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GFCI Breaker Question
New kitchen in a school. Several 120V 20 amp circuits protected by gfci breakers. Is it almost a forgone conclusion that these breakers will trip during power outage? Or could it be a bad brand of breakers? If so, we lose all product in the reach in coolers if that happens when we aren’t there. That’s what head electrician over the job told me. During spring break, almost all those breakers tripped. Getting the electrical engineer over the job involved at some point.
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10 Replies
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That’s not true. GFCI breakers can be spec’d with different milliamp trip values. Generally they are 5 ma for home use. But commercial HVAC breakers can be bought 8, 10 15 and 20 ma. It takes 10 milliamps for a human to even feel electricity. 25 for pain and a inability to let go. 30 to cause cardiac arrest.
Now that you have multiple breakers dropping out after a power surge, that’s a problem. probably beyond GFCI. It could be your power regulator (on the pole) overshot the design voltage for your building. Or you have a long run from your breaker panel to the coolers. Or the breakers were wired wrong in the panel. There should be a ground terminal bar and a neutral terminal bar. The GFCI white goes to the neutral bar and the ground wires (Green) go to the ground bar. The GFCI senses that the power current and the neutral current are equal. A flow loss is what trips the device. Equipment that has larger capacitors can cause false trips as the capacitor charges. Long runs or runs close to other power wiring can cause induced power.
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I told the guy I wasn’t buying it and wanted further inspection. I will stipulate that he was not in charge of this part of the job when it was done, he took the place of someone else But still… When we took over, had a 20 amp outlet circuit that was tripping breaker immediately. Instead of finding the problem, he replaced with a regular breaker When the job calls for gfci breaker I told him they will have to go through the whole thing and fix any problems I do not want to inherit problems when the responsibility turns over to us Thank you!
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Each cooler/freezer requires its own branch circuit. If these are reach in units of between 17 and 50 cubic feet, there has to be a circuit for each one. And as of 2020, they may require AFCI breakers. Depending on the building spec. If they tandem the coolers on breakers, the start the loads all at once would trip them. A cooler has 17 times full run current at start. If your power is off long enough for all thermostats to call for cooling, Thats a considerable inrush. Your supply panel should have a breaker for each cooler. Also check that the breakers have a HVAC rating on the face. They take a bit more time to trip than a standard one.
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Each of the breakers has a single outlet on the circuit. The coolers pull either 15 or 16 amps. I will check the specs on the breakers. If memory serves, I believe they are GFCI breakers, not AFCI. Not sure exactly when this job started. Probably 2020. Head electrician currently over the rest of the project told me I would wind up changing the breakers to regular style. I told him can’t do that since GFCI are required. Not taking a chance on something happening and get in trouble over that.
When we took over the kitchen, had a gfci breaker tripping immediate;y with no load plugged into outlet. He replaced the required gfci breaker with a regular one. And he had said gfci was required! So that’s why I’ve got to get someone else higher up involved. Thanks!
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Has this space set unheated over a extended time with moisture like rain or fog? If so that may cause the tripping to happen till all the wiring dry’s out. But still, the GFCI spec should have been a commercial spec or industrial spec. Residentials trip at 4 to6 milliamps. Industrial can be as high as 40ma. Check what was spec’d. They may have used under spec’d breakers.Big cost difference.
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They finished this kitchen roughly two years ago. It’s been heated and cooled as should be. Kitchen has just been turned over to us because they just completed the dining hall. They finished construction on the kitchen before they started construction of the dining hall! Sorry, but this construction job has been a thorn in our sides for awhile now. Now they are saying it may be summer(when kitchen shuts down) before they tackle the problem. And I can live with that since it’s not for off. Architect tells me that the electrician thinks he may know what the problem is. We will see. Thank you for your time and advice!
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Tee, let me know what they find and what they use as a solution. The code changed in 2020 to have a heavy influence on GFCI and AFCI. The 2023 book isn’t out yet, but I’ve heard that they have backed off on some things.
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He looked at the problems a few days ago, but I wasn’t there. I know they found reversed polarity on at least one of the circuits. It appears two of the three circuits are fixed. The third circuit that was tripping with a warmer attached, he claimed the warmer to be bad. I moved warmer to another circuit and had no problem. When I find time, I will amp the warmer out to see what it’s drawing. Not calling it quits yet. Lol Thanks for your help and will let you know what else we find.
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Ohm the L1 and ground terminal on the warmer. It should be infinite. Make sure to try it both off and on. And don’t be afraid to rattle the unit around a little.
As for the miswiring, What the hell kind of electricians are they? That should never happen with a commercial electrical company. Ideal makes a simple plug in GFI tester that is inexpensive, and you should probably get one and test all the outlets in the building before acceptance. It has 3 LED’s that will tell you of any miss wire. If they find one and correct it at the wrong box, it may make ones downstream wrong. It also has a button that adds a high resistance path to ground that should trip any GFI.
The wires are color coded as well as the terminals on the receptacles. Colors like red, black, yellow, blue, violet, and orange are always live. Orange is reserved for the wild leg in Delta systems. Neutral is always white or Gray in the US. Green is always ground in North America. European Machines can have a different color ground. And even colored neutral’s.
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I will do as you have suggested. I did amp the warmer, and there was no problem there. But your test will be a better way. As for the head electrician that was over the job when it was done, I know nothing of him. He was gone when I came on board. His responsiblity though. As for the new guy, as you know, I haven’t been too pleased with couple things he has done. Can’t thank you enough for your help! No gfci problems in the other two new kitchens that were built here, but different contractors as they were all built at the same time.
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