Voltages

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Alwayslearningelec

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NJ
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Estimator
I have a drawing that says "For 600V services use this type wiring..." and "For 208y/120v and 480y/277v use this type wiring..."

How would one tell the difference?? Aren't they one in the same? If you have a 120/208v panel isn't that technically 600v? The same for a 277/480v panel?

Thank you
 
That's a new one to me. The majority of conductors we use have 600v insulation. Type NM cable has 600v insulation. Devices that we use have the voltage rating stamped on them. I'm a little confused too.
 
I have seen a wire called RWU90 that's class B stranding:

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industrial.southwire.com industrial.southwire.com
(I am not sure if its a NEC wire type)
For 600V 'nominal' services they might want a better insulation than 600V.
 
horsegoer said:
How would one tell the difference?? Aren't they one in the same? If you have a 120/208v panel isn't that technically 600v? The same for a 277/480v panel?
Click to expand...

Common building wiring (eg THHN and the like) is rated for 600V, so the only difference I'd expect is something like different color coding for different voltages.

300V flexible cord is often used where 600V isn't needed.

Circuit breakers are certainly rated differently for the different voltages. So I wouldn't say that a 480/277 panel is the same as 208/120. Sometimes the same hardware is used for bus bars and enclosures.

Jon
 
winnie said:
Common building wiring (eg THHN and the like) is rated for 600V, so the only difference I'd expect is something like different color coding for different voltages.

300V flexible cord is often used where 600V isn't needed.

Circuit breakers are certainly rated differently for the different voltages. So I wouldn't say that a 480/277 panel is the same as 208/120. Sometimes the same hardware is used for bus bars and enclosures.

Jon
Click to expand...
I understand wire voltage insulation. My question is determining a source that is 600v as opposed to 120/208v or 277/480v?
 
Your plans should show the service voltage. You could also check the equipment specs.
575/600v isn't common but it is a valid voltage.
As others noted it's almost moot as most conductors are 600v.
 
690Y400V is another standard voltage used in the oil and gas industry, that would require wire rated over 600V. 690V was possibly one of the motivations to move the 600V limits in the nec to 1000V.
 
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