Table of Contents
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Power cables of the charging stations are connected to the common point (electrical cabinet in the following figure).
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Figure 7: Cluster cabling route for multiple charging stations - star network topology
Power cables Point to Point Network Topology
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In case that Point-to-Point communication is needed for the power supply, all INCH Duo’s of the cluster with exclusion of the last one, should be equipped with double terminal clamps.
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Figure 8: Cluster cabling route - point to point network topology (daisy chain)
Power cables Hybrid Network Topology
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Cluster of charging stations can be connected to the network with UTP cable or with ADSL cable over Wi-Fi to the existing ethernet network, or ethernet network can be created only for the charging stations.
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All the charging stations of the cluster need to be connected to the network. The communication cables should follow star network topology. Point-to-Point wiring of communication cables is not fully supported yet. When needed all INCH Duo’s of the cluster should be equipped with router.
Table 6: Power cables installation method
  | A1 - Insulated single core conductors in conduit in a thermally insulated wall A2 - Multicore cable in conduit in a thermally insulated wall This method also applies to single core or multicore cables installed directly in a thermally insulated wall (use methods A1 and A2 respectively), conductors installed in mouldings, architraves, and window frames.
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  | B1 - Insulated single core conductors in conduit on a wall B2 - Multicore cable in conduit on a wall This method applies when a conduit is installed inside a wall, against a wall or spaced less than 0.3 x D (overall diameter of the cable) from the wall. Method B also applies for cables installed in trunking / cable duct against a wall or suspended from a wall and cables installed in building cavities.
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  | C - Single core or multi-core cable on a wooden wall This method also applies to cables fixed directly to walls or ceilings, suspended from ceilings, installed on unperforated cable trays (run horizontally or vertically), and installed directly in a masonry wall (with thermal resistivity less than 2 K·m/W).
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  | D1 - Multicore or single core cables installed in conduit buried in the ground D2 - Multicore or single core cables buried directly in the ground |
  | E - Multicore cable in free-air This method applies to cables installed on cable ladder, perforated cable tray or cleats provided that the cable is spaced more than 0.3 x D (overall diameter of the cable) from the wall. Note that cables installed on unperforated cable trays are classified under Method C.
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  | F - Single core cables touching in free-air This method applies to cables installed on cable ladder, perforated cable tray or cleats provided that the cable is spaced more than 0.3 x D (overall diameter of the cable) from the wall. Note that cables installed on unperforated cable trays are classified under Method C.
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 | G - Single-core cables laid flat and spaced in free-air This method applies to cables installed on cable ladder, perforated cable tray or cleats provided that the cable is spaced more than 0.3 x D (overall diameter of the cable) from the wall and with at least 1 x D spacings between cables. Note that cables installed on unperforated cable trays are classified under Method C. This method also applies to cables installed in air supported by insulators. |
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The currents presented in the following table require additional considerations from the electrical works planning view, which should be determined in the electrical project. It is possible, that high charging current would require implementation of bus-bar systems and/or possible installation of power transformers and/or additional requirements from the view of electrical safety and documentation preparation.
Table 7: Considering maximal current in case of clusters
Number of INCH DUO | Number of electric vehicles | Max. charging current (per phase) | Maximal charging power |
5 | 10 | 320 A | 220,8 kW |
10 | 20 | 640 A | 441,6 kW |
15 | 30 | 960 A | 662,4 kW |
20 | 40 | 1280 A | 883,2 kW |
25 | 50 | 1600 A | 1104 kW |
30 | 60 | 1920 A | 1324,8 kW |
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Almost all vehicles require minimally 6 A of charging current. Considering that there are some vehicles that require higher minimal charging current, some reserve to the numbers in the following table should be added to ensure all connected vehicles can charge simultaneously.
Table 8: Considering minimal current in case of clusters (three-phase wiring)
Number of INCH DUO | Number of electric vehicles | Min. charging current (per phase) | Maximal charging power |
5 | 10 | 60 A | 41,4 kW |
10 | 20 | 120 A | 82,8 kW |
15 | 30 | 180 A | 124,2 kW |
20 | 40 | 240 A | 165,6 kW |
25 | 50 | 300 A | 207 kW |
30 | 60 | 360 A | 248,4 kW |
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Three-phase system with copper conductors with XLPE insulation
Ambient temperature 35 °C
Ground temperature 25 °C
Thermal resistivity of the soil 2,5 K·m/W
Table 9: Minimal cables cross-sections under specified conditions (1/2)
Current of the cluster | [A] | 32 | 64 | 96 | 128 | 160 | 192 | 224 |
Method of installation | A1 [mm] | 6 | 16 | 35 | 50 | 70 | 95 | 120 |
Method of installation | A2 [mm] | 6 | 16 | 35 | 70 | 95 | 120 | 150 |
Method of installation | B1 [mm] | 4 | 16 | 25 | 35 | 50 | 70 | 95 |
Method of installation | B2 [mm] | 4 | 16 | 25 | 50 | 70 | 95 | 120 |
Method of installation | C [mm] | 4 | 10 | 25 | 35 | 50 | 70 | 95 |
Method of installation | D1 [mm] | 4 | 16 | 35 | 50 | 70 | 120 | 150 |
Method of installation | D2 [mm] | 4 | 16 | 25 | 50 | 70 | 95 | 120 |
Method of installation | E [mm] | 2,5 | 10 | 16 | 25 | 35 | 50 | 70 |
Method of installation | F [mm] | 25 | 25 | 25 | 25 | 35 | 50 | 50 |
Method of installation | G [mm] | 25 | 25 | 25 | 25 | 25 | 35 | 50 |
Table 10: Minimal cables cross-sections under specified conditions (2/2)
Current of the cluster | [A] | 256 | 288 | 320 | 352 | 384 | 416 | 448 |
Method of installation | A1 [mm] | 150 | 185 | 240 | 240 | 300 | 300 | X |
Method of installation | A2 [mm] | 185 | 240 | 240 | 300 | X | X | X |
Method of installation | B1 [mm] | 95 | 120 | 150 | 185 | 240 | 240 | 300 |
Method of installation | B2 [mm] | 120 | 185 | 185 | 240 | 300 | 300 | X |
Method of installation | C [mm] | 95 | 120 | 150 | 150 | 185 | 240 | 240 |
Method of installation | D1 [mm] | 185 | 240 | 300 | X | X | X | X |
Method of installation | D2 [mm] | 150 | 185 | 240 | 240 | 300 | X | X |
Method of installation | E [mm] | 70 | 95 | 95 | 120 | 120 | 150 | 150 |
Method of installation | F [mm] | 70 | 70 | 95 | 95 | 120 | 150 | 150 |
Method of installation | G [mm] | 50 | 70 | 70 | 95 | 95 | 120 | 120 |
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Voltage drop in the power cable is proportional to the current of the load. When installing two INCH DUO charging stations, also voltage drops are twice as high as in case of one INCH DUO without considering any additional elements.
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Figure 9: Cluster cabling route length
The voltage drop presented in the tables are calculated for single-phase and three-phase connection. Although the connection of INCH DUO is almost always three-phase, using values of voltage drop in single-phase can represent beneficial reserve when planning the correct cable cross-section.
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Charging current 128 A (Two INCH DUO with max. current) | Conductor 35 mm2 Single phase | Conductor 35 mm2 Three phase |
L - length [m] | Voltage drop [%] | Voltage drop [%] |
40 | 2,62 | 2,27 |
50 | 3,28 | 2,84 |
60 | 3,93 | 3,40 |
Table 12: Voltage drop in conductors with 50 mm2 cable cross-section and charging current of 128 A.
Charging current 128 A (Two INCH DUO with max. current) | Conductor 50 mm2 Single phase | Conductor 50 mm2 Three phase |
L - length [m] | Voltage drop [%] | Voltage drop [%] |
60 | 2,84 | 2,46 |
70 | 3,31 | 2,87 |
80 | 3,78 | 3,27 |
90 | 4,25 | 3,68 |
For example, looking at the table determining minimal cross-section of cables for maximal continuous current of 320 A, depending on the installation method, either 70 mm2 (Method G) or 150 mm2 (Method C) cables could be used when connecting 5 INCH DUO charging stations with maximum charging current available. Reviewing the selection of the cable with consideration of voltage drop, shows that allowable distance of conductors is a lot lower than if selecting higher cable cross-section.
Table 13: Voltage drop in conductors with 70 mm2 cable cross-section and charging current of 320 A.
Charging current 320 A (Five INCH DUO with max. current) | Conductor 70 mm2 Single phase | Conductor 70 mm2 Three phase |
L - length [m] | Voltage drop [%] | Voltage drop [%] |
40 | 3,51 | 3,04 |
50 | 4,39 | 3,80 |
Table 14: Voltage drop in conductors with 95 mm2 cable cross-section and charging current of 320 A.
Charging current 320 A (Five INCH DUO with max. current) | Conductor 95 mm2 Single phase | Conductor 95 mm2 Three phase |
L - length [m] | Voltage drop [%] | Voltage drop [%] |
30 | 2,03 | 1,76 |
40 | 2,71 | 2,35 |
50 | 3,39 | 2,93 |
60 | 4,06 | 3,52 |
Table 15: Voltage drop in conductors with 120 mm2 cable cross-section and charging current of 320 A.
Charging current 320 A (Five INCH DUO with max. current) | Conductor 120 mm2 Single phase | Conductor 120 mm2 Three phase |
L - length [m] | Voltage drop [%] | Voltage drop [%] |
50 | 2,80 | 2,43 |
60 | 3,36 | 2,91 |
70 | 3,93 | 3,40 |
80 | 4,49 | 3,88 |
Table 16: Voltage drop in conductors with 150 mm2 cable cross-section and charging current of 320 A.
Charging current 320 A (Five INCH DUO with max. current) | Conductor 150 mm2 Single phase | Conductor 150 mm2 Three phase |
L - length [m] | Voltage drop [%] | Voltage drop [%] |
40 | 1,89 | 1,64 |
50 | 2,36 | 2,04 |
60 | 2,83 | 2,45 |
70 | 3,30 | 2,86 |
80 | 3,78 | 3,27 |
90 | 4,25 | 3,68 |
Table 17: Voltage drop in conductors with 240 mm2 cable cross-section and charging current of 320 A.
Charging current 320 A (Five INCH DUO with max. current) | Conductor 240 mm2 Single phase | Conductor 150 mm2 Three phase |
L - length [m] | Voltage drop [%] | Voltage drop [%] |
80 | 2,71 | 2,35 |
90 | 3,05 | 2,64 |
100 | 3,39 | 2,94 |
110 | 3,73 | 3,23 |
120 | 4,07 | 3,52 |
Table 18: Voltage drop in conductors with 300 mm2 cable cross-section and charging current of 320 A.
Charging current 320 A (Five INCH DUO with max. current) | Conductor 300 mm2 Single phase | Conductor 300 mm2 Three phase |
L - length [m] | Voltage drop [%] | Voltage drop [%] |
100 | 2,95 | 2,55 |
110 | 3,24 | 2,81 |
120 | 3,54 | 3,06 |
130 | 3,83 | 3,32 |
140 | 4,13 | 3,57 |
There are several options considering larger distances of cable path and larger charging currents. The main conductor could have larger cross-section, that could be distributed through junction boxes, each connecting small cluster. The use of busbar trunking systems could be beneficial.
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Although the short circuit withstand criterion must be evaluated when dimensioning cables cross-section, in practice requirements of the first two criteria are stricter (continuous operating current and voltage drop).
Table 19: Minimum cable cross-section able to withstand specified short circuit
Short circuit | Initial temperature 65 ° C | Initial temperature 35 ° C | ||
XLPE, copper | PVC, copper | XLPE, copper | PVC, copper | |
2 kA, 10 ms | 1,28 mm2 | 1,69 mm2 | 1,16 mm2 | 1,43 mm2 |
2 kA, 20 ms | 1,81 mm2 | 2,39 mm2 | 1,63 mm2 | 2,03 mm2 |
3 kA, 10 ms | 1,91 mm2 | 2,53 mm2 | 1,73 mm2 | 2,15 mm2 |
3 kA, 20 ms | 2,71 mm2 | 3,58 mm2 | 2,45 mm2 | 3,04 mm2 |
5 kA, 10 ms | 3,19 mm2 | 4,22 mm2 | 2,89 mm2 | 3,58 mm2 |
5 kA, 20 ms | 4,51 mm2 | 5,96 mm2 | 4,09 mm2 | 5,07 mm2 |
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Keep in mind that if the cables cross-section changes (e.g., in first junction box, from cross-section used on L1 to cross-section used on L2) and is lowered to level that cannot sustain the full current, the over-current protection element should be installed.
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Figure 10: Example of INCH DUO connection – standard configuration
Maximal continuous current of the cluster
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Voltage drop in cable at L1
Table 20: Voltage drop in conductors with 400 mm2 cable cross-section and charging current of 960 A.
Charging current | Conductor | Conductor |
960 A | 400 mm2 | 400 mm2 |
| Single phase | Three phase |
Distance [m] | Voltage drop [%] | Voltage drop [%] |
10 | 0,75 | 0,65 |
20 | 1,50 | 1,30 |
30 | 2,25 | 1,95 |
40 | 3,00 | 2,60 |
50 | 3,75 | 3,25 |
60 | 4,51 | 3,90 |
For 960 A and copper conductors with cross-section of 400 mm2, the voltage drop is quite large, indicating the possible need of more main power cable routes or need for limitation of maximal charging current.
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The case presented in the following figure is possible only with double clamp terminals installed in all INCH DUO charging stations, instead of the last one of the power lines (three INCH DUOs that are completely right on the figure). The cable cross-sections must be determined in accordance with all three criteria.
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Figure 11: Example of INCH DUO connection – use of double terminal clamps
Maximal continuous current of the cluster
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Case 3: Power Cables for Cluster of 15 INCH DUO in Expanded Point to Point Network
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Figure 12: Example of INCH DUO connection – use of double terminal clamps
The figure presented above is showing possible selected configuration, after reviewing Case 1 and 2. It could be more expensive to install three main routes of cables, however using more conductive material (copper) will lower the voltage drop of installation (and with it the power losses).
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