The cable cross-section depends on several factors.
Domestic Use
For Standard (Domestic) Use
Consider the current rating of the power outlets used: 16 (e.g., Odace S520058), 20, or 32 amps.
For Domestic Applications
Determine the minimum cable cross-section, the number of outlets per circuit breaker, and the maximum rating as specified in the general rules of your standard governing electrical installations.
Other Applications
The elements for determining the cable should be considered in this order:
The First Element: Determine the Outlet to be Installed
To do this, you will need:
- The maximum power consumption of the device to be connected
- The type of network (alternating or direct current) and the voltage values
- The number of connectors: number of phases, neutral, and earth
- The protection rating of the outlet
The protection rating takes into account the environment in which the device is located: exposure to dust and liquids.
Example: I need an outlet for a 28-amp 3-phase compressor with a phase-to-phase voltage of 400V and a neutral connection; I am installing it in an open shelter. The outlet will therefore need a higher rating: 32A 5-pole with IP44 protection (IP rating indicated in C15-103), specifically reference PKF32F435 with a PKZ100 base. The circuit breaker associated with the protection will be a 32A 4p circuit breaker (or 3p+N). For circuit breaker selection, see the paragraph on choosing a circuit breaker.
The Second Element: Type of Cable to be Installed
Consider:
- Multi-conductor or single-conductor cable
- Rigid or flexible construction
- The type of conductor: copper or aluminum
- The type of insulation
Depending on the type of cable to be installed, the cable characteristics will be different, and its current-carrying capacity will vary.
The Third Element: Installation Method
Depending on whether the cable is installed in a conduit or among several cables, it will heat up differently.
With these first three elements, we can predetermine the cable cross-section.
The Final Element: Connection Distance
For devices other than lighting, the voltage drop must not exceed certain limits (for example, in a "yellow tariff" installation, or "monitored tariff" in most cases, the voltage drop must not exceed 3% for lighting and 5% for other applications).
When the voltage drop is too high, the cross-section predetermined using elements a/b/c must be increased so that the voltage drop falls within acceptable limits.
