ELECTRICAL CALCULATION SOFTWARE

VOLTAGE DROP & CABLE SIZING PROGRAM

(OVERVIEW)

OVERVIEW

THE OVERALL PROGRAM VIEW

How to used Voltage Drop Calculation Software

TO INDICATE THE CIRCUIT FROM

- The column shall be indicate the name of the Board of the outgoing cable that need to calculate the voltage drop

TO INDICATE THE CIRCUIT GOING TO

- The column shall be indicate the name of the board connected to the cable that need to calculate the voltage drop

MAXIMUM DEMAND

- Maximum demand or the desired power in kW.

SPARE LOAD PER CIRCUIT

- Enter the desired spare power particularly used for sizing the incoming breaker where usually sized for 1.2 times the maximum demand current or if any spare capacity is required.
The total power used for the calculation will be the MD power + spare kW.

VOLTAGE APPLIED

- The voltage that supplied to the system / circuit (currently this software only support 415V)

PHASES

- The system current supply (currently this software only support three phase). So enter �3� in this column.

POWER FACTOR

- The system power factor as Authorities provider (default 0.85)

- For generator set supply shall be 0.8

CABLE LENGTH

- The distance (in meter) from the incoming board to outgoing board

SET VOLTAGE DROP (%)

- Set the desired limit of maximum voltage drop for the cable in percentage.

- The set of voltage drop (the whole system shall be not more than 4% for the particular circuit

TYPE OF CABLE

- Construction of cable to be used

- Cu - Copper

- PVC - PVC cable
PP - PVC/PVC cable
PSP - PVC/SWA/PVC cable
XLP - XLPE/PVC cable
XSP - XLPE/SWA/PVC cable

-          PVC cable - Can be installed in enclosed conduit/trunking (Method 3) or on tray (Method 11).
Available in single core:
     a) For enclosed minimum 1.5mm2 up to 630mm2.
     b) For on tray minimum 25mm2 up to 1000mm2.

-          PVC/PVC Cable - Can be installed in enclosed conduit/trunking (Method 3) or on tray (Method 11).
Available in single core:
     a) For enclosed minimum 1.5mm2 up to 630mm2.
     b) For on tray minimum 25mm2 up to 1000mm2.

-          PVC/SWA/PVC Cable - Limited to install on tray/ladder only ((Method 11).
Available in:
     a) Single core from 50mm2 to 1000mm2.
     b) Four-core from 1.5mm2 to 400mm2.

-          XLPE/PVC Cable - Can be installed in enclosed conduit/trunking (Method 3) or on tray (Method 11).
Available in single core:
     a) For enclosed minimum 1.5mm2 up to 630mm2.
     b) For on tray minimum 25mm2 up to 1000mm2.

-          XLPE/SWA/PVC Cable - Limited to install on tray/ladder only (Method 11).
Available in:
     a) Single core from 50mm2 to 1000mm2.
     b) Fourr-core from 1.5mm2 to 400mm2.

- Nos of cable core to be indicated under column CORE (1/4). Enter 1 for single-core, enter 4 for four-core.

- 1C for single core and 4C for four-core.

CABLE METHOD INSTALLATION

- The way that the cable to be installed / laid.

- a) Enter 3 for enclosed installation, such as in GI conduit/trunking.
b) Enter 11 for installation on tray/ladder flat touching or trefoil.

CABLE PER CIRCUIT

- To indicate cable per phase

-          a) For single-core cable:
     e.g. 1 = 1 cable per phase (total 4 cables)
             2 = 2 cables per phase (total 8 cables)

b) For four-core cable:
     e.g. 1 = 1 No. 4-core cable
             3 = 3 No. 4-core cables

FACTOR TO TAKE CARE

- The factor in the BS standard that considering as follows: -

a. Cg - Grouping derating factor

b. Ca - Ambient temperature derating factor.

- If both Ca and Cg are not entered, then the default derating factor is 0.72

DESIGN CURRENT

- Design Ib � Design or maximum demand current in ampere.

TABULATED CURRENT

- Tabulated It - Required tabulated current-carrying capacity in ampere.

- Ita - Actual tabulated current-carrying capacity (or the current rating of the cable at 30^oC).

- Iz - Effective current-capacity capacity under the prescribed method of installation (Ita x C).

ACTUAL VOLTAGE DROP

- The actual voltage drop for the selected cable in percentage of 415V.

- Max mV/A/m allowed - The mV/A/m of the selected cable shall be less than the max mV/A/m allowed so that the calculated voltage drop will be less than the set %Vd max.

MCCB RECOMMENDATION

- In - Circuit breaker current rating in ampere.

- MCCB - Moulded Case Circuit Breaker manimum size 6A up to 1200A.
(Non IEC ratings are also available).

RECOMEDED SIZE AND NOS OF CABLE

- The programmed will provide automatically the cable size, nos. of cable and method of installation for the calculated circuit to suit the voltage drop set.

Troubleshooting

IMPORTANT NOTE

- a) This program is only applicable to three-phase calculation.
b) Enter data in blue colour areas.
c) Black colour areas are control parameters.
d) Red colour areas are the selected MCCB rating, number and size of selected cables.

CRITERIA

- a) For overload protection: In >= Ib, In =< Iz, Ib =< Iz.

b) For short-circuit protection: In > Iz
c) For normal application, ie overload with short-circuit protection,
use It = In/C.
d) For motor feeder circuit, where MCCB is usually larger to allow for starting current.
Then use It = Ib/C. Additional overload protection device is required.