1 Core Cable vs. 4 Core Cable

The short answer is yes you can use single core cables instead, but check your electrical standards and local electrical regulations for more details and correct laying, spacing and burying procedures as there are some requirements that differ from using a single 4-core cable.

Additionally there have been some previous threads on CR4 that may be of help, especially when trying to pass three-phase single core cables thru steel (these can be found using the search engine on the right).

thanks a lot for your help.

Yes you can use 4 individual single core cable instead of 4 core cable.

thanks

Selecting and laying power cable for calculated load can be easily refer back to the cable manufacture data sheet. Selecting for the correct and the ways to select the mothod to lays these cable is alwaya depended upon the experiences of the engineering department or the electrical consultant advice.

From your question above, I don't have your total load of your requirements but base on your cables selected of 630 mm² and the distance, I do believed that your total load will be some where about 700 Ampere.

There is two ways that you can do to select your cables.

1) You can use two length per phase of single core cable of 150 mm² where each cable current capacity of 345 Amps. = 690 Amp

Or

2) 2 length of 4 core 240 mm² per phase with each cable current carrying capacity of 360 Amp. = 720 Amp

At the final stage you need to balance up the costing of your projects to see which method is suitable

thanks for suggestion. actually the 630 sq mm cable is for assume design load only. our actual design load but not final yet maybe around 2200 amps @ 380 volt distribution. at 320 meters distance from substation if i use 4 cores cable is very expensive. that is why i am asking for help if posible to use a 1 core cable only which is cheaper compared to 4 cores. considering it will be directly burried to sandy soil here n saudi arabia i worried about the effect to insulation. my other option is to apply to power company to supply us a 13.8 kv feeder near our distribution panel and we will ill use a step down transformer. our request is still under pendingy. our 2nd option is to use the existing substation but the distance is 320 meters

Actually, we can't give you much details on the cables sizes that you will used. Distance is not the problem as there is some calculation, K-factors to be consider and the faults level need to be calculated for the total load connected for the single core cables. In my recently project my cable distance is even longer than your distance that is about 800 meters from the main sub station.

It depends upon your required load. IF you need a very high ampere then, it is better to install a transformer at the site and apply for 13.8KV from your local electricity authorities. It will be much better.

thanks a lot

British Standard 7671 encompasses algorithms that can be used to determine this.

Here in Saudi Arabia though SCECO in Central, Eastern and Western Region have there different standards of installation. As usual practice at MV/LV substations relevant to your distance between SCECO substation to MDB we recommend to use a directly burried 4cores cable type XLPE/CU/PVC/SWA or XLPE/CU/PVC/STA. Neverthelss you can use single core cable provided it must be in PVC conduit sleeve or ducting. Minimum deep of directly burried cable allowed by SCECO is 0.80m for LV and 1.20m for MV. Any LV cable/s in trench entering into the building premises or around the loop outside of the building the minimum distance between the energized cable and telecom cable shall be 0.50m apart.

One option is overhead installation normally 22KV/380V rural tpye. Here in Saudi Arabia it is pretty hard to get the approval from Saudi Consolidated Electricity Company(SCECO) since plenty of justification needs to be done and its a marathon issue. Minimum charge for MV transformer tap at RMU cost us Saudi riyal 125,000. So instead of paying this connection fee , the option is go back to LV underground installation if the distance is minimal.

thanks a lot. your suggestion will be very helpful for my decision later o.