Cable Size for 3 phase 1250A breaker
- Thread starter aqeelpk
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Hameedulla-Ekhlas
Senior Member
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- AFG
I am not agree with both but wait let me see my documents
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- Lockport, IL
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- Retired Electrical Engineer
Hameedulla-Ekhlas
Senior Member
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Now charlie b,
According to IEC 60502 cable catalog which I had attached in previous post the total ampere capacity of 4 sets 150 mm2 equals to 1412 ampere
According to IEC 60502 catalog, I recommend him to go with 240 mm2 three sets which equals to 1392 ampere.
In this case one set will be deleted.
kingpb
Senior Member
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- SE USA as far as you can go
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- Engineer, Registered
First, 1250A breaker is very standard in IEC equipment.
Second, the cable type, i.e. single core or multi-core makes a huge difference in the ampacity of the cable, and sizes available.
Third, Installation method makes a difference in current carrying capacity, i.e. direct buried, enclosed in conduit, clipped direct to wall, etc.
Fourth, derating is going to be required due to either ground temp, or air temp (depending on installation method) due to what country this is being installed in.
Fifth, what is the duration of short circuit current capability, i.e. 1 sec, 3 sec, etc. This often times increases the cable size.
Sixth, what is the length of the run, VD may be a concern.
Until this information is available, it is not possible to help in deciding what size is needed.
Second, the cable type, i.e. single core or multi-core makes a huge difference in the ampacity of the cable, and sizes available.
Third, Installation method makes a difference in current carrying capacity, i.e. direct buried, enclosed in conduit, clipped direct to wall, etc.
Fourth, derating is going to be required due to either ground temp, or air temp (depending on installation method) due to what country this is being installed in.
Fifth, what is the duration of short circuit current capability, i.e. 1 sec, 3 sec, etc. This often times increases the cable size.
Sixth, what is the length of the run, VD may be a concern.
Until this information is available, it is not possible to help in deciding what size is needed.
aqeelpk
Member
Sorry for late coming again on the forum, i was outside my city.
Cable type is as: 3.5 core, Cu/XLPE/STA/0.6-1Kv/85 degree C rated/burried 1.5mtr under the earth inside 75mm PVC Pipes/ Short circuit capability is 3sec.
And i didn't understand the meaning of length of run and this VD.
Cable type is as: 3.5 core, Cu/XLPE/STA/0.6-1Kv/85 degree C rated/burried 1.5mtr under the earth inside 75mm PVC Pipes/ Short circuit capability is 3sec.
And i didn't understand the meaning of length of run and this VD.
Volta
Senior Member
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- Columbus, Ohio
Voltage Drop over the length of the circuit conductors.
Hameedulla-Ekhlas
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- AFG
It must be per phase voltage drop not phase to phase. Are you sure it is phase to phase?
Hameedulla-Ekhlas
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can you please give me the website address?
Hameedulla-Ekhlas
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let me to mention you one point that the voltage drop is not constant and it changes per load and distance. So, you have to calculate it.
Voltage drop(phase to phase): Since all impedance are per phase and we also calculate the voltage drop per phase not per line.
Hope someone else also give some information regarding to this (phase to phase) voltage drop.
Hi,
this gentleman is not clear about his question.I think he is talking about Medium Voltage not Lv,SO to solve his problem he has to install 3-3*core cu cables in parallel for each phase, because each 3*core cu cable can carry 400amps current.
saffobaba.
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
I interpret "medium voltage" as being above 600 volts, and below 25,000 volts. We are talking about voltages well below 600. So I don't understand your statement.
medium voltage
medium voltage
So for your low voltage system if you have 380/220 or 220/110 Volts for acb you can use 7-1*630 cu cables ( 2 per phase and one neutral). If you have 380/220 V system for load (1250A) you need supply source of 1000KVA and if your system is 220/110 V then for your load (1250A) your supply source must be 500kva.
medium voltage
So for your low voltage system if you have 380/220 or 220/110 Volts for acb you can use 7-1*630 cu cables ( 2 per phase and one neutral). If you have 380/220 V system for load (1250A) you need supply source of 1000KVA and if your system is 220/110 V then for your load (1250A) your supply source must be 500kva.
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