They have a voltage rating, when AC is applied to a perfect capacitor the current leads the voltage by 90° so no heating effect takes place at the rated voltage. Capacitors posses ESR (equivalent series resistance) which will affect the phase angle between voltage and current, the lower the ESR the higher the current, capacitors such as.
Does a capacitor have a current rating?
From the datasheet. Most capacitors don't actually have a "current" rating, since that doesn't make much sense. You can't put a sustained current through a capacitor anyway. If you tried, its voltage would rise linearly, and then you'd get to the voltage limit where you'd have to stop. Put another way, current through a capacitor is inherently AC.
They have a voltage rating, when AC is applied to a perfect capacitor the current leads the voltage by 90° so no heating effect takes place at the rated voltage.
A capacitor will always charge up to its rated charge, if fed current for the needed time. However, a capacitor will only charge up to its rated voltage if fed that voltage directly. A rule of thumb is to charge a capacitor to a voltage below its voltage rating.
This indicates that the rated current of the capacitor must not exceed the ampacity divided by 1.35 to comply with the safety regulations. For example, if the ampacity of a conductor is 100 A, the maximum rated current of the capacitor would be 100 ≈ 74.07. This shows how you can calculate the rated current based on the ampacity provided.
Why does a capacitor have a lower voltage than a lesser resistance?
This is because resistance represents an impedement. It slows down and lessens current, so that charging is slower, and, thus, the resultant voltage across the capacitor will be less than with a lesser resistance. Capacitance, C - C is the capacitance of the capacitor in use.
How to choose a capacitor?
Capacitors can be selected with their rated voltage corresponding to the network voltage. In order to accept system voltage fluctuations, capacitors are designed to sustain over-voltages equal to 1.1 times UN, 8h per 24h. This design margin allows operation on networks including voltage fluctuations and common disturbances.