Answer / kashifraza

3-Core Cables:
These cables are used generally for a perfect balanced 3-phase system. When the currents on the 3-live wires of a 3-phase system are equal and at an exact 120° phase angle, then the system is said to be balanced. The 3-phase loads are identical in all respects with no need of a neutral conductor.

3.5-Core Cables:
A 3-phase system may have a neutral wire. This wire allows the 3-phase system to be used at higher voltages while it will still support lower voltage single phase loads.
It is not likely in such cases that the loads will be identical, so the neutral will carry the out-of-balance current of the system. The greater the degree of imbalance, the larger the neutral current.

4-Core Cables:
When there is severe out-of-balance conditions, the amount of fault current will raise to a very high level. Generally in the case of linear loads, the neutral only carries the current due to imbalance between the phases.

Answer / s.ravikumar

THE 3.5 CORE CABLE IS POWER CABLE (NORMALLY HIGH LOAD).
-3 LEADS WILL BE OF SAME SQ.MM
-1 LEADS WILL BE,HALF OF THE ABOVE 3 LEADS
THE 4 CORE CABLE CAN BE USED FOR BOTH POWER AND CONTROL CABLE(NORMALLY LESS LOAD)
-4 CORE WILL BE IN SAME SQ.MM

Answer / kapil tayade

3-Core Cables

These cables are used generally for a perfect balanced 3-phase system. When the currents on the 3-live wires of a 3-phase system are equal and at an exact 120° phase angle, then the system is said to be balanced. The 3-phase loads are identical in all respects with no need of a neutral conductor.

An important example of 3-phase load is electric motor and that is why, they are fed through 3-Core cables in most cases.

3.5-Core Cables

A 3-phase system may have a neutral wire. This wire allows the 3-phase system to be used at higher voltages while it will still support lower voltage single phase loads.

It is not likely in such cases that the loads will be identical, so the neutral will carry the out-of-balance current of the system. The greater the degree of imbalance, the larger the neutral current.



When there is some degree of unbalance and the amount of fault current is very small, then 3.5 core cables are used. In these types of cables, a neutral of reduced cross section as compared to the 3-main conductors is used, which is used to carry the small amount of unbalanced currents.


4-Core Cables

When there is severe out-of-balance conditions, the amount of fault current will raise to a very high level. Generally in the case of linear loads, the neutral only carries the current due to imbalance between the phases.
The non-linear loads such as switch-mode power supplies, computers, office equipment, lamp ballasts and transformers on low loads produce third order harmonic currents which are in the phase of all the supply phases.

These currents do not cancel at the star point of a three-phase system as do normal frequency currents, but add up, so that the neutral carries very heavy third harmonic currents.

Answer / ghulamsarwar3

3.5 MEANS 3CORE AND NEUTRAL IS HALF.4CORE MEANS ALL OF 4
CORE R SAME SIZE.GENERALY WE CAN GET 4CORE UP 25SQMM
CABLE,AFTER 25SQMM 3.5 CORE,NOW A DAYS 1,2,3,4,5,6,7,8
CORES ARE ALSO AVALBLE.

Answer / mukesh kumar

3 core is used for 3-ph loads/systems which do not require
neutral e.g. motors. 3.5/4 core is used wherever 1-ph
supply is also required (tapped between 1ph-N) in addition
to 3 phase supply. 4 core used for smaller cables usually
upto 16 sqmm where neutral core is of same size as phase
cores while 3.5 core is used for higher sizes where neutral
core is half the size of phase cores.

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