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Questions tagged [gfci]

For questions about ground fault circuit interrupters (GFCIs), which are safety devices that break a circuit when they detect a leakage current to ground. Consider using in conjunction with related tags such as "safety", "protection", etc., if applicable.

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Ground Fault Interrupter

I was trying to simulate a circuit where it can detect grounded neutral conditions in the household. I need to have a current transformer which can detect the current differential ans sends a signal ...
M S's user avatar
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4 votes
2 answers
366 views

Two X capacitors from lines to ground- why? GFCI fault, even after replacement

I'm trying to repair a very old printer (circa 1980). When I plugged it in, the GFCI outlet protection immediately tripped, even with the printer turned off. The hot side of the cord is connected to ...
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0 answers
56 views

Motor tripping GFCI

I have a 1HP 3-phase motor hooked up to a variable speed controller and phase converter which uses standard 120V household current. However, when the motor is turned on it invariably trips the GFCI ...
Tyler Durden's user avatar
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2 votes
0 answers
189 views

Can I put ferrite cores around the romex in my electrical boxes and breaker panel? [closed]

I've recently replaced most of the breakers in my house with dual-function arc fault/ground fault protection. (I spent five years in forensics, I'm deeply paranoid, don't judge me.) Naturally I'm ...
Stephen Collings's user avatar
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0 answers
47 views

The output negative pole (-) of my PSU is connected to protective earth. Why doesn't it trigger the GFCI?

I am living in Europe and the power plug (Schuko plug) of my PC PSU has 3 pins. These pins are the positive pole (+), the negative pole (-) and protective earth (PE pin). Please let me say in a few ...
zomega's user avatar
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0 votes
1 answer
125 views

Working of this circuit - GFCI circuit

Above is a snippet taken from a TI app note from here. It a GFCI circuit. There are saying to connect a CT. Can someone tell me the working in a little more detail and the flow of current and voltage ...
Freshman's user avatar
0 votes
3 answers
74 views

Will this scenario trip the GFCI?

An inline GFCI rated at 15A 120VAC with 4-6mA trip level is used to provide 120VAC to an AC-DC converter. The converter outputs +12VDC with max 1A current. This is then used to power a high voltage DC-...
earl's user avatar
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2 votes
3 answers
467 views

Do I still need a fuse if I'm using a GFCI?

RE: PD involving a small health & beauty product similar to a foot spa whereby the user will come into contact with water. General description: Because malfunctioning foot spas have been known to ...
tayglo's user avatar
  • 95
1 vote
2 answers
51 views

Static dissipation mat tripping AGFCI breaker

I have a home lab that I try to keep some level of static protection on, so I have a cheap anti-static mat that is grounded to a normal outlet in my lab. I recently installed a AGFCI circuit protector ...
Sam's user avatar
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-1 votes
1 answer
86 views

Please explain the interaction I observed between a GFCI receptacle and a 3000 volt arc

The high voltage leads of a 120 to 3000 volt transformer, current limited to 30 mA, were each wrapped around a small nail. The nails were allowed to rest upon a piece of wood soaked in an electrolyte. ...
solenoids are cool's user avatar
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1 answer
469 views

GFCI tripping when using hair trimmer, but only when using an extension cord

I have a GFCI socket in a recently-build bathroom. My hair trimmer trips it often when stopping under some conditions and while I have a fix I'd like to better understand what exactly is going on here....
Thomas Guyot-Sionnest's user avatar
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1 answer
111 views

Should I expect the heating element in new cartridge heaters to be electrically isolated from the stainless steel exterior sheath?

I have two five-year-old 16 mm x 428 mm, 115 VAC, 1000 W cartridge heaters that have approximately 200 kΩ from the heater leads to the exterior stainless steel sheath. Is this normal or should I ...
ajschauer's user avatar
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0 answers
49 views

What are the implied peak current ratings of GFCI's?

Using GFCIs with transformer or other high-inrush current loads is problematic, because in some designs the differential transformer core can locally saturate and produce an invalid output in the ...
Kuba hasn't forgotten Monica's user avatar
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1 answer
85 views

What will happen if I press the GFCI button on an electrical tester when it is connected to a regular socket? [closed]

I know that the GFCI button on the tester engages the safety mechanism on the GFCI protected wall outlet. My question is: suppose I have a regular wall outlet, which is not GFCI protected, and is only ...
Ahmad-San's user avatar
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0 answers
62 views

Sensing Ground Faults on a High Voltage Pulser - Coupled Inductor Issue in LTSpice

I am building a ground-fault protected High Voltage Pulser. The pulses may be as high as 500V and as narrow as 50us (20kHz). The question of how to create GFCI protection is proving to be a ...
banjoeschmoe's user avatar
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0 answers
247 views

Off-Grid Inverter causing a GFCI trip when charging EV

I have a transformer-less, 48VDC to 120/240VAC inverter that is off-grid. I have a 120VAC GFCI outlet wired to the inverter. When I plug my 120VAC EV charger into the outlet, the GFCI trips. It does ...
Lost Puppy's user avatar
2 votes
1 answer
125 views

How does a RCBO trip from a vapourised PCB trace?

I was replacing a power board with a new (plastic insulated) one, which resulted in a trip of the 20A 30mA RCBO on the circuit instantly upon turning on one of the board outlets. The built-in 10A ...
小太郎's user avatar
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3 votes
5 answers
3k views

Minimum current level to trip a GFCI

TLDR I originally asked "Minimum current level to trip a GFCI"? But the answers pointed out that my biggest problem in this question is that I shouldn't use a general-purpose DMM to find an ...
Mike Pennington's user avatar
1 vote
1 answer
311 views

How can I prevent my multi-meter fuse from blowing with a brief 120VAC surge?

I wanted to test how much power a GFCI outlet uses while idle, so I hooked up my multi-meter to test the current flow. I put my test lead in the amp socket, and confirmed the current was on the order ...
Steve Sether's user avatar
1 vote
5 answers
951 views

120v Inverter and GFCI

I have a 48vdc to 120vac inverter with a 3 wire output (hot, neutral and ground). I installed a GFCI outlet using those output wires. I tried putting a resistor (I tested with 1k 100 and 22 ohm values)...
Daniel Caoili's user avatar
1 vote
2 answers
244 views

Selecting residual current for RCBO

I'm creating a portable test socket for electrical appliances that comes equip with a RCBO, power meter and possibly emergency stop button. My test socket will operate at max 240V AC and 10A. The ...
Max's user avatar
  • 547
0 votes
1 answer
235 views

Sanity check for current transformer burden resistor calculations

I'm hoping to use this(CR8420-1000-G) current transformer to detect ground faults of 20mA. Using the formulae in the datasheet: Here are my calculations: They say For best linearity, choose R ...
Matthew Goulart's user avatar
1 vote
1 answer
218 views

Does this circcuit pose a safety risk that could be avoided?

I was looking over the circuit design for OpenEVSE. I was specifically interested in the GFCI portion of the circuit: This circuit measures the current difference between Line and Neutral on a 120/...
Matthew Goulart's user avatar
1 vote
1 answer
170 views

Safety precautions when developing and testing mains voltage devices [closed]

Specifically, I am planning to design and build an energy meter to measure power drawn from mains - 120V 60Hz. What are the risks associated with developing and testing this device and how to minimize/...
Fiebbo's user avatar
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1 vote
0 answers
59 views

Extension cord from grid through GFCI outlet to off grid inverter. Does the extension cord ground need connected?

I have an off grid system: PV, charge controllers, inverters, and batteries. I want to add a 120V grid input from a GFCI outlet through an extension cord directly into the inverter AC input. However, ...
Lost Puppy's user avatar
0 votes
1 answer
96 views

Can a grounded thermocouple cause GFCI to trip?

I noticed the tip of my soldering iron is case grounded. I understand the GFCI compares voltages and trips if there is a difference (in the millivolt range). If the thermocouple generates a small ...
user148298's user avatar
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2 votes
2 answers
2k views

Automatic Self-Test Circuit in GFCI outlet

What kind of self-test circuits or method do they used in the GFCI outlets generally? Is it just firmware or is there a physical addition (and what it is usually?) This is because after 2015, it is ...
Samzun's user avatar
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