Minimum voltage rating on breaker

[mull982]

What is the minimum voltage rating you can use for a circuit breaker at a given voltage?

I think there was a rule I heard that it cannot be rated any less then the L-G voltage of the particular voltage it was being used on?

For example can a 120V breaker be used on a 480V circuit? From what I heard above it sounds like the breaker would have to be rated for at least 277V to be used on 480V?

However a 120V circuit breaker can be used on a 240V circuit because L-G on 240V circuit is 120V.

 

[zog]

What is the minimum voltage rating you can use for a circuit breaker at a given voltage?

I think there was a rule I heard that it cannot be rated any less then the L-G voltage of the particular voltage it was being used on?

For example can a 120V breaker be used on a 480V circuit? From what I heard above it sounds like the breaker would have to be rated for at least 277V to be used on 480V?

However a 120V circuit breaker can be used on a 240V circuit because L-G on 240V circuit is 120V.

The breaker has to be rated at the voltage you are applying it to. They have to interupt phase to phase faults.

 

[Hameedulla-Ekhlas]

What is the minimum voltage rating you can use for a circuit breaker at a given voltage?

I think there was a rule I heard that it cannot be rated any less then the L-G voltage of the particular voltage it was being used on?

For example can a 120V breaker be used on a 480V circuit? From what I heard above it sounds like the breaker would have to be rated for at least 277V to be used on 480V?

However a 120V circuit breaker can be used on a 240V circuit because L-G on 240V circuit is 120V.

The voltage rating of a fuese or circuit breaker is the highest voltage that is capable of safely interrupting under all overload and short circuit conditions for which it is rated to interrupt. In order for an overcurrent protective device to operate correctly based on its voltage rating, that rating has to be to or greater than the system voltage and for example, you can use a 600 volt fuse or circuit breaker in a 577 V, 480 V or 120 V circuit, but a 250 volt fuse or circuit breaker would not meet NEC standards if you wanted to install it for a 480 V or 277 V circuit. There are two physical aspects to the operation of voltage rated overcurrent protection device. The first is that it must have sufficient creepage and clearance distances to eliminate any conductive path or flashover between conductive parts of different phases such as phase to neutral or phase to ground.

Nex, the OCPD voltage rating is also a function of its capacity to open a circuit under an overcurrent condition, and it determines the ability of the overcurrent protection device to suppress and snuff out the interal arcing that occurs during an overcurrent condition. If an OCPD with a voltage rating lower than the circuit votlage were to be installed, then its arc suppression and ability to extinguish the arc would be impaired and it might not clear the over current safely.

 

[mull982]

The breaker has to be rated at the voltage you are applying it to. They have to interupt phase to phase faults.

I thought there was a section in the code that specified this? Does anyone recall what it is?

Does anyone recall anything about L-G system voltages as being a determining factor?

 

[jumper]

I thought there was a section in the code that specified this? Does anyone recall what it is?

Does anyone recall anything about L-G system voltages as being a determining factor?

240.85 I believe.