Correction-GFI & AFI Breakers & Shared Neutrals
Asked Jan 28, 2006, 11:38 AM
I need to submit a correction to some advice I had furnished in the past regarding Ground Fault and Arc Fault circuit breakers being used on shared neutrals. I had in mind the typical single pole 120 volt breakers that will not work if two breakers are used for two 120 volt circuits that share a neutral. This advice still stands as true.
However, there does exists 2 pole GFI and AFI circuit breakers that will work to protect two 120 volt circuits that share a neutral. Most of the major circuit breaker manufacturers offer these 2 pole breakers, such as General Electric in the THQL frame, Square D as the QO frame, and Siemens in the QF frame.
These 2 pole circuit breakers did come to mind due to a couple of issues that cause them to be impractical.
One reason is the cost of one of these breakers, in the range of $200-$300 each, and this is wholesale cost. The big box hardware stores may sell these, not sure what the retail cost is.
Another reason is that if there is a fault on one circuit, since the 2 poles of the breaker are physically connected internally, both circuits will be interrupted.
I see there is another request in the Electrical forum pleading to use AFI breakers on a shared neutral. Even thou I believe using 2 pole GFI and AFI breakers as being impractical, it did occur to me that I need to be as accurate as possible, and offer these as a solution, and let the person that will be living with and paying for these breakers be the judge whether to use them or not.
I apologize for any inconveinence my inaccurate or incomplete advice previously submitted may have caused to anyone that may have be misled by not being informed of the 2 pole GFI and AFI circuit breakers that are available.
Last edited by tkrussell; Jan 28, 2006 at 11:57 AM.