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Can you put a GFCI into a circuit with an existing GFCI and what will happen if the two GFCIs are in a series circuit?
Note: The latest types of Ground Fault Circuit Interruptor (GFCI) are also called Residual Current Devices (RCDs).
"Can you put a GFCI into a circuit with a GFCI?" is probably the same question as "What if two GFCI are in series in a circuit?" and the answer is that one GFCI will most likely trip earlier than the other to break the circuit. Which one will trip first depends on the actual difference in sensitivity between the two GFCIs. Leakage currents are measured in mA (1 mA = 1 thousandth of an Ampere) and GFCIs are designed to trip at a certain leakage current with a tolerance of say + or - 3%. So if the basic trip current was 20 milliamps one GFCI might trip at 19.4 mA and the other at 20.6 mA and they would both be within the design specification. The one that trips at 19.4 mA would be expected to trip first. <><><> This question requires answering by a VERY knowledgeable electrician, or an electrical engineer. I am neither, but until the right answer comes along, I will attempt to provide some information which hopefully will allow a better understanding of the issues involved. A GFCI [ground fault circuit interrupter] is much different from, although similar to, a circuit breaker. The DIFFERENCE is WHAT they are designed to detect and react to. The purpose of a fuse or circuit breaker is to detect excess or MASSIVE current flow [ie. a SHORT CIRCUIT, a direct short to ground], and then very quickly turn off the electrical current to the circuit, in order TO PREVENT a FIRE. This is the only thing the breaker is designed and intended to do. This limited capability will not prevent a person from being electrocuted when a fault occurs within an electrical device, if the current flow happens to be low. Voltage and current faults which can kill a person usually will not be detected by a circuit breaker. A ground fault circuit interrupter [GFCI], on the other hand, is designed to, and will, detect those low level currents which can kill a person, BUT which are not great enough to trip a breaker. When a GFCI detects potentially dangerous current it, like a breaker, trips in order to open the circuit. Now as to WHY, when you placed two GFCIs in series [one in the breaker panel feeding one in an electrical receptacle], the first GFCI tripped when the second GFCI is "tested." When you press the TEST BUTTON on a GFCI it puts a high resistance load on the circuit, which simulates a "small" ground fault, and I think both GFCIs "see" the same fault and react as designed and intended. Again, a true professional should "bless" my comments, but I think that there is no danger or hazard in placing two GFCIs in series. On the contrary, I think there is redundant capability in the pairing, with the first GFCI functioning with, and as a backup to, the second. I suggest you contact your local electrial inspection department regarding what the code(s) say about this issue, and also call the tech support people at the 800 number on the packaging for the GFCIs. Another source of information is a local electrical engineer, if you know someone who can help you make contact. Until a more informed answer comes along, I hope this helps you to understand the issues involved. <><><>
As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.
Before you do any work yourself,
on electrical circuits, equipment or appliances,
always use a test meter to ensure the circuit is, in fact, de-energized.
IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.
What else can I help you with?
Why do gfcis trip?
GFCIs can trip due to a ground fault, which occurs when electricity leaks from the circuit. This can happen if water or moisture gets into outlets, there is a wiring issue, or there is a fault in an appliance. Tripping is a safety feature that cuts off electricity to prevent electric shocks and fires.
Do you need GFCI protection in kitchen?
Yes, it is recommended to have Ground Fault Circuit Interrupter (GFCI) protection in a kitchen. GFCIs help prevent electric shock by quickly shutting off power in the event of a ground fault or short circuit. They are typically required for outlets near sinks, countertops, and areas prone to moisture.
What safety devices that stop the flow of electric currents?
Safety devices that stop the flow of electric currents include circuit breakers, which automatically cut off power when overcurrents occur, and ground fault circuit interrupters (GFCIs), which detect imbalances in current flow and shut off power to prevent electric shocks. Additionally, fuses are devices designed to disrupt the flow of electricity in the event of excessive current.
How do you wire a 120 volt gfci into a 240 volt three wire?
You can't. The 120 volt GFCI is probably just a 2-wire (hot, neutral and ground) You would have to run a new 3-wire (2 hots, neutral and ground). The two hots are how you get the 240 volts (120+120=240). Also you must make sure the wire is gauged properly. #10 wire for 30 amps, #12 wire for 20 amps, etc.
How many gfci outlets can you have on one circuit?
You can have multiple GFCI outlets on one circuit; it is common to have them daisy-chained in a series. However, it is recommended to consult with a licensed electrician to ensure proper wiring and compliance with local electrical codes.
Why do gfcis trip?
GFCIs can trip due to a ground fault, which occurs when electricity leaks from the circuit. This can happen if water or moisture gets into outlets, there is a wiring issue, or there is a fault in an appliance. Tripping is a safety feature that cuts off electricity to prevent electric shocks and fires.
Do GFI's go bad over time?
Yes, Ground Fault Circuit Interrupters (GFCIs) can go bad over time due to wear and tear, exposure to moisture, or electrical surges. It is recommended to test GFCIs regularly and replace them if they are not functioning properly.
What are the different types of Square D breaker types available for residential electrical systems?
The different types of Square D breaker types available for residential electrical systems include standard circuit breakers, ground fault circuit interrupters (GFCIs), arc fault circuit interrupters (AFCIs), dual function circuit breakers, and combination arc fault circuit interrupters (CAFCIs).
What are the different types of breakers used in a breaker box?
The different types of breakers used in a breaker box include circuit breakers, ground fault circuit interrupters (GFCIs), and arc fault circuit interrupters (AFCIs). Each type serves a specific purpose in protecting the electrical system and preventing hazards like electrical fires and shocks.
What devices are used to protect people from an electric current?
Electrical devices such as circuit breakers, fuses, and ground fault circuit interrupters (GFCIs) are commonly used to protect people from electric currents. Additionally, electrical insulation, such as rubber gloves and mats, can prevent electric shocks in specific situations.
Do you need GFCI protection in kitchen?
Yes, it is recommended to have Ground Fault Circuit Interrupter (GFCI) protection in a kitchen. GFCIs help prevent electric shock by quickly shutting off power in the event of a ground fault or short circuit. They are typically required for outlets near sinks, countertops, and areas prone to moisture.
How can I upgrade my circuit breaker to improve the safety and efficiency of my electrical system?
To upgrade your circuit breaker for improved safety and efficiency, consult a licensed electrician to assess your current system and recommend appropriate upgrades. This may involve installing a higher amperage breaker, adding ground fault circuit interrupters (GFCIs) or arc fault circuit interrupters (AFCIs), and ensuring proper wiring and insulation. Regular maintenance and inspections are also crucial to ensure the continued safety and efficiency of your electrical system.
What safety devices that stop the flow of electric currents?
Safety devices that stop the flow of electric currents include circuit breakers, which automatically cut off power when overcurrents occur, and ground fault circuit interrupters (GFCIs), which detect imbalances in current flow and shut off power to prevent electric shocks. Additionally, fuses are devices designed to disrupt the flow of electricity in the event of excessive current.
How do you wire a 120 volt gfci into a 240 volt three wire?
You can't. The 120 volt GFCI is probably just a 2-wire (hot, neutral and ground) You would have to run a new 3-wire (2 hots, neutral and ground). The two hots are how you get the 240 volts (120+120=240). Also you must make sure the wire is gauged properly. #10 wire for 30 amps, #12 wire for 20 amps, etc.
How can one bypass a GFCI on a generator?
It is not safe or recommended to bypass a Ground Fault Circuit Interrupter (GFCI) on a generator. GFCIs are designed to protect against electrical hazards and should not be tampered with. It is important to follow proper safety protocols and use the generator as intended to prevent accidents and injuries.
How many gfci outlets can you have on one circuit?
You can have multiple GFCI outlets on one circuit; it is common to have them daisy-chained in a series. However, it is recommended to consult with a licensed electrician to ensure proper wiring and compliance with local electrical codes.
GFCI circuitry checks for what?
Current Imbalance: GFCIs continuously monitor the current flowing in the "hot" (live) wire and compare it to the current returning in the "neutral" wire. If there is a difference of as little as 4-6 milliamperes (mA) between these currents, indicating that some current is not returning through the normal circuit path, the GFCI will trip and disconnect the power. Leakage to Ground: GFCIs are designed to detect any unintended flow of electricity to ground, which could be potentially hazardous. This can occur when there's a fault in an electrical device, damaged wiring, or when someone comes into contact with a live wire or conducts electricity to the ground. Rapid Response: GFCIs are engineered to respond quickly, typically tripping within milliseconds when they detect a ground fault. This rapid response helps prevent electric shocks and electrical fires.
