC-5 starting from MOB busbars.
Earthing of busbar PE In the main electrical room and in the main distribution board is provided with the help of the external circuit of the earthing device with resistance not greater than 4 Ohm. Busbars PE and N are interconnected in the main distribution board room.
All metal parts of electrical installations normally not under voltage, as well as all metal pipeworks, ductworks, cable trays, ducts, conduits for cable routing, all cabinets of distribution boards and control boards should be earthed.
The Multifunctional complex is subject to protection against lightning, with measures fulfiled for category 2 of norms CO 153-34-21.122-2003.
An overcurrent protective devices and residual current devices (PCD) shall be used for automatic disconnection of supply. Also, PCD shall be used for additional protection against direct contact in final distribution.
Calculation of Earth Termination Network
- Estimated resistivity of top layer of soil: p 1= 300 Ohm*m,
- Estimated resistivity of under layer of soil: p2- 60 Ohm *m,
- Estimated soil resistivity:
р 1- Estimated resistivity of top layer of soil Ohm ‘m, p2- Estimated resistivity of under layer of soil Ohm ‘m, S- Building area, m2; hi- Thickness of top layer of soil, m, a,13- extendable coefficients.
4. Resistivity of concrete foundation (Ohm)
к- Climatic factor;
р- Estimated soil resistivity (Ohm "m);
6. Resistivity of vertical ground:
- Estimated resistivity of horisonfal circuit.
Rn= Rl/kn- 16,9107
Rl-resistivity of horisonfal ground; kn-factor of usage of ground strip;
- Estimated resistivity of electrodes.
Rs- R2/(N‘k3) = 0,55164 ,
R2-resistivity of electrodes; кэ-factor of electrodes usage;
N-electrodes quantity;
Estimated resistivity of earthing circuit:
EARTHING NOTES
- THE EARTHING ТАРЕ AND ALL EXPOSED CONNECTIONS SHALL BE MADE OP 40x4 mm GALVANIZED STEEL TAPE (Ee/Zn). THE DOWNCONDUCTORS ON CONCRETE COLUMNS SHALL BE MADE 0Г 8 mm GALVANISED STEEL ROD.
- ALL CONNECTIONS IN GROUND AND IN CONCRETE SHALL BE WELDED AND CORROSION PROTECTED. ALL CONNECTIONS SHALL BE DONE OVERLAPPED WITH WELDED LENGTH 100mm.
- NEW EARTHING PROTECTION SYSTEM SHALL BE FULLY TESTED. EARTHING RESISTANCE SHALL BE LESS THAN 4 Ohm, OTHERWISE ADDITIONAL VERTICAL GROUNDING ELECTRODES SHALL BE INSTALLED.
- STEEL UTILITIES PIPES SHALL BE CONNECTED TO THE PROTECTIVE EARTHING.
- PROTECTIVE EARTHING PERIMETER CONDUCTOR 40x4mm TO BE INSTALLED AT 1000mm AFEL IN TRANSFORMER ROOM, IN 10kV SWITCHROOM, IN LV SWITCHROOM AND BE CONNECTED TO THE EATHING BUSBAR. ALL OPEN CONDUCTIVE PARTS OF ELECTRICAL EQUIPMENT SHALL BE CONNECTED TO THE PROTECTIVE EARTHING CONDUCTOR.
6. PROTECTIVE EARTHING PERIMETER CONDUCTOR AND MAIN EARTHING BAR IN TRANSFORMER ROOM, IN 10kV SWITCHROOM TO BE DESIGNED BY SUBCONTRACTOR ”SPECENGELECTRO”
- MAIN EARTHING BARS IN 0,4kV SWITCHROOMS ARE BUILT. EARTHING BARS PAINTING SHOULD BE PERFORMED TO THE REQUIREMENTS.
Lightning protection
Lightning protection shall be arranged in accordance with the Instruction on the arrangement of lightning protection of buldings, structures and industrial service (50 153-34.21.122-2003). The buiding shall have category II lightning protection, because a lightning strike may cause damage to electrt and electronic equipment and failure of computers with data loss, which is inadmissible for offices.
A sheet-pie enclosure around the buiding perimeter is used for earthing and also for potential equalization inside the buiding. A llightning arrester 01 made of 8 mm2 diameter steel wire with mesh size of 10 x 10 m shall be placed on the roof of the building. Grll crossing points shall be welded. The Lightning protection mesh should be installed on the root cabling support, or could be installed over the roof stab if flashing and thermal insulation is uninflammable.
Lightning arresters made of 8 mm2 wre shall be laid to the earthing with spans not smaller than Б meters along the buiding perimeter. Place of current drainage wires shall be coordinated with the architects during development of the Working Documentation.
Connections of the lightning arrester grill with current drainage wires and of current drainage wres with earthing bars shall be welded.