erickench
Senior Member
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- Brooklyn, NY
Hi Guys, I just need a clarification on the above NEC section. When they speak of ground fault protection do they mean the Phase Overcurrent ANSI #50/51 relays or is it something else?
NEC 230.95
- Thread starter erickench
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ron
Senior Member
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- New York, 40.7514,-73.9925
It is not.
If it is medium or high voltage, they mean relay protection with a N or G in the ANSI number.
If it is medium or high voltage, they mean relay protection with a N or G in the ANSI number.
230.95 does not specify the type of GFP to be utilized but rather stipulates the performance characteristics of the system that is (to be) employed.
erickench
Senior Member
- Location
- Brooklyn, NY
erickench
Senior Member
- Location
- Brooklyn, NY
Okay, N and G mean neutral and ground respectively. I'm designing a 1000A service at 208/120 volts. I'm trying to come up with GFP scheme as per code requirements. I saw in the Square D catalog a device designated as GROUND-CENSOR 100-600 VAC. The catalog had a little diagram showing a square shaped CT(sensor) connected to the device itself. The device controlled a circuit interruptor. Unless I'm mistaken the sensor looks to be downstream and the circuit interruptor to be upstream. But the IEEE Buff book show's it in reverse. Can anyone help me with this?
- Location
- Illinois
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- retired electrician
The code does not require ground fault protection for that system.
erickench
Senior Member
- Location
- Brooklyn, NY
Okay, thanks.
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
Eric,
It is less than 150V to ground, so you are okay without it.
If it was 480/277V or larger (I thought the ANSI references meant you were used to working on medium or high voltage, since we don't use those terms in low voltage), you just buy the main breaker with GFP. No need to buy specialized accessory systems as it makes it more complicated, unless it is a fused switch with shunt trip, then you need the extra system.
It is less than 150V to ground, so you are okay without it.
If it was 480/277V or larger (I thought the ANSI references meant you were used to working on medium or high voltage, since we don't use those terms in low voltage), you just buy the main breaker with GFP. No need to buy specialized accessory systems as it makes it more complicated, unless it is a fused switch with shunt trip, then you need the extra system.
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