bimmer528,
A GFCI breaker cannot be used on multi wire branch circuits. ( The neutral is shared on multi wire branch circuits) The GFCI breaker will just trip open the second any load is connected to the other hot circuit wire of the multi wire branch circuit.
The hot and neutral connected load to the GFCI must be balanced. If an imbalance is detected on either line the breaker will trip open.
In the case of a 120V circuit where a GFCI breaker is used each 120V circuit has to have its’ own neutral conductor. Both the Hot, ungrounded conductor, and the neutral, the grounded conductor, of the branch circuit connects to the single pole GFCI breaker. (Depending on the electrical panel, the GFCI breaker used may have an insulated white neutral pigtail wire that connects to the neutral bus in the panel, or the breaker may be the type that connects directly to special neutral bar, rail.)
I personally prefer using a GFCI duplex receptacle over a GFCI breaker.
In the case of a multi wire branch circuit where GFCI protection is needed, or required per code, example in a kitchen above counter tops, A GFCI duplex receptacle is used.
In my previous post I asked you about if Chicago requires AFCI (Arc Fault Circuit Interrupter) protection in dwelling units.
2014 NEC requires the use of CAFI (Combination Arc Fault Interrupters) on all 120V 15 amp and 20 amp lighting and receptacle outlet branch circuits in dwelling units for new construction, as well as a newly installed branch circuit/s in existing dwelling units.
The CAFI device can be a CAFI breaker or a CAFI duplex receptacle device. The CAFI will trip open, breaking the circuit, if it detects series or parallel arcing.
A GFCI’s purpose, function, is to protect life from electrocution. If the sensing unit in the device detects more than 5 to 6 ma of ground fault current from the hot to an earth grounded object the unit will trip open. (The earth grounded object could be the safety equipment grounding conductor, or any other earth grounded object the person, or pet, may come into contact with while in contact at the same time with the HOT conductor.)
(NOTE: The actual ground fault circuit is from the HOT conductor >> through the person’s body >> out to the earth grounded contacted object >> to the electrical service’s earth grounded service neutral conductor. A complete closed circuit.)
A CAFI’s purpose, function, first priority is to protect property from an electrical fire caused from an electrical arcing event. By doing so ultimately the CAFI may protect life if a person or pet is in the home at the time of the electrical arcing event.
Like the GFCI breaker a CAFI breaker cannot be used on a multi wire branch circuit. Like the GFCI breaker both the Hot and neutral conductors of the branch circuit connects directly to the breaker.
Has there been problems with AFCI/CAFI breakers nuisance tripping? yes... Not so much now though. Most of the problems were because of improper installation of the branch circuit wiring and improper connections in electrical outlet boxes.
Some problems with nuisance tripping with the early AFCI breakers was because of interactions with some lighting dimmers. Lutron being one such dimmer.
As always, the AHJ has the final say...
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