480V on 600v wire

[K2500]

Is 600V rated wire good for 480V? I ask because 480 max. value is about 679V. Do they take that in to acount when they rate the wire?

 

[chris kennedy]

I ask because 480 max. value is about 679V.

Where did you get this from?

 

[benaround]

600vac rated wire is good on any system up to and including 600vac.

 

[infinity]

Where did you get this from?

I would assume he's thinking about peak voltage:

480/.707=678.92 volts

 

[480sparky]

Peak voltage of 480 volts is 679 volts. 480 is the RMS value.

 

[K2500]

I would assume he's thinking about peak voltage:

Correct, so I figured peak voltage is still voltage.

Peak voltage of 480 volts is 679 volts. 480 is the RMS value.

Also correct, but my wire doesn't say RMS, Peak or nominal it just says 600V.

benaround 600vac rated wire is good on any system up to and including 600vac.

Wasn't thinking about 600v systems but peak would be 848.66V. Also an unloaded industrial facility could have a line voltage as high as 620V-630V. That may or may not be O.K., but at the very least seems like it would be pushing it.

 

[Jraef]

Wire insulation voltage ratings are RMS, as are most all AC devices and systems. So 600V rated wire will handle 600V RMS, which would technically be 849V peak, but I don't know of anyone who thinks in terms of peak voltages with AC.

 

[K2500]

Wire insulation voltage ratings are RMS, as are most all AC devices and systems. So 600V rated wire will handle 600V RMS, which would technically be 849V peak, but I don't know of anyone who thinks in terms of peak voltages with AC.

I don't know of anyone who thinks in those terms either, but it was enough to get me wondering.
Thanks for the quick replys.

 

[jim dungar]

I don't know of anyone who thinks in those terms either, but it was enough to get me wondering.
Thanks for the quick replys.

In the NEC definitions, voltage (of a circuit) is defined as RMS.

 

[hdpeng]

In the NEC definitions, voltage (of a circuit) is defined as RMS.

Amen, Jim. Mfg's voltage ratings are for RMS.

 

[steve66]

I agree. Wire labeled 600 VAC is good for 600 volts RMS.

Steve

 

[chris kennedy]

I would assume he's thinking about peak voltage:

480/.707=678.92 volts

Where does the .707 come from?

 

[infinity]

Where does the .707 come from?

Take a look here:

http://www.opamp-electronics.com/tutorials/measurements_of_ac_magnitude_2_01_03.htm

 

[LarryFine]

Where does the .707 come from?

Boeing. :grin:

 

[QES]

I guess we have to use 15 KV cable for 480V system.:smile: