Wire voltage rating

[baxtersdad]

Given a low voltage cable rated at 600VAC, what would be the maximum allowable DC voltage on which the cable could operate and remain within its design withstand, 600VDC or 850VDC? My question comes from a VFD commom bus application where two drive DC buses are interconnected. A 480VAC VF drive has a dc bus voltage of apx. 680 volts. Must the bus connections be linked with 1000 Volt rated cable or can the 600 volt cable be used under existing codes in the US?

 

[mcgyvr]

600 VDC.

 

[DanDel]

I would say that you must get the DC voltage rating from the manufacturer, if it isn't identified on the cable.

 

[baxtersdad]

Thanks both. Looks like the heating effect is in control...

 

[dpc]

What does the heating effect have to do with the voltage rating?

 

[sslobodan]

Well its 600 V is the voltage limit due to electrical permeability of cable isolation is not changed significantly with DC current. the difference can be calculated, but the answer might be that your cable can take 12V more

And heating has effect on maximum currents, not voltage.