how do i calculate cable size?

Hi,

First you should have the cables manufacrers choosing table, and you should know the type of the cable you must use.i.e. armored or not,3 or 4 cores...itc.

Divide the current amount by (0.85), the new (current) amount use it to find the size of the cable that can Carry this current from the tables.

Also you should considered the voltage drop due to the cable length.i.e the length between the source and the load, there is an equation for the voltage drop calculation.

Hello,

This is a simple question to be answered by any qualified electrician who is authorised or licenced to do this job. Electrical job is to be carried out by licenced person as any wrong execution can kill people. So I do not want to give you any figures. I can give you some advice

1. Current rating of cable will depend on how you lay the cable.

(Underground / in AIR / in duct )

2. What is the ambient temperature.

3. Ground temperature.

4. Depth of laying the cable below ground.

5. Rated maximum temperature rise of the cable.

6 How far is the motor from the starter.

So when you ask this question to an engineer he won't answer as your question is incomplete.

Step by Step Method of Cable Sizing in CR4

Step-1: write down "cable size" on the right side of this page under the heading search this forum.

British Standard 7671 gives full protocols, and is applicable in many jurisdictions. If not applicable, the local protocol will apply.

Of course, an electrical installation needs verification by testing before being energised. This is the domain of the qualified local Electrician who calculates, selects, installs, tests and certifies it as safe, leaving the document with the Client for record-keeping purposes.

So, please delegate the task to such an appropriately-qualified individual, as asking this question reveals a competence shortfall.