# 110v GFCI arrangement



## CliffyJ (Apr 29, 2009)

I currently have a single 110 GFCI outlet to service the layout, but would like to put in a few more to make things easier. For example, plugging in future control gear, power tools, work lights, and electric garden tools. 

I have a dedicated 15 amp line going out to a single outdoor GFCI. I'll add 3 more outlets from there. Code-wise & technically, I have a choice to (#1) make those 3 new receptacles all independent GFCI's, or (#2) slave them to (the "load" terminals of) the present GFCI. 

Here's some diagrams for reference. My #1 corresponds to the first figure, except that it would be 4 GFCI's (no slaved duplex). My #2 corresponds to the second figure.

http://www.do-it-yourself-help.com/gfci_wiring_diagrams.html

Are there any reasons I should go with #1, independent GFCI's? The only benefit I can think of for the #1 route is that if you expect faulty grounds, or multiple extension cords laying around in the rain, only one receptacle would trip, and the others would remain powered. But I don't want that. If there's ANY fault, or cord in a puddle, or whatever, I want all the outlets to shut down. And that leads me back to #2. 

I've tried to find info on the pro's and con's, but so far haven't found it. I'm leaning to #2, seems like a better alerting method; and, it's less expensive..

Has anyone worked thru these matters? Anything I'm missing? 

===>Cliffy


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## Jerry McColgan (Feb 8, 2008)

I am not an electrician and codes vary from place to place.

I have multiple GFIs and some of them trip in wet weather. Some are over 20 years old. I would not bet my life on any of them - even when I sold them. If you act as if you did not have a GFI you will be safe. If you are trusting a GFI - you may be a test pilot.

If you are in a damp or wet environment working with electrical tools you are nuts - with or without a GFI.

I would first start with an inexpensive 3 wire tester and confirm that all of your outlets and 3 wire extension cords test OK. You might discover a missing ground (the round hole). If that is not connected a GFI is probably useless.

You might also check double outlets with a volt meter to be sure they are not connected to different circuit breakers. I discovered the double outlet under my sink (feeding the dishwasher) was connected to two circuit breakers resulting in 220 volts at the sink & dishwasher.

Just one person's opinion.

Jerry

ps you might be surprised if you knew who wired your house. Depending on time & location it might have been high school kids supervised(?) by an electrician. Heck I know what I am doing but I would not hire me.

pss if your GFI/GFCI (ground fault circuit interrupter) fails you DO NOT want to be the NEW GROUND that your circuit discovers.


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## CliffyJ (Apr 29, 2009)

Jim, this is a dedicated circuit to an existing GFCI. I wouldn't run line voltage equipment in a wet environment, and I don't think I'm nuts (at least on this topic).

I wired the circuit myself, and am confident in my long experience in this area. My main question remains: whether to grow that branch to independent GFCI's, or slaved duplexes. 

It sounds like you have multiple independent GFCI's. How many are outdoors? Are any duplexes slaved to them? 

Best regards,
Cliff


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## JPCaputo (Jul 26, 2009)

Another option is to use a gfi breaker on the panel. It will protect all outlets connected to it. That will be about the same cost as 2-3 decent gfi outlets. 

GFI outlets and breakers are not something to get the cheapest version. It is something that can save your life. Go for a good brand, ge, square d, abb.


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## Mike Reilley (Jan 2, 2008)

Cliffy, it's as easy as this. If you use one GFCI and daisy chain all the outlets to it, one ground fault anywhere, will shut the whole shebang down. Then, you have the burden of determining what it was that did that. 

If you put in multiple GFCI, a ground fault will only shut THAT part of your layout down...and allow the rest of your layout to keep working. This is way easier to debug.


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## CliffyJ (Apr 29, 2009)

You both raise great points, re. failure of the GFCI receptacle. I don't have any experience with one failing, and yes, if it did, it could be fatal. I TOTALLY GET THAT. 

It would be good option to replace the breaker feeding that outdoor circuit with a good quality GFCI version. Or, ensure that the first GFCI "distribution" receptacle is of a good quality. Either way, all the downstream outlets would be simple duplexes in wp boxes (and not redundant GFCI receptacles).


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## CliffyJ (Apr 29, 2009)

Mike Reilley said:


> Cliffy, it's as easy as this. If you use one GFCI and daisy chain all the outlets to it, one ground fault anywhere, will shut the whole shebang down. Then, you have the burden of determining what it was that did that.
> 
> If you put in multiple GFCI, a ground fault will only shut THAT part of your layout down...and allow the rest of your layout to keep working. This is way easier to debug.


Thanks Mikey, you've answered / confirmed my big issue.


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## Semper Vaporo (Jan 2, 2008)

A GFCI works by detecting the difference in current flowing in the "Hot" (Black or Red) lead (the shorter of the two rectangular holes in a socket) and the current flowing in the "Neutral" (White) lead (the taller of the two rectangular holes), regardless of whether the "Ground" (Green or Bare) lead (the round hole) is connected or not. If there is a difference for more than one half of the 60 Hz cycle it disconnects the power on the HOT lead. It does not take into account current flowing in the "Ground" lead.

It is only measuring the current flowing in the Hot and Neutral leads. Any difference in the two currents and it disconnects the power.

It doesn't matter if the "missing" current came back via the "Ground" lead or shorted directly to the Earth ground (via a mud puddle or a person hanging on to the cold water pipe and the metal case of an electrical device that is supposed to be insulated from the "Hot" lead). It merely detects that current went out and didn't come back the way it was supposed to.

You are protected even if your device only has the Hot and Neutral leads. They do protect you! I can attest to that. My OLD GE electric drill shorted to the metal case (not a Double-insulated tool) and I never felt a thing... it just stopped working. I went to the GFCI and reset it and when I "gingerly" touched the case of the drill again, the GFCI tripped immediately and again I didn't feel at thing... except extreme gratitude to the inventor of the GFCI device.

Can you still be hurt even if using one of these things? YES! But the chances are considerably reduced. I still would not stand in a puddle and use even a double-insulated drill, but I know they work!


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## Jerry McColgan (Feb 8, 2008)

CliffyJ said:


> It sounds like you have multiple independent GFCI's. How many are outdoors? Are any duplexes slaved to them?
> 
> Best regards,
> Cliff


My GFCIs & my knowledge predate what is available today. They are independent (in wall or in extension cords). Others can probably give better advice on newer stuff. 

*BTW. I was joking. Nuts & test pilot were simply substitutes for emoticons. * 

Good luck,

Jerry


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## Michael Glavin (Jan 2, 2009)

Cliff

Based on your wants #2 with multiple slaved receptacles is what you want. Less expensive and protection for the lot.

Only reason you might want multiple GFCI's is for convenience, when one pops, its obvious and the others soldier on.

The only problem or concern I see herein is the 15 amp circuit feeding the lot, if the circuit capacity suffices for your load needs so be it. 

Jerry,

Its very common, to provide two circuits to a single duplex receptacle in said circumstance; one is for the dishwasher and one is for the garbage disposal, nuff said. The dishwasher in of itself needs at least a 15 Amp circuit (electric heating elements). So it was not a mistake but someone new what they were doing. Each circuit would be 115/120V. And it would only measure 220/230V if you measured at each upper/lower load terminal simultaneously of the split receptacle and the circuits were not from the same BUSS, i.e., L1 and/or L2. FWIW this is also common in bedrooms, upper receptacle socket works for lamp controlled via light switch and lower socket powered on 24/7 for whatever (could be same circuit feeding upper/lower socket or an additional circuit).

Michael


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## CliffyJ (Apr 29, 2009)

Thanks guys, I really appreciate your taking the time to address this. 

These are utility outlets that will serve only one occasional device in one location or another. Like a glorified extension cord. It all has to be bullet-proof safe, to the extent possible. I should have said that earlier, but it only just occurred to me to say it like that.

Mikey and Michael, thanks, I'll be heading in the direction you describe. I'll only have one or two things drawing current from the entire circuit, at any one time. My main issue is availability of the receptacles.

Thanks brothers,
CJ


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## Greg Elmassian (Jan 3, 2008)

By the way, GFCI's don't weather well (I have about 6 outside), so if it is a dedicated circuit, consider using a GFCI breaker, much nicer, I have the outdoor unit die every so many years.

Greg


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## Jerry McColgan (Feb 8, 2008)

Michael Glavin said:


> Jerry,
> 
> Its very common, to provide two circuits to a single duplex receptacle in said circumstance; one is for the dishwasher and one is for the garbage disposal, nuff said. The dishwasher in of itself needs at least a 15 Amp circuit (electric heating elements). So it was not a mistake but someone new what they were doing. Each circuit would be 115/120V. And it would only measure 220/230V if you measured at each upper/lower load terminal simultaneously of the split receptacle and the circuits were not from the same BUSS, i.e., L1 and/or L2. FWIW this is also common in bedrooms, upper receptacle socket works for lamp controlled via light switch and lower socket powered on 24/7 for whatever (could be same circuit feeding upper/lower socket or an additional circuit).
> 
> Michael


Hi Michael,

I am glad to know that. Unfortunately I happened to be on my elbows in leaking dishwater when I discovered the outlet I thought I had turned off was still hot. 

Sometimes I feel safer with 25 kV than with 120 VAC. 

I am always happy to admit it when I get it wrong.

Thanks,

Jerry


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## Semper Vaporo (Jan 2, 2008)

My son-in-law got into trouble with his house being wired with 240V in each duplex outlet. He had to replace an outlet due to damage and didn't know that when the two sockets are wired separately you have to cut that little joining bar between the screw terminals... he put it in, plugged in the microwave and the coffee maker and then then went to the breaker box and turned on the breakers (he had shut off both circuits, thankfully). When he turned on the breakers that put a dead short on the 240 Volts circuit which vaporized the joining bar, but it also somehow managed to get 240 Volts on both the coffee maker and the microwave and destroyed them too. Expensive mistake! And lucky he didn't burn the house down from the flash!

Just recently they asked for help with another socket that they wanted moved. I didn't know the details of the previous problem. When I got there this time I was confused by the number of wires in the junction box. It made no sense. 6 wires in and 6 wires out. That was when I figured out that it was two circuits in and they were daisy-chained out to the next outlet further along the wall. (The 6 wires were two Hots, two Neutrals and two Grounds) He had already removed the outlet that was in the box and discarded it so I could not verify that it had the joining bar removed and the box was wired with 220. I guessed that it was and that the joining bar had been removed but we had to turn all power back on (with all those bare wires sticking out!) and I used a Volt meter to test it out and prove it to myself.

I had never seen a house wired that way, but it has taught me a lesson to be sure to check BOTH sockets in a duplex outlet before I decide that power has been removed so I can work on it. (Frankly, I don't like wiring things that way!)


BTW: Does anybody know why years ago (pre 1950's) house power was specified as "110/220" and then in the '50's, and '60's it was referred to as "115/230" and now today it has transitioned to "120/240 Volts"?

I'll wait to see if anybody knows...


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## Greg Elmassian (Jan 3, 2008)

http://files.engineering.com/downlo...8f15cb184&file=ANSI_C84_and_208_V_systems.pdf


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## krs (Feb 29, 2008)

Semper Vaporo said:


> I had never seen a house wired that way, but it has taught me a lesson to be sure to check BOTH sockets in a duplex outlet before I decide that power has been removed so I can work on it. (Frankly, I don't like wiring things that way!)


Split receptacles are always supposed to be protected with either a double-pole breaker or two single pole breakers that are mechanically connected (or the equivalent if there are still fuses), so if one removes or trips the breaker, both halves of the receptacles will always be without power.
But it sure doesn't hurt to check with a voltmeter

Knut


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## denray (Jan 5, 2008)

Cliff I totally agree with Mike
Dennis


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## Treeman (Jan 6, 2008)

You will have less nuisance tripping with independant GFCI's. As you add more wiring downstream you have more points to leak, the amount of current required to trip is so slight this is often a problem, especially outside in damp or wet locations.


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## krs (Feb 29, 2008)

The whole purpose of GFI's is to use them around wet and damp locations.
Code usually requires them around swimming pools, bathrooms, kitchens.
I can't recall any nisance trips for the ones I have.


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## Ted Doskaris (Oct 7, 2008)

As to house wiring, 240 V ac is the power drop with 240 V ac circuits provided for an electric dryer and stove, etc., and the 240 V ac is split in two 120 V ac legs with approximately half the 120 V ac house circuits on each leg. If by happenstance you were to wire independent 120 V ac circuits from opposite legs and have their outlets physically near each other you could have 240 V ac across each of the hot terminals. Though this is something that one would not typically do and GFCI would still seemingly work, it would seem good practice to use only the same 120 V ac leg in an a given outdoor area.

Just a thought,
-Ted


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## Greg Elmassian (Jan 3, 2008)

What you say makes sense Ted, and would be the way to do it.

But I can tell you from direct observation that often when several circuits are run somewhere (like my house) they bring all the wires back to the panel and don't really pay attention to which "phase" they are connected to, in fact, when adding a number of new circuits, the added breakers present an alternating "phase" in terms of the screw terminals on the new breakers.

Typically, both outlets in a normal duplex are on the same circuit, but also usually, in a quad box, 2 different circuits are presented.

Greg


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## Ted Doskaris (Oct 7, 2008)

Hi Greg, 

What got me to thinking about this was the "Semper Vaporo" story about his son-in-law's disasterist wiring.

I agree its likely any new circuits added would be of alternating phase given the power panel layout which relates to my observation. 

Anyway, if an existing outdoor circuit is already present and one decided to add another circuit from the power panel near the existing circuit, that's what I was thinking about - though not likely someone would do this unless concerned with tripping the breaker with too much load from the existing circuit.

-Ted


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## Treeman (Jan 6, 2008)

What leg you are on makes no difference. The potential to ground is the same, 110V. Nucance tripping has been a real issue over the years. This would depend on the sensivity of each device, brands and quliaty, would enter in to the conversation.


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## Greg Elmassian (Jan 3, 2008)

I agree completely Ted, especially out doors.

As you have been to my house, you will remember the large pillars on either side of the main entrance? 

There is a conduit from the breaker panel that "daisy chains" to the closest piller, then to the next and the next.

When electricians make a "run" with 2 circuits, they often use wires that have black, white, green and red. The red is the "hot" or "line" for the second circuit.

so the first pillar power uses the black, white, green, the second pillar the red, white green, and so on (there are actually 4 circuits in the front entrance, so 2 sets of four wires).

Regards, Greg


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## Dan Pierce (Jan 2, 2008)

In Massachusetts the code does not allow more than one circuit source to be in a box. This is fun for multiple lights to keep this in mind when wiring a box with 3 switches.
Also, kitchens require 3 outlets max on a 20 amp circuit. Other 20 amp circuits can be 5 outlets.
And only 1 wire in and one wire out so the outlets are strung in a series and no junction boxes!!

Lighting circuits are a little different but still only 1 circuit/single breaker feed to a box.

I am not an electrician, but I did wire my own home and passed inspection on the first try.

On another note, only 1 GFCI is needed per circuit, ground faults in series is not a good idea as they draw power to monitor the line and can give false trips (mine have small lights). It would be a great idea to run 1 line to operate your trains and a second for power tools.

Also note that a circuit should average half the current, not have a constant full load.


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## CliffyJ (Apr 29, 2009)

Just to touch base, thanks everyone for your thoughts on this. I'm on an overseas trip, and have been limited on internet access. So please don't take my unresponsiveness for ungratefulness. 

Best regards all, and I'll chime in a few days.
===>Cliffy


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## Greg Elmassian (Jan 3, 2008)

wow Dan, that is pretty crazy, we often have more than one circuit in a box, like a quad box with 2 separate circuits for outlets, or a box that has separate lighting circuits, or a light switch and an outlet.

Greg


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## Treeman (Jan 6, 2008)

That would not be a part of the NEC.


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## Michael Glavin (Jan 2, 2009)

Dan's comments seem rather extreme, if not surprising. BUT state, regional and local jurisdictions are KING as NFPA/NEC are merely guidelines for standards and or safe electrical practices. Accordingly since there is no Federal mandates requiring adoption of said codes, they are often used as a reference/guideline influenced by regional/local anomalies for the creation of building standards/code.

As a Contractor in a specialty trade, I have to deal with NFPA codes and local (local=city and or county) interpretation on a regular basis, for the most part California Building Codes align themselves with the NFPA/NEC, yet as alluded to previously regional/local jurisdiction often amend said codes to work around specific conditions in local environments.

NFPA = National Fire Protection Association (a private trade association), publishes the NEC = National electrical Code.

Michael


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## CliffyJ (Apr 29, 2009)

Dan, are you saying that each outlet is served by a dedicated breaker? That doesn't make sense to me, because with the NEC min spacing of outlets per wall, one light socket per breaker, etc, you'd have almost a wall of circuit breaker panels. I'm sure I'm just misunderstanding though.


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## Greg Elmassian (Jan 3, 2008)

No, you cannot mix different circuits (on different breakers) in the same junction box.

Greg


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## Michael Glavin (Jan 2, 2009)

Greg,

You done confused me with your last comment?

FWIW:

According to NEC Article 210 Branch circuits:

Multiwire branch circuits and or multiple circuits derived from two single-pole circuit breakers terminating in a junction box, such as Jerry described (single duplex receptacle with common yoke/strap) for his dishwasher/garbage disposal are permitted. The only caveat now, which if I recall came into play about ten years ago is that the single pole breakers be tied together with a common trip bar OR utilization of a two pole circuit breaker (this turns off both 120V circuits to the single duplex receptacle simultaneously). 

A strap/yoke is metallic and is the metal integral fixture of which the receptacle is mounted to with ears which mounts the receptacle/light switch to a junction box.

That said if two individual receptacles and or a receptacle and lighting load is served from a common junction box again with a mutiwire branch circuit (two or more 120v circuits feeding same), single pole breakers are permissible. The determining factor herein is the receptacles or loads are uniquely separated. 

Michael


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## Greg Elmassian (Jan 3, 2008)

I may have misunderstood what Dan stated, and tried to ask an explanation.

I do completely understand what you are saying, and indeed here, we don't have that restriction, or perhaps we do, but my landscape wiring does not have that restriction, and it was all permitted.

Regards, Greg


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## JPCaputo (Jul 26, 2009)

To put it simply, if a outlet box has 2 circuits in it, the breakers in the panel need to be tied together.

That way, when you want to turn the power off to the plug, both lines in the outlet box get turned off at the same time.


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## Michael Glavin (Jan 2, 2009)

JPC,

No, its not that cut and dry. I describe above in the last paragraph its permissible to have two or more circuits in a junction box with individual single pole breakers providing the circuits do NOT share a yoke/strap. Simply stated if two circuits are connected to a single duplex receptacle the breakers need be tied together, otherwise NOT.

Michael


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## Greg Elmassian (Jan 3, 2008)

THAT rule makes more sense to me Michael... and more in parallel with what I have seen down here.

Duplex outlets are rarely split, just to keep confusion down. I do see this pretty often in server rooms.

Greg


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## Michael Glavin (Jan 2, 2009)

Greg,

I had to mull over your comment several times to see if I was interpreting said comment out of context. As you alluded to on the first page you understood it was common acceptable practice.

Michael


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## Greg Elmassian (Jan 3, 2008)

My first display page does not have a post from me.

I believe the number of posts per page is settable.

If you could refer to the post number I can see where I had a brain fart.

Greg


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## Michael Glavin (Jan 2, 2009)

Greg,

My bad, it was on page #3 for me; post #27.

Michael


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## Greg Elmassian (Jan 3, 2008)

Quad box, 2 duplex outlets, 2 different circuits, seems to be ok by the rules you quoted.

Greg



Greg Elmassian said:


> wow Dan, that is pretty crazy, we often have more than one circuit in a box, like a quad box with 2 separate circuits for outlets, or a box that has separate lighting circuits, or a light switch and an outlet.
> 
> Greg


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## Michael Glavin (Jan 2, 2009)

Greg Elmassian said:


> Quad box, 2 duplex outlets, 2 different circuits, seems to be ok by the rules you quoted.
> 
> Greg


  I concur and have experience with said practice in California.

Michael


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