5. Sheath voltage to the ground should not exceed 50V.

Chapter 3-2-3 Special Requirements for Power Cable Lines

Article 207. Provisions against Fire

The requirements in this article in Technical RegulationVol.1 and this Guideline is applicable tothe combination of cables connected to a power plant with capacity not less than 25MW, and switch equipment and transformer with voltage from220kV to 500kV as well as special switch equipment and transformer.

Power cable lines shall comply with the following requirements for fire protection.

-In places where power cable lines are linked to switch equipment in closed room, opened switch equipment and cubicles, the lines shall beseparately installed by the wall with flame withstand time not less than 0.75 hours.

-In places where power cable lines are linked to control panel of power plant, the lines shall be protected by the wall with flame withstand time not less than 0.75 hours.

-Cable cellars shall be separated from cable tunnels, cable storey and other cable structures with the wall made of non-flammable materials with flame withstand time not less than 0.75 hours.

-Cable wells shall be equipped with the entry and ladders or hooks for people going up and down.

Article 208. Cable Structures in Power Plants

Power cable lines installed in power plants shall comply with the following requirements.

-Cable structures for cable groups in power plants shall be separately arranged from technical equipment.

-Non-responsible people are prohibited to access to them.

-Cables with flame withstand time not less than 0.25are permitted to be installed in the area of power generators. However, cable structures (oil tank, etc) which might be the source of fire shall be separately arranged by walls with flame withstand time not less than 0.75 hours.

-It is permitted to be installed outside exclusive cable structures only if power cable lines in the area

-A path with flats shall be installed to access power cable lines at the height not less than 5m. The flats of path do not need to be installed for single-core cables or small cable groups up to 20, except the case that they need to be installed for quickreplacement of the lines or the repair during the operation.

- If power cable lines arearranged outside except cable structures inthe area of power generators, the route of the lines shall be selected by ensuring the performance of the cables.

-Cable tunnels and storeys for different cables linked to various power generators shall be divided to units or rooms for cable structures (cable tunnels, storeys, canals, troughs etc.), and sections which cables go through shall be separated by the wall with flame withstand time of 0.75 hours.

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In places where power cable lines traverse compartments or roofs, the location shall be considered the convenience for replacement and installation of additional cables as well as the separating walls made of non-flammable and drillable materials with flame withstand time not less than 0.75 hours.

-In the case that power cable lines in power plants are long, the exits shall be arranged in every 50 m or less.

-Cable group in power plants shall be separately installed by the wall with flame withstand time not less than 0.75 hours from cable tunnels for power cable lines going out the power plants.

Article 209. Spare Cables

Combination of cables (power, control, signal cables, etc.) shall be divided into sub-groups depending on the site conditions and separately arranged each other.

Chapter 3-2-4 Cables Installed Underground

Article 210. Installation Underground

Power cable lines shall be protected from mechanical actions for whole length by the followings.

-The surface of cable canals of power cable lines with voltage lessthan 35kV shall be covered with concrete slabs with the thickness not less than 50mm.

-The surface of cable canals of power cable lines with voltage lessthan 35kV shall be protected with concrete slabs, brick layers linedhorizontally along the lines or other hard materials. (Silica bricks, perforated or hollow bricks are prohibited to use.)

-Underground cables of power cable lines with voltage up to 22kV (except urban area, railways, car

roads, tramways) buried in larger than 1m below the ground level are not required to be protected from mechanical impacts.

Article 211. Depth of Buried Cables

1) The distance from power cable lines with all voltages buried underground to foundations of buildings and construction structures shall not be less than 0.6m.

2)Power cable lines are prohibited to be arranged under foundations of buildings or construction structures. When power cable lines go through underground foundations, the specification of foundations shall comply with promulgated State regulations.

Article 212. Installation Nearby and Crossing Other Cable Lines

When power cable lines with voltage from 110kV to 220kV are arranged with communication lines in parallel, the impact of electro-magnetic fields to the communication lines shall beconsidered, in addition to the distance shown in Table 212 in Technical Regulation.

When power cable lines cross other cable lines, the distance of soil layers between the lines at intersection shall be not less than 0.5m. The distance between power cable lines with voltage up to 35kV and other cable lines are permitted to reduce the distance to 0.15m, if the power cable lines are

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protected by pipes or concrete slabs which are as long as whole intersected section and 1m longer than the section at both sides. Power cables shall be arranged under secondary or communication cables.

As for cable pipes inserted power cable lines and buried underground, the distance between the cable pipes and the distance from the cable pipes to other power bleca lines or other structures,the same values specified for power cable lines without cable pipes. (Refer to 212Tablein Technical Regulation) shall be applied.

When power cable lines are arranged under the floors of workshops, the same values specified for underground power cable lines shall be applied to the distance between the line and the floor.

Article 213. Installation in Parallel to Other Objects

Power cable lines installed in parallel with other objects shall comply with the following requirements and the distance shown in this article in Technical RegulationVol.1.

1. Forest, garden, etc.

In power cable lines traversing the forest or tree planted area, the distance from the lines to the foot of trees shall be not less than 2 m. If local concerned parties agree and the lines insert in cable pipes, above-mentioned distance are permitted to be reduced. Also, in the gardens with small trees, the distance is permitted to be reduced to 0.75 m.

2. Pipelines

Power cable lines are prohibited to be arranged in parallel with the pipelines (water or gas pipeline, etc.) in superposition.

When power cable lines are installed in parallel with heat pipelines, the temperature of ground surrounding the lines shall not be increased exceeding the values in the following table.

Article 214. Crossing Other Objects

Power cable lines cross other objects (railways or car roads, etc.) comply with the following requirements and the distance shown in this article in Technical RegulationVol.1.

-The angle between power cable lines and electrified railway shall be form 75 degrees to 90 degrees.

-Power cable lines installed under the dead-end roads, internal roads of enterprises and exclusive roads with little vehicle traffic are permissible to be installed underground directly.

-Cable blocks and pipes of power cable lines at intersection shall have reserve ones for maintenance. They are sealed at both edges.

-Power cable lines crossed tramways shall be installed in cable blocks or insulated pipes.

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-Power cable lines crossed garages or parking lot shall be installed in cable pipes.

-Power cable lines traversed streams, water canals or alluvial flats shall be installed in cable pipes.

Article 215. Installation of Cable Connection Boxes

Connection boxes of power cable lines shall be installed in compliance with requirements in this article in Technical RegulationVol.1.

Article 216. Protection against Stray Electricity Currents

Power cable lines exposed to stay electricity current dangeroust level shall have the following countermeasures.

-The route of the lines shall be changed to the area with stay electricity current at non-dangerous level.

-In case that the route change is impossible, the lines shall use high anti-corrosion cables or have electrolytic protections shown in the following table.

Article 217. Cable Pipes and Cable Blocks

Cable blocks and pipes of power cable lines shall comply with the following requirements.

-Materials of cable blocks and pipes shall be steels, cast irons, concretes, ceramics, plastic, etc., and be selected in consideration of underground water level, erosion and stray electricity current.

-Each phase of singlecorecables shall be separately arranged in different pipes made ofnon magnetic materials (concrete, etc.).

-The number and dimension of compartment of power cable lines and the distance between compartments shall be selected based on heat condition generated by the current applied to the cable, the ground temperature surrounding the lines, etc. The number of reserved compartment

shall be not less than 15% of all operating ones. (however, the number shall be not less than one.)

-The slope of cable blocks and pipes shall not be less than 0.2%.

-Internal surface of cable blocks, pipes and troughs shall be flat and smooth to avoid the damage of protective covering outer sheaths while pulling cables.

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Article 218. Structures for Cable Arrangement

Cable structures (Cable cellars, blocks and pipes and troughs) for laying and arrangement of power cable lines shall comply with the following requirements.

1.Cable cellars shall be installed to facilitate the laying and connection work of the cables at the following places.

-The points where cables placed in cable blocks change the direction of the route

-The points where cables placed in cable blocks need to connect them including the straight section. (For the positions of cable cellars, refer to item 2 in this article.)

-The points where cables go into the ground from cable blocks.

2.The distance between cable cellars shall be selected based on the permissible cable length for pulling the cable. The permissible cable length shall be considered together with the distance between connection boxes and the position of the boxes. (Refer to article 206 in this Guideline)

3.When the number of power cable lines with voltage up to35kV is 10 or less, it is permissible to penetrate them into the ground from cable blocks directly. In this case, waterproof protection shall be applied to cable blocks.

4.Power cable lines going from cable blocks or pipes to the buildings or tunnels, etc. shall be arranged by the following measures.

-Direct arrangement into the building

-Arrangement in cable cellars or rooms in buildings or near the wall of buildings

5.The measures to prevent the water or small creatures (mouse, snake, etc.) from entering into the buildings or tunnels, etc.

6.In the place with high water level, power cable lines shall be arranged for outdoor distribution substations in troughs or cable boxes shown as below.

-Troughs (including the coves) shall be made of reinforced concrete.

-Troughs shall be arranged on support concrete pillars, and the tilt of troughs shall not be lessthan 0.2%.

-Troughs shall be arranged at the position not to obstruct thetransportation or affect maintenance and operation of other equipment.

7.Cable racks are permitted to be arranged in cable canals in compartment of outdoor distribution

substations. In this case, cables and cubicles do not need to be arranged in cable pipes but protective measures against mechanical action shall be applied to them.

Chapter 3-2-5 Installation of Power Cable Lines in Cable

Structures

Article 219. Reserve Cable Structures

Cable structures shall have the reserve of approximately 15% of designed amount.

Article 220. Requirements for Cable Structures

1. Flame withstand time of cable structure

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Cable structures shall be equipped with support structures with flame withstand time not less than the value shown in Table 220-1.

Table 220-1 Flame withstand time

Cable support structures

Flame-resistant wall separate the compartment and other cable structure in cable tunnel, cellar, corridor, storey and bridge

Door and separating floor for electrical equipment specified in article207 in this Guideline

Door and separating floor except the one mentioned above

Reinforced concrete structure (pole, console)supporting cable storey or outdoor cable corridor

Steel plate supporting cable storey or outdoor cable corridor Cable bridge, cable corridor and support structure Flame-resistant wall to divide into compartment in cable corridor

2. Dimension of cable structure

Cable structures shall be ensured the dimensions shown in the following table.

Table 220-2 Dimension of cable structure

Description of cable structures

The distance between separating walls which divide long cabletunnel for oil-filled cable into sections with a door.

The distance between separating walls which divide long cable tunnel fo cables except oil-filled cable into sections with a door.

The area of cable tunnel with double floor

The distance between entrances of cable bridge or cable rack The distance from the foot of ladder or cable rack to entrance

The distance between entrances of cable corridors which -ofilled cables are installed

The distance between entrances of cable corridor which cables except oil- 150m and less filled cable are installed

The distance of each section of cable corridors which oil-filled cables are installed

The distance of each section of cable corridors which cables except -o 150m and less* filled cable are installed

*Note: Outdoor corridors with closed sections do not need to follow those regulations.

3. Other requirement

1) Entrance and exit

The exits from cable structures shall be installed outward or toward rooms or workshops with fire fighting conditions at high level. The number and position of the exits shall be determined according to site conditions. However, the number shall be not lessthan two. Only one exit ispermitted, if the length of cable structures is not more than 25m.

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The entrance of cable structures shall be selfclosingtype and equipped with the packing. The exits shall be opened outward and be lockable. The exits shall be able to unlock from inside without the key. The doors between compartments of cable tunnel shall be opened toward the nearest exit.

The doors of entrance shall be installed so that strange people can not enter freely. 2) Ladder

Cable bridge and cable rack with technical platform shall equip the ladder for access. 3) Covering slabs

Cable canals and double floors in switch distribution substations or rooms shall be closely covered by removable covering slabs made of non-flammable materials. The covering slabs shall be arranged so that the equipment can be transported. In the hall placed electrical rotating machines, waved steel plates shall be used as the covering slabs.

Article 221. Requirements for Cable Tunnels, Canals and Other Cable Structures

1. Drainage

The slope of the bottoms of cable tunnels and canals toward water pits or water discharge canals shall not be less than 0.5%.

Automatic drainage pumps, which are operated depending on the water level, shall be installed in cable tunnels. Electrical motors and control devices to start equipment shall be able to be operated under wet conditions.

In outside cable canals at higher than underground water level, the bottoms of them are permitted to be constructed by pebble layer with the thickness from 10 to 15 cm paved on the compacted soil.

2. Slope roads

The tilt angle shall not more than 15 degree, whose slope roads are from a compartment to another compartment at different height. The stairs in a compartment of cable tunnels are prohibited to be installed.

The tilt angle of the slope roads betweencable bridges and cable canals shall not be more than 15 degrees. In special cases, Stairs with tilt angle not more than 45 degree are permitted to be installed.

3. Covering slab

The weight of removal covering slabs shall not be more than 50kg. Removal covering slabs shall have hooks to lift them up.

4. Underground cable tunnel

Underground cable tunnels outside of buildings shall be covered by soilayersl with the thickness of 0.5m.

5. Arrangement of other cable

Secondary cables, cables with steel belt of which cross-sectional area is not less than 25mm2, as well as lead sheath cables without steel belt shall be arranged on cable racks in cable structures. Secondary cables without steel belt, lead sheath cables without steel belt and other cables without sheath and of

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which cross-sectional area is less than 16mm2, shall be arranged in troughs or on cable racks separated by plates.

Cable canals installed in the depth not more than 0.9m are permitted to arrange cables at the bottom directly, if one of the following means is applied to them.

- The distance between the group ofcables with voltage exceeding1kV and secondary cable group shall not be less than 100mm.

-Above-mentioned cable group shall be separated by the wall with flame withstand time not less than 0.25 hours.

6.Minimum distance between cables in cable structures

Minimum distance between cables in cable structures shall comply with the values shownthein following table.

Table 221-1 Minimum distance between cables in cable structures

*Note: Above figure applies to underground tunnel with the length not less than 100m in narrow place and with exit at the end and arranged cables with voltage up 10kVto and comply with het distance shown in the following table.

*2Note: Above distance applies to cable racks with effective lengthless than 500mm of support arms at straight routes.

*3Note: Above figure applies to cables with triangle arrangement.

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*4Note: Above distance includes cables arranged in cable wells.

7. Minimum distance from cable rack, cable corridors to building and construction structures

The distance fromcable rack, cable corridors to building and construction structuresshall not less than the values shown in the following table.

Table 221-2 Minimum distances from cable rack, cable corridors to building and construction structures

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Article 222. Prohibition of Installation in Dangerous Places

In places where there is molten metal, liquid, or materials, power cable lines and cable structures shall be installed in compliance with the requirement in this article in Technical RegulationVol.1 for ensuring the safety of them and people.

Article 223. Limitation of Heat Exposure from Heated Pipelines

1. Measures to prevent temperature increase due to heat pipeline

-Thermal insulation materials cover heat pipelines.

-Ventilation in cable structures

2.Limitation of maximum permissible current of cable

If air temperature in cable structures increases after above-mentioned measures are conducted, cable shall be limited the maximum permissible current not to exceed cable permissible temperature.

Article 224. Fire Resistance and Firefighting in Cable Structures

1. Power cable lines installed in cable structures

1) Power cables shall be arranged under secondary cables and communication cables, and be separated by the partitions between power cables and the otherneso. However, the partitions at intersected points and branch points are not required.

2)Power cables with voltage up to 1kV are permitted to be installed next to secondary cables.

3)Power cables with voltage up to1kV shall be arranged over power cableswith voltage exceeding 1kV, and be separated by the partitions between power cables with voltage up 1kVto and power cables with voltage exceeding 1kV.

4)Different power cables with voltage exceeding1kV shall be arranged at different height and be separated by the partitions between them, which are connected to generators, transformers, etc. of the load of category I.

5)Above-mentioned partitions (Item 1), 3), 4)) shall be made of flame-resistant materials with flame withstand time not less than 0.25 hours. In cable canals with automatic fire extinguish systems or water spray systems, above-mentioned partitions (Item 1), 3), 4)) are not required.

6)Cable canals and cable corridors with partially covered do not require above-mentioned partitions (Item 1), 3), 4)). In this case, the distance between reserve cables (except power cables for the load

of category I) shall be not less than 600mm. Cables in cable bridges shall be arranged at both sides of horizontal cable racks of main support structures (beam, hook, etc.), and cables in cable corridors shall be arranged at both sides of passage-way.

2. Requirement for oil-filled cable

Oil-filled cables shall be arranged inseparate cable structures. If oil-filled cables are arranged under

other cables and on horizontal cable racks with flame withstand time not less than 0.75 hours separately. Above-mentioned methods shall be also applied between oil-filled cables.

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