gfci replacement
- Thread starter fireryan
- Start date
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GFI don't protect against lightning under any circumstances. They're not designed for that.
GUNNING
Senior Member
- Location
- Gainesville, Florida
If ya hav to ask .....
Charlie Bob
Senior Member
- Location
- West Tennessee
GFCI receptacles are designed so they responde to a difference of current between ungrounded and grounded conductor ( Hot and Neutral in your 2 wire example)
They are supposed to trip at as little as 5 mA if i remember correctly. That's how it's safe to install them to replace 2 wire recep. They don't require a ground to function properly.
They are supposed to trip at as little as 5 mA if i remember correctly. That's how it's safe to install them to replace 2 wire recep. They don't require a ground to function properly.
Quick answer the GFCI has a coil that senses an inbalance on the load side. If either conductor on the protected circuit deviates between 4 and 6ma from the other the GFCI will trip and open the protected circuit. For example if a person touches the hot conductor and a grounded object on the GFCI protected circuit and creates 4 to 6ma load it will trip. Note the 4 to 6ma is for a class A type GFCI.
A GFCI is a device that measures the amount of current going out on the hot (ungrounded) and compares that with the amount of current coming back on the neutral (grounded). If they are equal, everything's fine.
If there is an imbalance, the GFCI opens the circuit.
The ground wire does nothing on the operation.
If there is an imbalance, the GFCI opens the circuit.
The ground wire does nothing on the operation.
Only if you install grounding receptacles downstream. You will also need to label it as being "GFCI protected".
kwired
Electron manager
- Location
- NE Nebraska
going back to OP about lighting protection even a standard receptacle with a ground connected is not considered lightning protected.
If you plug in a three wire surge protection device into a grounded receptacle you will have a ground reference to which this device can shunt a surge current from one of the other lines.
If you have a grounded receptacle with no ground (GFCI or not) there is no ground reference and no place to shunt to except between the other two lines if the protection unit will even do this, if not the surge will most likely pass on thru the device.
direct lightning hit - all bets are off on any protection device.
If you plug in a three wire surge protection device into a grounded receptacle you will have a ground reference to which this device can shunt a surge current from one of the other lines.
If you have a grounded receptacle with no ground (GFCI or not) there is no ground reference and no place to shunt to except between the other two lines if the protection unit will even do this, if not the surge will most likely pass on thru the device.
direct lightning hit - all bets are off on any protection device.
jwjrw
Senior Member
Yea I once again assumed 3wire receps going on the load side.... In my mind I thought they only needed no equipment ground stickers but im sure you are correct. My customers would pull those stickers off before the glue could stick...
Yea I once again assumed 3wire receps going on the load side.... In my mind I thought they only needed no equipment ground stickers but im sure you are correct. My customers would pull those stickers off before the glue could stick...
For everyone's benefit:
406.3(D)(3) Non?Grounding-Type Receptacles. Where attachment to an equipment grounding conductor does not exist in the receptacle enclosure, the installation shall comply with (D)(3)(a), (D)(3)(b), or (D)(3)(c).
(a) A non?grounding-type receptacle(s) shall be permitted to be replaced with another non?grounding-type receptacle(s).
(b) A non?grounding-type receptacle(s) shall be permitted to be replaced with a ground-fault circuit interrupter-type of receptacle(s). These receptacles shall be marked ?No Equipment Ground.? An equipment grounding conductor shall not be connected from the ground-fault circuit-interrupter-type receptacle to any outlet supplied from the ground-fault circuit-interrupter receptacle.
(c) A non?grounding-type receptacle(s) shall be permitted to be replaced with a grounding-type receptacle(s) where supplied through a ground-fault circuit interrupter. Grounding-type receptacles supplied through the ground-fault circuit interrupter shall be marked ?GFCI Protected? and ?No Equipment Ground.? An equipment grounding conductor shall not be connected between the grounding-type receptacles.
As for pulling the stickers off, well, not much I can do about that.... as long as they're on there when the inspector walks through that's good enough for me.
jwjrw
Senior Member
Yep thats all that counts... I knew at one time it needed both stickers but I havent done it in so long I forgot....
N844AA
Member
- Location
- Los Angeles
The ground wire (Equipment Grounding Conductor) is there to allow the circuit breaker to clear ground faults. The GFI receptacle will indirectly detect and clear ground faults, so the EGC is not required.
The main grounding wire from the service to the earth (Grounding Electrode Conductor) is what conducts lightning strikes to the earth. Without the GEC lightning with take many high impedance paths through the structure to earth, this cause micro arcing and fires.
- Location
- Massachusetts
Of course all of those things can and do happen even with a good connection to earth.
Yeah those stickers will fall off sooner or later:roll:
N844AA
Member
- Location
- Los Angeles
Quite true.
As long as the inspector sees 'em, I'm golden.
jaylectricity
Senior Member
- Location
- Massachusetts
- Occupation
- licensed journeyman electrician
OK, so everyone has made it quite clear on what a GFCI does, and what to do when you replace a non-grounding receptacle with a GFI, etc...
Can I ask you what it was about lightning that you thought GFCI protected against? You've already shown that you believe it's OK to ask questions, and I totally agree, which is why I'm asking this one. Send me a private message if you don't feel like posting it here.
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