GFCI basics and help needed... - Page 1
Forum section: electronics / beginners

author: edy
author_rank: Super Contributor
timestamp: April 19, 2017, 10:24:03 pm
content: Hi,I have a number of outlets along my kitchen counter (4 to be exact). They are regular outlets, not GFCI type.Recently I found out that they were wired a strange way when a hotplate plugged into the bottom plug of an outlet blew a mains fuse down in the basement. I noticed that ALL of the bottom plugs on all 4 kitchen outlets were no longer working! But the top plugs of each outlet still functioned ok!That's when I realized that they wired all the bottom kitchen plugs (for the 4 outlets) to one fuse, and all the top kitchen plugs (for the same 4 outlets) to another fuse. Is that normal practice?So I want to replace the outlet with a GFCI and I'm not sure how that is going to work. Seems that in my kitchen, the electrician decided to make each top plug of each of the 4 outlets share a circuit, and the bottom plugs share a circuit. If I use a GFCI does it usually use one of the circuits with both top and bottom plugs share common neutral and live? I hope I'm making sense.I'll do some more investigation at home also and see what is happening with my kitchen outlets and when I flip on/off the fuses and why in the world it was done this way.NOTE:I just saw a wiring diagram where I may be able to protect all of the kitchen outlets using 1 or 2 GFCI outlets. If I use one of the GFCI's to protect all the other bottom plugs of the remaining outlets, and another GFCI to protect the top plugs of all remaining outlets. I just have to find where the source enters the kitchen and then connect to the GFCI "line" terminals, and then chain the rest to the "load" terminal as shown below:https://www.do-it-yourself-help.com/images/install-gfci-plug.gif

author: james_s
author_rank: Super Contributor
timestamp: April 19, 2017, 10:35:44 pm
content: While not all that common, I have seen this before. It's done this way so that you can pull the full 15A from both the top and bottom section simultaneously without tripping the breaker. Say you have a microwave oven and a toaster, or a toaster and a waffle iron, etc that you want to use at the same time. In my kitchen I have to be careful to coordinate use or I trip the breaker.You won't be able to split GFCIs like this, so a couple of options I can think of:- Install a dual-gang box in the first of the run and put two GFCI receptacles in there, one on each circuit.- Install a GFCI on the first receptacle, and wire nut the other circuit together as a passthrough, then install a GFCI receptacle on that circuit in the next box over, passing the first one through. That will require some investigation to determine where the run starts in order to ensure that all kitchen receptacles are downstream of the GFCIs.- Leave the receptacles alone and replace the breakers that feed them with GFCI breakers in the panel. This is what I would personally be inclined to do, I hate hunting for reset buttons on individual receptacles and prefer to have everything centralized.As with anything of this nature, refer to your local electrical codes over any advice given in a forum including mine. Talk to an inspector if necessary or hire a licensed electrician if you have any doubts about doing the job yourself.Edit: I see you've updated your original post since I replied. The diagram you show is the usual way of wiring GFCI receptacles, except that in your case it sounds like you have two runs sharing the same boxes, which will require two GFCIs.

author: Nusa
author_rank: Super Contributor
timestamp: April 19, 2017, 10:56:38 pm
content: Dual outlets almost always have removable tabs so you can put each outlet on different circuits. Sometimes this is done so you can have one switched outlet and one unswitched one.The year your house was built could be an indicator. If it's an old house and the kitchen electric was redone, it could have been a request from the owner at the time, having suffered with a single kitchen outlet for almost everything.When you're all done with whatever you do, I suggest getting out the labelmaker and marking which outlet is on which circuit, for your own information.

author: ratio
author_rank: Regular Contributor
timestamp: April 20, 2017, 12:12:21 am
content: If the GFCIs share the neutral you will have a hard time separating them. It might be possible to find a two-pole GFCI breaker, but it must be rated for personnel protection, i.e. trip at 5 mA (IIRC), as opposed to an equipment protection device, which has a higher trip point. Easiest I think would be to rewire it to alternating circuits & use normal GFCI devices-you should have all the wires you need already.

author: mmagin
author_rank: Frequent Contributor
timestamp: April 20, 2017, 12:26:51 am
content: Another twist to be aware of: At least in the US (probably Canada too), with split phase 120/240, it is common and acceptable to save on wire by using a 2-pole breaker (it must be common-trip, not handle tie!), and running a single shared neutral and two hots from the two sides of the 240 to serve a pair of 20 amp circuits, particularly common in kitchens.http://ecmweb.com/content/multiwire-branch-circuits-can-be-dangerous

author: james_s
author_rank: Super Contributor
timestamp: April 20, 2017, 01:10:43 am
content: Doh! I forgot about the possibility of a shared neutral. Yes definitely take this into consideration. If you do in fact have a shared neutral then you have a lot fewer options. Some other good points there as well.One bit of my earlier advice that does still apply though is if in doubt, call an electrician. You really don't want to be guessing when it comes to this sort of thing.

author: Paul Moir
author_rank: Frequent Contributor
timestamp: April 20, 2017, 02:42:05 am
content: He mentions fuses, so this is likely an old glass fuse panel? If this is the case a pony panel with a 2 pole gfci breaker may make sense since it's the easiest. It would be a lot better than the fuses which, while they're together in a single holder for "switching off both circuits at once" can have one blow yet have a live circuit in the box.Still, I'd be thinking $200 in materials since that's not a cheap breaker. It also makes resetting inconvenient but hopefully you aren't doing that too often.That wiring is known as "split outlets" around here, and was very common. It used to be an expensive option where (almost) one circuit was wired per outlet. Kind of went away when copper got expensive and those mini breakers came in. It was much easier and cheaper to wire a single phase 20A circuit with one of those ugly 20A GFCI outlets and use mini-breakers to halve the panel cost. Note US rules reg GFCIs in the kitchen are a little different which makes a big difference here.EDIT: If you're looking to GFCI just one of the outlets, say near the sink, then just replace the split plug in it with the GFCI and only wire up one phase to it. The other wire can just be capped or if it's in the middle of the circuit left connected to it's respective carry with the pigtail removed. You'll only have one circuit on it but it'll be a lot cheaper than buying a breaker.

author: edy
author_rank: Super Contributor
timestamp: April 20, 2017, 05:22:45 am
content: Thanks for the help so far.... I'll elaborate more once I can test out and see how the outlets are wired up.As far as the "fuses" question, what I meant to say was the breaker panel (I don't have actual glass fuses). Please see the attached photo. You'll notice how the kitchen counter plugs are labelled on the breaker panel.There are 2 places labelled for kitchen counter plugs... a) between where it says "dishwasher" and "microwave" (the adjacent switches are connected by a metal rod). And (b) between where it says "hallway/bathroom" and "garage" (also the adjacent kitchen counter switches are connected by the metal rod). The metal rod is flexible meaning that if one of the breaker switches of the kitchen counter pair trips, the other doesn't necessarily get pushed over. I can have one or the other breaker switch connected by the metal rod on or off.... I'm not sure what purpose the rod has unless for safety to remind the user to turn both off when working on them in the kitchen. Also not sure why they decided to put them on separate breaker "modules" like that instead of the same one (i.e. why did they order it "dishwasher"/"kitchen counter plug", "kitchen counter plug"/"microwave"... and not "kitchen counter plug"/"kitchen counter plug" and then have "dishwasher"/"microwave" on the next).When the bottom kitchen counter plug tripped the breaker, only one breaker switch of the pair connected by the metal rod had tripped off. I assume that the other breaker switch is for the top plugs. Also, the fact that I have 2 of these "kitchen counter" breaker pairs means that I may have some of the plugs connected to one pair of breakers, and other kitchen counter plugs connected to the other pair of rod-connected adjacent breakers.I will have to figure out the wiring by turning on one breaker at a time from each pari and seeing which plugs are active in the kitchen, assuming they are labelled correctly and that it is not also powering other plugs (like the fridge, which I did not see a label for).Anyways, after some further research I see this is a common issue that people want to convert a "kitchen split receptacle circuit" to a GFCI plug. I see someone posted a similar thread on this forum:http://www.diychatroom.com/f18/kitchen-counter-convert-standard-split-receptacle-two-gfci-receptacles-340289/Also this provides some insight:

author: Monkeh
author_rank: Super Contributor
timestamp: April 20, 2017, 05:38:58 pm
content: The reason for the circuit ordering is that those are double-density breakers. Each apparent pair ison the same phase.