Major manufacturers (e.g. www.hubersuhner.com) are providing datasheets that precisely answer your question, both cable and connector related. RG58 low frequency operation voltage is specified as 2.5 kV, test voltage 5 kV rms for 1 min. A good quality still works at 25 kV DC.
Dielectric breakdown is higher than the occurrence of Partial Discharge PD which can occur on long cables. It will become electrostatic, attract dust and even cause contact discharge with charged dust on the insulated sleeve. So test it with an scope probe as an shorted loop antenna around the coax. THere are lots of journal references on this topic.
It will become electrostatic, attract dust and even cause contact discharge with charged dust on the insulated sleeve. So test it with an scope probe as an shorted loop antenna around the coax.