Two GFCI's On Same Branch ?

Hello,
First, thank you all very much for the GFCI comments and information. Appreciate it very much.
Thought I'd start a new thread with this, as the previous one is pretty
long.
Should have asked this question on that thread, but forgot to.
I understand that a single wall mounted GFCI will in theory protect all the outlets "downstream" from it (the GFCI being wired as Line-In, and then Load-Out to the other regular downstream outlets)
Question: even though not needed, is there any harm done if there is another GFCI on the same branch, also wired as Line-In Load-Out ?
In other words you would have: GFCI No. 1 Line-In, and Load-Out to GFCI No. 2 Line-In and finally its Load-Out then to a regular outlet
Realize the second GFCI is redundant and not needed.
But, e.g., do they fight each other, more prone to inadvertent tripping, or... ?
Thanks, Bob
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Robert11 wrote:

Shouldn't be a problem.
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I've seen it, and not seen any problem with it. Just can get confusing if you don't know to look for the second GFCI if it trips and you don't know about it. There are a lot of appliances now with their own built-in GFCI, like hair dryers, and these are often plugged into GFCI protected circuits.
Bill Ranck Blacksburg, Va.
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Indeed!
The "confusion" IS the problem. The "next guy" to deal with your house might go crazy finguring out why the GFCI circuit is dead.
Otherwise, there is no "safety" or false trip problem. The "self-test" function onl loops back within the same GFCI so "series" GFCIs will "test" OK.
If you use a separate tester with a push button, you might "trip" either GFCI and if Murphy is about, you will test the downstream GFCI and trip the upstream one you don't know about.

The window AC I got 2 summers ago has a GFCI plug. It only has 2 conductors to the A/C proper which means that the metal case is "floating." It has tripped a few times but not often enough to be a PITA.

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Robert11 wrote:

I've seen it done, it works, the only real issue is having to walk around and figure out which one tripped, there's really no good reason I can think of to do it this way.
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| First, thank you all very much for the GFCI comments and information. | Appreciate it very much. | | Thought I'd start a new thread with this, as the previous one is pretty | long. | | Should have asked this question on that thread, but forgot to. | | I understand that a single wall mounted GFCI will in theory protect all | the outlets "downstream" from it (the GFCI being wired as Line-In, and then | Load-Out to the other regular downstream outlets) | | Question: even though not needed, is there any harm done if there is | another GFCI on the same branch, also wired as Line-In Load-Out ? | | In other words you would have: GFCI No. 1 Line-In, and Load-Out to | GFCI No. 2 Line-In and finally its Load-Out then to a regular outlet | | Realize the second GFCI is redundant and not needed. | | But, e.g., do they fight each other, more prone to inadvertent tripping, | or... ?
They would not be more prone to tripping. But if they trip at the same leakage current level, you can readily see both trip when the leakage is downstream from the 2nd one.
My intent for a house I'm designing is to wire every outlet in the kitchen on a separate circuit. That way if one trips, it doesn't cut half the kitchen off.
The coming increased use of AFCI protection on circuits could involve the kitchen circuits. It seems most AFCI breakers include GFCI protection as well. The ones I was looking at from Cutler-Hammer do this at the people protection level. I didn't see any that do not have GFCI protection. They also have 2-pole versions (so I can apply the protection also on 240 volt circuits). So I'm trying to work out the design to have the breaker panel near the kitchen. And I won't need any GFCI outlets.
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| |> Hello, |> |> First, thank you all very much for the GFCI comments and information. |> Appreciate it very much. |> |> Thought I'd start a new thread with this, as the previous one is pretty |> long. |> |> Should have asked this question on that thread, but forgot to. |> |> I understand that a single wall mounted GFCI will in theory protect all |> the outlets "downstream" from it (the GFCI being wired as Line-In, and |> then Load-Out to the other regular downstream outlets) |> | | There is no theory to it. Connect the supply side to the LINE taps, and the | rest of the circuit on the LOAD side, and everything down stream will be | protected.
Of course there is theory. Theory assumes the devices are designed correctly, manufactured correctly, and installed correctly. Just because this really does happen 99% of the time does not mean nothing can go wrong the other 1% of the time. People use the term "in theory" to describe the expected/intended operation. It doesn't always happen that way.
|> Question: even though not needed, is there any harm done if there is |> another GFCI on the same branch, also wired as Line-In Load-Out ? |> |> In other words you would have: GFCI No. 1 Line-In, and Load-Out to |> GFCI No. 2 Line-In and finally its Load-Out then to a regular outlet |> | | Why would you even consider doing that? A standard outlet costs about $0.75 | (you can buy them for as low as $0.49 if you shop, and maybe even lower if | you buy in bulk) and the GFCI costs in excess ten times that.
Maybe he was thinking he'd have better protection against failure from cheap imported devices. Or maybe he just wanted all the outlets to look the same. My own personal goal is to make them all look the same. If I were doing a string of outlets (instead of my plan to have each on a separate branch), then I would have each string on a GFCI that was out of view, such as on a wall around the corner from the kitchen or something like that.
OTOH, given the likely use of AFCI breakers on all those kitchen circuits, and that all the AFCI breakers in the panel series (CH) I expect to use do have GFCI people protection included, I will use "ordinary" looking American style outlets in the kitchen.
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| By that argument, the GFCI either works or it doesn't. If it works, | everything downstream is protected. There is no theory to it. If it doesn't | work, nothing else matters.
And thus, that is the theory. In theory, it will work. In practice, we'll have to see.
| I assume the device works properly, when it it trips, I fix the fault that | is tripping it, when it does not trip, I put in a new one.
If you're still alive to put it in.
|> |> Question: even though not needed, is there any harm done if there is |> |> another GFCI on the same branch, also wired as Line-In Load-Out ? |> |> |> |> In other words you would have: GFCI No. 1 Line-In, and Load-Out to |> |> GFCI No. 2 Line-In and finally its Load-Out then to a regular outlet |> |> |> | |> | Why would you even consider doing that? A standard outlet costs about |> $0.75 |> | (you can buy them for as low as $0.49 if you shop, and maybe even lower |> if |> | you buy in bulk) and the GFCI costs in excess ten times that. |> |> Maybe he was thinking he'd have better protection against failure from |> cheap |> imported devices. Or maybe he just wanted all the outlets to look the |> same. |> My own personal goal is to make them all look the same. If I were doing a |> string of outlets (instead of my plan to have each on a separate branch), |> then |> I would have each string on a GFCI that was out of view, such as on a wall |> around the corner from the kitchen or something like that. |> | | He might be thinking that, but he would be wrong. Two GFCIs do not provide | twice the protection, they only provide twice the number of places to check | for a reset button.
If one of them fails to interrupt the circuit because it is faulty, and leaves the circuit energized, and the other one works OK and interrupts the circuit, that is at least full protection in a circumstance where one alone may be providing less that full protection. Two is more than one.
| Why not just use the Decora-type outlets that have the same form factor as | the square GFCI outlet? You can also combinne them with the paddle-type wall | switches. Now, all or your face plates are the same shape, except for the | ones that are doubles or tripples, then those are the same shape but longer.
If you find any for NEMA 6-15, let me know.
| Why on earth do you want a separate circuit for each outlet in the kitchen?
I already gave one explanation. The one I gave was that I do not want half the kitchen shutting off if one gets tripped for some reason (and with AFCI breakers involved, there are now more reasons for that to happen).
Another reason is I don't want to have to consider how my loads get balanced in the case I need more than one circuit can handle. I'd have to be sure that someone won't plug two 1500 watt cookers into the same circuit and end up with that circuit shutting off in 10 minutes when no one is around to notice.
| That is costly and inefficient all at the same time. If you consider the | fact that most kitchen outlets spend their entire lives unused, then you | would not do what you are planning. And, when a kitchen outlet is being | used, it has a coffee maker in one, a toaster oven in another, and a blender | in the third. What are the odds you will blend a margarita, brew coffee, and | cook a bagel all at the same time?
See above. The cookers can run for 3 to 4 hours. Sure, they will kick on and off. But sometimes they will come on together, and their duration on could be long enough that together they take the breaker beyond its thermal trip point, especially after it is well warmed up with an hour of usage.
| The load of the breaker is 15A, and the load of any of these items is about | 2A, maybe 3A. You could easily save money by putting in two or three | circuits instead of a separate circuit for each outlet. Loop the 'fridge and | the garbage disposal on the same circuit, and maybe include the dishwasher. | This would be a reliable circuit.
No. The load of the breaker is 20A (this is a kitchen) per code. And the load of the cookers is nearly enough to need a dedicated circuit. Who knows what will happen when things get hectic with multiple chefs such as a large family gathering one or two days a years (it needs to all work on those days with peak demand).
| I've not read the blueprints for the houses we build, so I don't know how | they divide up the various loads. I get that you want to never blow a | breaker, and you may want far more capacity than a general builder normally | gives. But, I am sure you do not want a separate circuit for every outlet. | You will run out of space in the breaker box in a hurry if you load it up | with breakers that only go one place.
With my dad's house I'm staying in right now, there are 8 kitchen outlets on 2 circuits. The first 2 have GFCI outlets. The rest are strung from there (the usual scheme). They alternate as you follow them around the kitchen and onto the island. If I trip one, every other outlet goes out.
| Instead of making a leg go to every outlet, make two or three extra legs to | the kitchen and make more outlets than anybody has ever seen. One leg can | serve 5 or 6 outlets, so cut that back by one and add one or two extra legs. | That makes more sense to me than loading the panel with breakers that only | go one place.
The same problem will still exist.
| I'm not sure, but I don't think the AFCI breakers in the box are suitable | for GFCI locations, or they would already be using them instead of using | both in the same house. I worked for new home builder, and the code here is | that wet locations must be GFCI protected, and the bedroom circuits must be | AFCI protected. If AFCI filled the bill for a wet location, I'd expect the | people that create and/or enforce the code to want one type of circuit, and | the builder to only want one type of circuit too.
Why would a general contractor building a spec house ever use anything more than the code requires? If the code merely requires GFCI protection in some location, and does not require AFCI, why would they put in AFCI even if it would work. Then the average homeowner has no idea, so they would not be replacing them.
Check the new code coming to an AHJ near you soon. AFCI is being required in more locations. If AFCI is not required in kitchen circuits when I build my house, I will consider not using them. A factor in that decision is how well they work in future designs. They do offer a protection I consider to be helpful in a kitchen. They still have a tendency to false tripping such as unplugging a plug slowly under load. If by that time AFCI is required in the kitchen, then they will be used.
But, don't assume that the lack of using AFCI for wet areas means they don't have GFCI protection as part of their operation. The technical specs for the Cutler-Hammer AFCI breakers clearly describe their 5ma people protection GFCI protection included in their AFCI breakers.
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| |> wrote: |> |> | By that argument, the GFCI either works or it doesn't. If it works, |> | everything downstream is protected. There is no theory to it. If it |> doesn't |> | work, nothing else matters. |> |> And thus, that is the theory. In theory, it will work. In practice, |> we'll have to see. |> | | If the GFCI works, everything downstream is protected. There is no theory to | it.
In theory, it works.
| You are hereby a full fledged idiot. I pray nobody takes advise from you, or | has you design circuits for them.
My advice to them would be not use use cheap imported junk.
My advice would also include ingnoring the guy that makes false claims about what the code prohibits.
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