What happens if the shared neutral returns to the GFCI?
If the shared neutral returns to the neutral bar, no neutral current would be seen by the GFCI breaker. If the neutral returned to the GFCI, it would see ALL of the current from both circuits. Either one would obviously not work. Hope this helped. I think those explanations help me out.
Can a GFCI outlet be fed from a shared line side?
That is why receptacles can be fed from circuits with shared line side neutrals. But if you think about it, a circuit breaker is always fed from a source that also has shared line side neutrals. So the problem is always with the load side of the GFCI.
Do GFCI circuit breakers have a separate terminal for neutral?
GFCI circuit breakers have a separate terminal for the neutral wire which must be run with the hot wire. Actually it is as simple as "what goes out must come back" and "if it didn't go out it can't come back". GFCIs only look downstream, they don't really care what they are connected to.
What causes a false trip on GFCI?
"False" trips will occur if there are any shared load side neutrals between "hot" conductors that do not start at the same GFCI device whether it is a breaker or a receptacle. I am a little unclear of why it is acceptable to share a neutral between a circuit that has GFCI receptacles on the load and a circuit that has normal receptacles.
What is a GFCI sensor?
Do you need to keep neutrals separate on a GFCI?
Can GFI breaker share a neutral?
Can a 2-pole CAFI, GFI or EPD breaker be used on (2) 120 V circuits with a shared neutral? Resolution: Yes, 2 pole CAFI, GFI, and EPD circuit breakers can be used to feed two single pole 120 Vac circuits with a common neutral. This situation often occurs when a multi-wire conductor is used to feed the 2 circuits.
Can you share a neutral for two circuits?
This is also known as a common neutral, and the circuits and neutral together are sometimes referred to as an Edison circuit. In a 3-phase system it is legal in some jurisdictions to share a single neutral wire between all three (3) phases. One neutral may not have two “hot” wires from the same phase.
Will a neutral ground trip a GFCI?
To meet this requirement, GFCIs trip when the load side neutral and equipment grounding conductors are joined, even if there is no ground fault. Test circuit.
How many branch circuits can share a neutral?
As you also mention, neutral conductors are not allowed for more than one branch circuit or one multiwire branch circuit or one set of ungrounded feeder conductors as stated in 200.4(A), unless specifically permitted elsewhere in this Code.
What does sharing a neutral mean?
A shared neutral, in electrical circuits, is a common connection for the neutral lines that usually carry a near zero net current. In the case of a three-phase circuit, the neutral line current for a balanced three-phase load is zero or very minimal.
Why does a GFCI trip when neutral touches ground wire?
GFCI devices work by comparing the current incoming on the hot wire to the current leaving on the neutral wire. If there's a difference, it means electricity is leaving the circuit somehow (a "ground fault") and the GFCI cuts power*.
Does GFCI break hot or neutral?
GFCIs (of all types) are required to break hot and neutral, unlike regular fuses, switches, or breakers. This is not spelled out in UL 943, but is implied by the requirement in UL 943 6.7.
What causes a GFCI to trip with nothing plugged in?
What could be causing it ? Typically there are other outlets on the same circuit with the GFCI outlet. The problem device could be plugged into one of those other receptacles. Typically there are other outlets on the same circuit with the GFCI outlet.
Can dedicated circuits share a neutral?
A dedicated vs separate circuit is the argument-- As I seeit a dedicated circuit should not share a neutral and a separate circuit may share it.
Can multiple switches use the same neutral wire?
If both switches are powered by the same breaker you can wire both to the same neutral.
Can you share a neutral in residential?
The short answer to your question is that, for a residential house, sharing a neutral between two circuits is: Allowed in a Multi-Wire-Branch-Circuit (MWBC) as shown below.
Can two circuits share one ground?
The code requires each branch circuit to have an equipment ground (either a wire, or conduit, or cable tray as in 250.120A), they can be shared when they are in the same raceway. If all the 20A circuits are in one raceway then you just need one ground.
What is a GFCI sensor?
The GFCI has a sensor that compares the current hot the hot terminal against that on the neutral. If they differ by 5 ma it trips. Thus the neutral on any down stream load has to be connected to the neutral on the GFCI load terminal and ONLY to that load terminal. If it connects any place else either the return current can be shunted off or you can get return current from a source other than that GFCI hot terminal.
Do you need to keep neutrals separate on a GFCI?
Once you start connecting on the LOAD side of a GFCI you need to keep the neutrals separate.
Why can't you share a grounded conductor?
Because gfcis see a difference in current going out verses returning. Unless all phases and grounded conductors go through the same Ct you cannot share the grounded conductor.
Can nuetrals be shared?
They will not work properly sharing nuetrals.
Did they cover MWBC?
Not really, they probably covered MWBC but never went deep into the science behind the concept.
Do you need a separate neutral for a GFCI breaker?
Need to run separate neutral for each. If you had a 2 pole GFCI breaker, those two hots would share one neutral.
What happens if an ungrounded conductor is extended through a GFCI receptacle?
If an ungrounded conductor is extended through a GFCI receptacle, then the corresponding neutral must also extend through the sensing coil of that GFCI.
What is a GFCI breaker?
The GFCI breaker is attached to one hot and the shared neutral of the panel. The protected branch circuit from the GFCI breaker is a hot an a neutral. To work and have the GFCI protection, the LOAD side wiring of the GFCI breaker has to not by crossed over to other hots or other neutrals.
How many hots are in a GFCI breaker?
Think of a GFCI breaker connected at a panel. The bus and the neutral of the panel are "like" a multiwire branch circuit in that there are two hots and a shared neutral.
What do you need to do when you have a neutral?
Another thing you need to do is use a double pole breaker or tie 2 breakers together that are sharing the neutral. Both circuits must turn off together when sharing a neutral.
Does a GFCI receptacle work if it is a hot neutral?
In the situation you ask about in your opening post, everything works if the GFCI receptacle LINE is taken from one hot and the multiwire home run neutral, and then the LOAD side wiring of the GFCI receptacle (if there is any) is kept from connection (crossed over) to the hot or neutral of other circuits. Any thing plugged into the receptacle of the GFCI is only a hot an a neutral, so that is not crossed over.
Does the entire current path for a load flow through the circuitry of that GFCI in order to work?
The entire current path for a load must flow though the circuitry of that GFCI in order to work.
Is it safe to separate a neutral?
I think it's a good idea. Especially in panels where neutrals aren't marked with the circuit numbers. Makes working on circuits a lot safer. You might turn a circuit off and think the neutral isn't carrying a load, then go to separate the neutral and it's still carrying the load of another citcuit. Not a safe situation. Especially in commercial and industrial settings.
What is GFCI circuitry?
The GFCI circuitry measures the current on the hot and neutral conductors and compares them. In the absence of any ground faults, the current returning through the neutral is the same as the current going out the hot conductor. If there is a ground fault, then some current is returning through the EGC or through ground.
Is #17 a GFCI?
On the other hand, if #17 is a standard breaker and #19 is a GFCI breaker sharing the same neutral, then the total neutral current is NOT inherently equal to the hot current on only the GFCI circuit and the GFCI cannot function properly.
Can a GFCI receptacle be fed from a shared neutral?
That is why receptacles can be fed from circuits with shared line side neutrals. But if you think about it, a circuit breaker is always fed from a source that also has shared line side neutrals.#N#So the problem is always with the load side of the GFCI. "False" trips will occur if there are any shared load side neutrals between "hot" conductors that do not start at the same GFCI device whether it is a breaker or a receptacle.
Do GFCI receptacles work?
Yes. GFCI receptacles work fine supplied by a multi-wire circuit.
Does a GFCI work with a shared neutral?
Absent any fault, they will always be equal. So this solution works.
What is a GFCI breaker?
Just like a single pole GFCI breaker: hot wires to the designated breaker terminals, neutral to the designated breaker terminal, breaker pigtail to the neutral bar. The GFCI breaker monitors the current balance, any imbalance 5mA or greater trips the breaker.
How to install GFCI recepts?
As long as the GFCI recepts are downstream of the split where each GFCI has its own neutral you will be fine. You run your 12/3 to a junction box and then split so that red/white is on one split and black/white on the other split. Install your GFCI's immediately after the junction box using the "line" screws, and all downstream recepts from there connect to the "load" screws.
Why split a GFCI circuit?
That's why most people just split up the circuits after the initial 12/3 run and use two GFCI receptacles plus downstream regular receptacles, or keep the circuits completely separate on 12/2 runs on GFCI breakers right from the panel. It's much cheaper.
Does a 12/3 GFCI work with a single pole breaker?
btharmy is correct, that the technique you quote " (12/3 to first gfci recep, wirenut one circuit use the other, then in second recept wirenut second circuit and use first, etc)" will NOT work with single-pole GFCI breakers and will NOT work with GFCI receptacles. It's because of the shared neutral through the whole run. It will ONLY work with a double-pole GFCI breaker, because that's the only technique in which the breaker knows about the full activity on both circuits.
Can you use a double pole GFCI breaker?
You can IF you use a double pole GFCI breaker.
Can you use two GFCIs?
"The only way to use two GFCI receptacles to provide GFCI protection to more than two total receptacles on a shared-neutral circuit is to stop sharing the neutral after the GFCIs - by using two seperate 12/2's , or 12/2/2. You can still use 12/3 to feed the first set (the GFCIs), but will need to immediately end the 12/3 after the first GFCI."
Can a GFCI breaker be neutral?
There is only one neutral connection on the breaker. It has to be a double pole GFCI, two singles will not work.
What is a GFCI sensor?
The GFCI has a sensor that compares the current hot the hot terminal against that on the neutral. If they differ by 5 ma it trips. Thus the neutral on any down stream load has to be connected to the neutral on the GFCI load terminal and ONLY to that load terminal. If it connects any place else either the return current can be shunted off or you can get return current from a source other than that GFCI hot terminal.
Do you need to keep neutrals separate on a GFCI?
Once you start connecting on the LOAD side of a GFCI you need to keep the neutrals separate.
