Transformer Overcurrent Protection 450.3 C)

[human7]

450.3 (C) Over Current Protection states "Voltage transformers installed indoors or enclosed shall be protected with primary fuses."

Would I be correct to assume the term "Voltage Transformer" is used to refer to instrumentation voltage transformers exclusively? Power transformers installed indoors can be protected by circuit breakers can't they?

 

[raider1]

I agree, power transformers such as a 50 Kva 480 to 280/120 volt Wye transformers can be protected on the primary by a circuit breaker.

Chris

 

[lakee911]

450.3 (C) Over Current Protection states "Voltage transformers installed indoors or enclosed shall be protected with primary fuses."

Would I be correct to assume the term "Voltage Transformer" is used to refer to instrumentation voltage transformers exclusively?

CBs can be used, but I don't know exactly what a voltage transformer is and how it differs from a standard 'transformer.' Odd.

 

[steve66]

See the fine print note that refers to 408.52 which talks about instrument circuits, and fuses rated 15 amps and less.

Steve

 

[templdl]

Voltage transformers sometimes refered to as a VT or more commonly refered to as a PT for potentional transformer are used with voltmeters, watt/watt hour meters and for relaying.
Potential Transformer is designed for monitoring single-phase and three-phase power line voltages in power metering applications. The primary terminals can be connected either in line-to-line or in line-to-neutral configuration. Fused transformer models are designated by a suffix of "F" for one fuse or "FF" for two fuses. A Potential Transformer is a special type of transformer that allows meters to take readings from electrical service connections with higher voltage (potential) than the meter is normally capable of handling without at potential transformer.

 

[human7]

Thanks guys.