John Chue
04-03-2014, 12:39 AM
Hi,
I've been reading a lot about grounding, bonding, GFI,GFCI and AFCI that need clarification.
I worked for Underwriters Laboratories as a Lead, writing standards and performing field evaluations. I have worked as a reliability and safety engineer in both aircraft and space applications.
I just want clarify some important things.
1. GFCI and GFI's are not the same. GFI's, AFCI's and CB's are for preventing overload and protect against fires. GFCI's are to protect people from shock.
2. Grounding is for protection and bonding is for conducting between surfaces or conductors.
3. Neutral is for return path and per NEC bonded to Ground at the Mains. This is to prevent a floating voltage that can exist between Neutral and Ground, leading to a shock hazard or equipment functional problems down stream. Also note, Mains does not mean "Main Circuit Panel". NEC refers to Mains as the disconnect switch....which may be in located in the Main circuit panel "if wired that way" or it may be located in a separate panel from the Main Circuit Panel(where all circuit breakers are installed). So it is important to understand that many panels are improperly grounded at the wrong location.
I've been reading a lot about grounding, bonding, GFI,GFCI and AFCI that need clarification.
I worked for Underwriters Laboratories as a Lead, writing standards and performing field evaluations. I have worked as a reliability and safety engineer in both aircraft and space applications.
I just want clarify some important things.
1. GFCI and GFI's are not the same. GFI's, AFCI's and CB's are for preventing overload and protect against fires. GFCI's are to protect people from shock.
2. Grounding is for protection and bonding is for conducting between surfaces or conductors.
3. Neutral is for return path and per NEC bonded to Ground at the Mains. This is to prevent a floating voltage that can exist between Neutral and Ground, leading to a shock hazard or equipment functional problems down stream. Also note, Mains does not mean "Main Circuit Panel". NEC refers to Mains as the disconnect switch....which may be in located in the Main circuit panel "if wired that way" or it may be located in a separate panel from the Main Circuit Panel(where all circuit breakers are installed). So it is important to understand that many panels are improperly grounded at the wrong location.