zog
Senior Member
- Location
- Charlotte, NC
You don't need 1000A on GF, it is likely a much lower pick up setting, 200A or so. Is this a 3 or 4 wire system? That makes a big difference in how GF's are sensed by the trip unit.
main breaker tripping
- Thread starter malachi constant
- Start date
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You don't need 1000A on GF, it is likely a much lower pick up setting, 200A or so. Is this a 3 or 4 wire system? That makes a big difference in how GF's are sensed by the trip unit.
This reminds me the time my warranty department manager called me to visit a warehouse grocery store where a panel board OEM had built and installed a panel with one of our 1200a 480v breakers with GF as a main. Their complaint was that the breaker was nuisance tripping randomly shutting down the entire store. The store was located in my territory and even though I was in field sales I agreed to make a site visit only the sales rep for the OEM came with me.
I took my electronic test kit me and tested the breaker which tested out perfect. I had also brought along a replacement circuit board that the warranty manager already shipped to me via FedEx. The problem persisted.
Then!!! The terminal block tucked on the side of the of the breaker just happened to catch my eye where other were 4 terminals, 2 for the neutral CT and 2 for a remote indicator. The neutral CT was terminated on the wrong terminals and the breaker was not seeing the neutral current and was reading any neutral current as a ground fault.
I pointed that out to the panel builder's salesman that it was their wording error that caused the problem handed him the screwdriver and told him to fix it. I'll
I took my electronic test kit me and tested the breaker which tested out perfect. I had also brought along a replacement circuit board that the warranty manager already shipped to me via FedEx. The problem persisted.
Then!!! The terminal block tucked on the side of the of the breaker just happened to catch my eye where other were 4 terminals, 2 for the neutral CT and 2 for a remote indicator. The neutral CT was terminated on the wrong terminals and the breaker was not seeing the neutral current and was reading any neutral current as a ground fault.
I pointed that out to the panel builder's salesman that it was their wording error that caused the problem handed him the screwdriver and told him to fix it. I'll
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
My guess is the breaker 'injection testing' was nothing more than a secondary test set. I am also pretty confident a GF system test was not performed, at installation, per the NEC.
Schedule an outage, have a qualified testing company (not your present electrician, although they can help) come in and do a complete commissioning of the GF system, including a primary injection test. This should take less than 4 hours and involve lifting the neutral-ground bonding jumper as well as meggering the neutral to ground busses.
Schedule an outage, have a qualified testing company (not your present electrician, although they can help) come in and do a complete commissioning of the GF system, including a primary injection test. This should take less than 4 hours and involve lifting the neutral-ground bonding jumper as well as meggering the neutral to ground busses.
zog
Senior Member
- Location
- Charlotte, NC
^^^^^ yep 
- Status