BTS Site Description

Power Distribution

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BTS Site Description

Power Distribution

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1- Power Supply

The three-phase 380V, 50 Hz Alternating current (AC) power should be supplied:

Either directly from the public electricity network (commercial

power supply), or

A derivation from the buildings main distribution panel (with the

agreement of the owner), or From Mobinils own generating plant (generators installed on

site) In case connections to the public electricity network is expected in later stage, the electrical contractor will install provisions for both the generators and the electric company connections.

In all upper cases, this power consumption will be monitored by the means of a power meter.

Before the power is connected to the electrical devices (equipment) and

power sockets the resistance of the grounding system must be in accordance with the Egyptian standards in force and MobiNil requirements. The local power supplier must previously agree to any modification of the multi-grounded neutral in the electrical system.

If a three-phase power supply of 380V is not available, single phase

230V can be used to power the site. For both types of equipment (ALCATEL or MOTOROLA) the power supply in single phase 230V can be used.

The equivalents to all the circuit breakers have to be used to provide a

proper and save working of the site and its equipment. Usually, the preferred 3-phase 380V is currently available in most of the buildings.

For the power supply MobiNil requires 3 phase 380V, 25A per phase for all BTS sites.

BTS Site Description

Power Distribution

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2- Main Power Feeders

All cabling to the shelter shall be through ROXTEC or any other similar product and must be protected by means of a conduit, flame-retardant, and impact protection. The cables shall be installed with a wide radius of curvature. U-clamps shall be used to support the cables every 1-meter of the cable run.

Routing the canalization away from the pedestrians natural

course of circulation, Underground burial of power supplies where feasible (in which

case PVC schedule 40 conduit could be used).

Conduits will be buried at 60 cm below grade minimum with a yellow warning tape.

Where there is car traffic, the depth will be increased to 1 meter. Routing the canalization through existing voids or shafts when

going from ground level to the roof level. The continuity of the main conduit shall be assured. Threaded joints

shall be used (sections, couplings, 90 elbows, etc) to secure an efficient joining between the parts.

3- AC Cables and Wires

All cables should be laid in the cable duct.

Low voltage (220/380 V) and extra low voltage conductors shall not run

in the same conduit, wire duct, or cable tray.

Conductors shall be continuous between devices and no splices shall be

made except within junction boxes.

No cable bend shall have a radius of less than eight times its diameter.

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Power Distribution

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Color Coding shall be as follow:

Phase L1 Phase L2 Phase L3 Neutral Ground

Red Blue Yellow Black Green/Yellow

Receptacle circuits shall not be smaller than 2.5 mm2

Cable trays construction:

Hot dip galvanized manufactured minimum coating thickness is 50 microns, heavy gauge perforated sheet steel minimum thickness 2 mm with not less than 100 mm sides, Fittings to be same material as trays.

Installation: Trays should be fixed using angle brackets at adequate spacing

(8 per shelter).

Sharp edges, burrs, projections and trays finish should being smooth.

Prefabricated elbows (90, 60, 45) to be used at vertical and

horizontal curves with same material and thickness (2mm) of the tray.

Prefabricated cross to be used at the connection between two

or more different direction trays with same material and thickness (2mm) of the tray.

Bends shall be purpose made with radius to permit cable

bending standards

Cable trays cover with thickness 1.5 mm to be installed by squeezing and extra four stainless steel screws at the corner of the tray.

Cables should be secured to trays with specially made ties and

straps

Prefabricated trays should be used in curved joints

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Power Distribution

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The main power cable from source to 100A C.B. and from the 100A C.B.

to the GEDP must be Thermoplastic cable , withstand annealed (Flexible) cupper conductors with PVC insulation, and its size is 3x35mm+1x16mm ( Reduced neutral).

4- Direct current cables (DC)

All cables will be laid in the cable ducts.

Minimum Size not less than 4x35mm2.

Cables for the batteries shall be color coded as follow:

Red for the positive terminal, Black for the negative terminal

All cable trays must be labeled with the cable type AC, DC or signal.

5- Main entrance circuit Breaker A branch circuit breaker shall be installed between the power meter and

the shelters electric panel. The breaker shall have the following characteristics:

100 amp rating, four poles, suitable for 220/380 V

The above breaker shall be enclosed in an enclosure with the following characteristics:

Weatherproof Sheet metal Lockable

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Power Distribution

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6- General Electric Distribution Panel (GEDP)

Downstream of the branch circuit breaker, the main distribution panel is installed inside the shelter next to the entry door. The following branch breakers will be installed in the panel.

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Power Distribution

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A. Green field & indoor (GEDP)

Load of C.B. Rating of C.B. No. of poles Cable CS

Main 63A 4p 4x32mm*2

A/C1 32A 1p 2x6mm*2

A/C2 32A 1p 2x6mm*2

Rectifier 32A 4p 4x6mm*2

Power Socket(Differential)RCCB 16A 2p 2x4mm*2

Power socket 10A 1p 2x4mm*2

Lighting 10A 1p 2x2mm*2

Emergency lighting 10A 1p 2x2mm*2

Fire detection 10A 1p 2x2mm*2

Night beacon 10A 1p 2x2mm*2

Fence lighting 10A 1p 2x2mm*2

A/Cs Control 4A 1p 2x1mm*2

Spare 10A 1p ---

All loads that can be grounded must have additional wire (Grounding

wire of the specified color code). i.e. Sockets, Fire panel, Lighting, ..etc.

The color code must be respected in the inner connections of the

GEDP.

The GEDP must contain two connection bars : A. For the neutral connection of all loads. B. For the earth connection.

Wire of the specified color code). i.e. Sockets , Fire panel , Lighting ,

..etc

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Power Distribution

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Outdoor (GEDP)

Load of C.B. Rating of C.B. No. of poles Cable CS

Main switch 50A 4p 4x32mm*2

CBO for 1 ph source 25A 2p 3x2.5mm*2

MBO for 1ph source 32A 2p 3x6mm*2

MBO for 3ph source 25A 4p 5x6mm*2

Lighting & power outlet 10A 1p 2x2mm*2

Light beacon 10A 1p 2x2mm*2

Fence lights 10A 1p 2x2mm*2

Spare 10A 1p ---

All loads that can be grounded , must have additional wire (Grounding

wire of the specified color code ) . i.e. Sockets, Lighting , ..etc

The fire relay fed by DC voltage from the fire panel must be in the GEDP, with coil rating according to the following table.

Type of fire Panel Fire panel DC voltage Coil rating

Zeta 24 Vdc 24 Vdc PCS 200 24 Vdc 24 Vdc

Esser 12 Vdc 12 Vdc Notes:

All circuit breakers should be labeled with the name of the device they protect. The labeling shall be in a sure and permanent manner.

The electrical diagram should be printed on an aluminum sheet and be

fixed on the GEDP.

All breakers shall have a pole to disconnect the neutral conductor.

Breakers shall be conform to IEC 947-2, NF C 63-120

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Power Distribution

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It is recommended to install a protective device against voltage surges

for the GEDP with a fused protection in accordance with UTE C 15-443 standard The surge limiter shall be in accordance with NF C 61 740 standard with Up>2kV and Imax>40kA (ex: Schneider PF 65r type).

One surge arrestor shall be installed to provide common mode

protection live &neutral wit the following specs :

System rated voltage 220 Volts Rated discharge current 15 KA Full discharge current 40 KA Permanent operating current:

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Power Distribution

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7- Rectifier (elaboration)

In order to convert the alternating current (ac) to direct current (dc) and to charge the batteries a rectifier is installed.

The civil works subcontractor will pull a power supply cable in a duct to

the middle of the future rectifier location about 2,2m above the floor.

The subcontractor will let the cable hanging approximately 1m long from the cable duct in order to connect the rectifier by the BTS manufacturer.

8- BACK UP POWER SUPPLY A set of batteries will be used as a back up power supply of the site in

case of power failure. The set of batteries chosen must be able to supply the site for 8-hours.

The batteries should be placed in the racks (or on tables).

The battery racks should be installed 30cm away from the wall in case of

leakage from the air-conditioning units.

a) For sites equipped by ALCATEL: For 8-hours backup: 3 cabinets Mini BTS (4 TRX per sector) require 48 blocks of batteries placed in 2 racks.

b) For sites equipped by MOTOROLA:

For 8-hours backup: 3 cabinets M-Cell6 (4 TRX per sector) require 5 racks of batteries.

The interconnection for the batteries coupling must be electrically

isolated in accordance with the electrical specifications.

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Power Distribution

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9- General construction Notes 1- Electrical Work Concerning PVC Conduits

All connections and terminations shall be by means of a manufacturers standard adopter. All boxes shall have brass thread inserts for the fixing of accessories or covers. All tees shall be made using conduit tee boxes. Multiple conduits may necessitate the use of large U.P.V.C. adaptable boxes for junctions.

In order to facilitate interchange ability and to eliminate problems of

differential manufacturing tolerances, it is essential that all PVC conduit and appropriate accessories covered by this specification shall be obtained from the same manufacturer.

Conduits shall be joined and terminated utilizing the following

appropriate components as supplied by the conduit manufacturer.

Purposed made adopters and accessories. Permanent adhesive to produce a rigid watertight joint

Conduit shall be supported at intervals of 1 meter.

Multiple conduits may necessitate the use of large PVC adaptable boxes

for junctions, which shall be readily accessible at all times.

All conduits shall have a width of 10cm. 2- Electrical Work Concerning Cables

Where cables are run in cable trays, the cable of each circuit or groups of circuits shall be clipped together using nylon straps or other suitable straps or clips. Were multiple circuits wiring follows a common route then the wiring shall be installed in trucking rather than multiple conduits.

All cable runs shall be continuous and no joints will be permitted.

Individual conductor or circuit identification shall be carried throughout,

with circuit numbers or other identification clearly stamped on terminal boards and printed on directory cards in distribution cabinets and panel

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Power Distribution

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boards. Where terminal boards are not provided, wires shall be properly identified by means of plastic sleeves wire markers

Where cables are supported on cable tray they shall be fixed to the

cable tray using suitable approved straps of clips. Ties shall be spaced at not greater than 600 mm intervals along each cable and within 100 mm of end bend or set.

Conductors shall be sized according to their respective protective

devices and their amp cities. As a guideline, the following excerpts from UTE 15-105 table MS 2A can be followed to determine the minimal conductors size required with respect to the circuit breakers used:

Breaker size Conductor Size (CU)

10 1.5 15 2.5 20 4 32 6 50 10 63 16 80 25 100 35

Installation of Wiring Devices

All wiring shall be fixed independently of the system of wiring. All fixing screws or bolts shall be of steel and where the appropriate apparatus has a protective coating of zinc or is mounted outside; an electro-galvanized finish shall be used complying with relevant standards and codes of practice.

3- Electrical Connections for Equipment

For each electrical connection, provide complete assembly of materials, including but not necessary limited to, pressure connectors, terminals (lugs), electrical insulating tape, electrical solder, electrical soldering flux, heat shrinkable insulating tubing, cable ties, solder less wire nuts, and other items and accessories as needed to complete splices and terminations of type indicated.

Provide electrical, heat-shrinkable insulating tubing boots, solder,

electrical soldering flux, wire nuts and cable ties as recommended for use by the accessories manufacturers for type services indicated.

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Power Distribution

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Connect electrical power supply conductors to equipment conductor in accordance with equipment manufacturers written instructions and wiring diagrams.

Splices insulated by tape shall not be acceptable.

Prepare cables and wires, by cutting stripping covering Armor, jacket,

and insulation properly to ensure uniform and neat appearance where cables and wires are terminated.

Trim cables and wires as short as practicable.

Tighten wire-binding connector screws firmly.

Where a conduit enters a box or other fitting a bushing or grommet shall be

provided to protect the wire from abrasion unless the design of the box or fitting.