990-91377B-001

Recommended Cable Sizes for IEC

DANGER
hazard of electric shock, explosion, or arc flash
  • All wiring must comply with all applicable national and/or electrical codes.
  • The maximum allowable cable size is 240 mm2.
  • Shrink sleeve must be fitted over cable lug crimped zone and must overlap with the cable insulation on all power cables.
Failure to follow these instructions will result in death or serious injury.

The maximum number of cable connections per busbar:

  • 4 on input/output/bypass busbars

  • 4 x 240 mm2 on input/output/bypass busbars

  • 4 x 240 mm2 or 8 x 150 mm2 on DC+/DC- busbars

  • 8 on N busbar

  • 16 on PE busbar

NOTE: Overcurrent protection is to be provided by others.

Cable sizes in this manual are based on the minimum requirements in table B.52.3 and table B.52.5 of IEC 60364-5-52 with the following assertions*:

  • 90 °C conductors

  • An ambient temperature of 30 °C

  • Use of copper or aluminum conductors

  • Installation method F

  • Single layer on a perforated cable tray

PE cable size is based on table 54.2 of IEC 60364-4-54.

If the ambient temperature is greater than 30 °C, larger conductors are to be selected in accordance with the correction factors of the IEC.

Copper

UPS rating 200 kW 250 kW 300 kW 350 kW
Voltage (V) 380 400 415 440 380 400 415 440 380 400 415 440 380 400 415 440
Input phases (mm2) 1 x 120 1 x 120 1 x 120 1 x 120 1 x 185 1 x 185 1 x 150 1 x 150 1 x 240 1 x 240 1 x 240 1 x 185 2 x 120 2 x 120 2 x 120 1 x 240
Input PE (mm2) 1 x 70 1 x 70 1 x 70 1 x 70 1 x 95 1 x 95 1 x 95 1 x 95 1 x 120 1 x 120 1 x 120 1 x 95 1 x 120 1 x 120 1 x 120 1 x 120
Bypass/output phases (mm2) 1 x 95 1 x 95 1 x 95 1 x 95 1 x 150 1 x 120 1 x 120 1 x 120 1 x 185 1 x 150 1 x 150 1 x 150 1 x 240 1 x 240 1 x 185 1 x 185
Bypass PE/output PE (mm2) 1 x 50 1 x 50 1 x 50 1 x 50 1 x 95 1 x 70 1 x 70 1 x 70 1 x 95 1 x 95 1 x 95 1 x 95 1 x 120 1 x 120 1 x 95 1 x 95
Neutral (mm2) 1 x 95 1 x 95 1 x 95 1 x 95 1 x 150 1 x 120 1 x 120 1 x 120 1 x 185 1 x 150 1 x 150 1 x 150 1 x 240 1 x 240 1 x 185 1 x 185
DC+/DC- (mm2) 1 x 185 1 x 240 2 x 150 2 x 185
DC PE (mm2) 1 x 95 1 x 120 1 x 150 1 x 185
Inverter midpoint cable for 3-wire parallel (mm2) 1 x 120 1 x 120 1 x 120 1 x 120 1 x 185 1 x 185 1 x 150 1 x 150 1 x 240 1 x 240 1 x 240 1 x 185 2 x 120 2 x 120 2 x 120 1 x 240

Copper

UPS rating 400 kW 450 kW 500 kW
Voltage (V) 380 400 415 440 380 400 415 440 380 400 415 440
Input phases (mm2) 2 x 150 2 x 150 2 x 150 2 x 150 2 x 240 2 x 240 2 x 185 2 x 150 2 x 240 2 x 240 2 x 240 2 x 240
Input PE (mm2) 1 x 150 1 x 150 1 x 150 1 x 150 1 x 240 1 x 240 1 x 185 1 x 150 1 x 240 1 x 240 1 x 240 1 x 240
Bypass/output phases (mm2) 2 x 120 1 x 240 1 x 240 1 x 240 2 x 150 2 x 150 2 x 120 1 x 240 2 x 185 2 x 150 2 x 150 2 x 150
Bypass PE/output PE (mm2) 1 x 120 1 x 120 1 x 120 1 x 120 1 x 150 1 x 150 1 x 120 1 x 120 1 x 185 1 x 150 1 x 150 1 x 150
Neutral (mm2) 2 x 120 1 x 240 1 x 240 1 x 240 2 x 150 2 x 150 2 x 120 1 x 240 2 x 185 2 x 150 2 x 150 2 x 150
DC+/DC- (mm2) 2 x 240 3 x 150 3 x 185
DC PE (mm2) 1 x 240 2 x 120 2 x 150
Inverter midpoint cable for 3-wire parallel (mm2) 2 x 150 2 x 150 2 x 150 2 x 150 2 x 240 2 x 240 2 x 185 2 x 150 2 x 240 2 x 240 2 x 240 2 x 240

Aluminum

UPS rating 200 kW 250 kW 300 kW 350 kW
Voltage (V) 380 400 415 440 380 400 415 440 380 400 415 440 380 400 415 440
Input phases (mm2) 1 x 185 1 x 185 1 x 185 1 x 185 2 x 120 2 x 120 1 x 240 1 x 240 2 x 150 2 x 150 2 x 150 2 x 120 2 x 185 2 x 185 2 x 185 2 x 150
Input PE (mm2) 1 x 95 1 x 95 1 x 95 1 x 95 1 x 120 1 x 120 1 x 120 1 x 120 1 x 150 1 x 150 1 x 150 1 x 120 1 x 185 1 x 185 1 x 185 1 x 150
Bypass/output phases (mm2) 1 x 150 1 x 150 1 x 150 1 x 120 1 x 185 1 x 185 1 x 185 1 x 185 2 x 120 1 x 240 1 x 240 1 x 240 2 x 150 2 x 150 2 x 120 2 x 120
Bypass PE/output PE (mm2) 1 x 95 1 x 95 1 x 95 1 x 70 1 x 95 1 x 95 1 x 95 1 x 95 1 x 120 1 x 120 1 x 120 1 x 120 1 x 150 1 x 150 1 x 120 1 x 120
Neutral (mm2) 1 x 150 1 x 150 1 x 150 1 x 120 1 x 185 1 x 185 1 x 185 1 x 185 2 x 120 1 x 240 1 x 240 1 x 240 2 x 150 2 x 150 2 x 120 2 x 120
DC+/DC- (mm2) 2 x 120 2 x 150 2 x 240 3 x 150
DC PE (mm2) 1 x 120 1 x 150 1 x 240 2 x 120
Inverter midpoint cable for 3-wire parallel (mm2) 1 x 185 1 x 185 1 x 185 1 x 185 2 x 120 2 x 120 1 x 240 1 x 240 2 x 150 2 x 150 2 x 150 2 x 120 2 x 185 2 x 185 2 x 185 2 x 150

Aluminum

UPS rating 400 kW 450 kW 500 kW
Voltage (V) 380 400 415 440 380 400 415 440 380 400 415 440
Input phases (mm2) 2 x 240 2 x 240 2 x 240 2 x 240 (3 x 185)* (3 x 185)* 2 x 240 2 x 240 (3 x 185)* (3 x 185)* (3 x 185)* (3 x 185)*
Input PE (mm2) 1 x 240 1 x 240 1 x 240 1 x 240 2 x 150 2 x 150 1 x 240 1 x 240 2 x 150 2 x 150 2 x 150 2 x 150
Bypass/output phases (mm2) 2 x 185 2 x 150 2 x 150 2 x 150 2 x 240 2 x 240 2 x 185 2 x 150 2 x 240 2 x 240 2 x 240 2 x 240
Bypass PE/output PE (mm2) 1 x 185 1 x 150 1 x 150 1 x 150 1 x 240 1 x 240 1 x 185 1 x 150 1 x 240 1 x 240 1 x 240 1 x 240
Neutral (mm2) 2 x 185 2 x 150 2 x 150 2 x 150 2 x 240 2 x 240 2 x 185 2 x 150 2 x 240 2 x 240 2 x 240 2 x 240
DC+/DC- (mm2) 3 x 185 3 x 240 4 x 185
DC PE (mm2) 2 x 150 2 x 185 2 x 185
Inverter midpoint cable for 3-wire parallel (mm2) 2 x 240 2 x 240 2 x 240 2 x 240 3 x 185 3 x 185 2 x 240 2 x 240 3 x 185 3 x 185 3 x 185 3 x 185

Guidance for Organizing Input, Bypass, And Output Cables

The input, bypass, and output cables must be grouped in circuits. On raceways, use one of the two shown cable formations.

Load Sharing in Bypass Operation in a Parallel System

The impedance of the bypass paths need to be controlled in a parallel UPS system. When operating in bypass mode, the parallel load sharing is determined by the total impedance of the bypass path comprising cables, switchgear, static bypass switch, and cable formation.

Parallel System – Dual Mains

NOTICE
Risk of equipment damage
To ensure correct load sharing in bypass operation in a parallel system, the following recommendations apply:
  • The bypass cables must be the same length for all UPSs.
  • The output cables must be the same length for all UPSs.
  • The input cables must be the same length for all UPSs in a single mains system.
  • Cable formation recommendations must be followed.
  • The reactance of busbar layout in the bypass/input and output switchgear must be the same for all UPSs.
If the above recommendations are not followed the result can be uneven load sharing in bypass and overload of individual UPSs.
Failure to follow these instructions can result in equipment damage.

ECOnversion Limits for Parallel UPS Systems

ECOnversion requires a minimum load percentage on the UPS for parallel UPS systems. The minimum required load percentages depend on the power cable sizes.

NOTE: For installations using the recommended cable sizes, refer to the Standard ECOnversion Limits Based on Recommended Cable Sizes table for the minimum load percentages.

Standard ECOnversion Limits Based on Recommended Cable Sizes

UPS rating Minimum load %
200 kW 34%
250 kW 27%
300 kW 23%
350 kW 19%
400 kW 17%
450 kW 15%
500 kW 14%

The other prerequisites to use this table include:

  • The values are calculated based on the use of recommended cable sizes.

  • Installations with maximum two cables on each phase are supported.

  • The bypass and output cables must have equal length for all UPSs.


NOTE: For certain installations such as installations with 80% breakers or where other installation methods have been applied to comply with the IEC standard, it is possible that non-recommended cable sizes will be used. For installations using non-recommended cable sizes, refer to the Standard ECOnversion Limits Based on Non-recommended Cable Sizes table for the voltage ratings percentages.

Standard ECOnversion Limits Based on Non-recommended Cable Sizes

UPS rating Minimum load %
200 kW 50%
250 kW 40%
300 kW 34%
350 kW 29%
400 kW 25%
450 kW 22%
500 kW 20%

The other prerequisites to use this table include:

  • The values are calculated based on the scenario of using non-recommended cable sizes.

  • Installations with three or four cables on each phase are supported.

  • The bypass and output cables must have equal length for all UPSs.

For 3-Wire Parallel Systems Only

In a parallel installation installed as a 3-wire AC configuration, the inverter midpoint of each UPS must be interconnected by cable in a daisy chain configuration. The inverter midpoint cable size can be found in the recommended cable sizes table.

When the inverter midpoint of the parallel UPSs is permanently connected, there is still potentially dangerous voltage present on the neutral busbar inside the UPS even after the UPS has been isolated from the parallel system for maintenance and has been completely shut down. Due to the dangerous voltages on the neutral busbar, all service activities that need access inside the I/O section by opening the inner door require full shutdown of the entire parallel system and transfer to maintenance bypass.

DANGER
Hazard of electric shock, explosion, or arc flash
  • Hard-wired inverter midpoint between the UPS systems is energized even when the UPS is isolated from the parallel system and completely shut down.
  • Even if absence of voltage is measured, there can still be dangerous voltage transients on the neutral busbar.
  • Entering the I/O terminal area requires full shutdown or the entire parallel system and transfer to maintenance bypass.
Failure to follow these instructions will result in death or serious injury.
NOTE: For 3-wire parallel systems that have neutral available from the input source, the parallel system can be installed as a 4-wire AC configuration, which does not require the inverter midpoint connection between each UPS. Contact Schneider Electric for more details.

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