I recently moved into a house that has multiple outdoor outlets eventually feeding an outdoor lighting transformer and a small waterfall pump. There is an outlet on the interior of the house first before the wiring goes outside, originally with two GFCI outlets at the end wired in parallel, like so:

Breaker -> Outlet (indoor) -> Outlet (outdoor) -> Outlet (outdoor) -> GFCI (lighting) LINE -> GFCI (pump)

My plan was to replace the first (interior) outlet with a GFCI, and then all others connected to the Load side, with modern WR rated receptacles.

Breaker -> GFCI (indoor) LOAD -> WR Outlet (outdoor) -> WR Outlet (outdoor) -> WR Outlet (lighting) -> WR Outlet (pump)

The outdoor wiring is direct burial (not in conduit), and based on the condition of the outdoor receptacles I'd say is about the age of the house (c. 1975). The markings are "E30445 (UL) AWG 14 CU 2 CDR WITH AWG 14 GROUND TYPE UF-B 600 VOLTS SUNLIGHT RESISTANT". Most, if not all, of the outdoor outlets were plain old 1970's indoor-spec (non-WR), which were rusted, corroded and in some cases cracked (and yes, they were all still hot!). Note: the first two outlets are typically unused, and used only for the occasional leaf blower or some temporary outdoor device.

I have two separate but related questions/issues:

  1. Is it fine, better or worse to have all of these outlets protected by a single upstream GFCI? The installation instructions for both lighting transformer and pump explicitly say they should be plugged in to a GFCI receptacle directly, which I assume is why it was done the way it was. What I've read (link, link) the issue with GFCI's in series is the nuisance of having to determine which load caused the fault. I'm not clear if having a second GFCI (in parallel) with the lighting/pump plugged directly in, if there is a GFCI upstream, is required or adds any additional safety.

  2. When I replaced the first/indoor outlet with the GFCI (a Leviton GFTR1) as shown, it immediately faulted. I disconnected each outlet up the chain and once I disconnected the last outlet (pump), it stopped faulting and was fine for the past 4 months. Last week I had turned off the breaker, and when I turned it back on the GFCI faulted and wouldn't turn back on for two days (though everything was fine until I turned power off and then back on a few minutes later). I had just had some landscaping done, and so the ground had been super-watered, not sure if that would have had anything to do with it. Once it came back, it has not faulted again. My question then is... is this a problem or concern, or is this more characteristic of the high sensitivity of a modern GFCI with older outdoor buried wiring? As in, so long as the GFCI remains on is it safe to keep in operation?


  • The buried wiring, what is the cable type? I.e. what markings? Commented Jul 8, 2021 at 14:42
  • I'm mainly interested in if it's NM or UF cable. UF is very wide/thin and the wires are embedded in the plastic jacket. NM has an outer sheath that merely wraps around the wires, and paper packing around the ground wire. Commented Jul 8, 2021 at 15:16
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    @Harper-ReinstateMonica wait, found it: "E30445 (UL) AWG 14 CU 2 CDR WITH AWG 14 GROUND TYPE UF-B 600 VOLTS SUNLIGHT RESISTANT".
    – 640KB
    Commented Jul 8, 2021 at 15:25
  • 1
    That cable should be fine for another decade at least, probably two. It has no priority compared to the rest of the situation.
    – Mast
    Commented Jul 9, 2021 at 8:11

2 Answers 2


Is it fine, better or worse to have all of these outlets protected by a single upstream GFCI?

Definitely better inside. A GFCI contains sensitive electronics that will normally last much longer inside in controlled temperature and away from rain, snow, dust, wind, etc.

The instructions are either unclear (extremely common) or it may be that they do specifically refer to a "GFCI receptacle" because with many older houses that is by far the easiest way to add GFCI protection. But (a) if you have multiple GFCI in a circuit with one feeding off the Load connections of another then you do have the multiple trip problem and (b) the protection is identical whether at every receptacle, first outside receptacle, last (or any) inside receptacle or breaker. General recommendation is "last inside receptacle" because that protects the outside, is generally (based on typical circuit layout) easiest to "match" to the outside for reset when needed and is usually less expensive than a GFCI breaker.

When I replaced the first/indoor outlet with the GFCI (a Leviton GFTR1) as shown, it immediately faulted.

Perfect! The GFCI is doing its job as designed. It protected from a faulty pump. It later protected from typical water problems. "Older outdoor buried wiring" is not the problem - though a problem in that wiring would indeed trip the GFCI. You have the far more typical "pump gone bad" and "water got into stuff" problems. The water dried up and that particular problem went away. The GFCI is doing what it is supposed to do. Yes, newer GFCIs are often more sensitive than older ones. But given the scenario - outside with water - that is a very good thing.

There are exceptions. Typical is a refrigerator or a fire alarm control panel. Both have life-safety consequences (unknown food spoilage, unannounced fire) and so there are some exceptions with respect to AFCI and GFCI for those devices. Safety is always a balance - can't make the entire plane as durable as the "black box" because it would (literally) never fly. But outdoor stuff on GFCI? Hard to see any downside - if an old pump or wires need replacement, that's better than people needing replacement.

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    Got it, so I'll go ahead and use the plain WR receptacles for the pump and lighting.
    – 640KB
    Commented Jul 8, 2021 at 14:54
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    One other thing to note though, the pump is switched and would have been off when the GFCI tripped the first time. Also, it was actually unplugged when the GFCI tripped the second time (and wouldn't reset). It was only after I waited 2-3 days and tried it again did it stay on, but nothing had changed...
    – 640KB
    Commented Jul 8, 2021 at 14:56
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    On the pump switch, is both hot and neutral switched? Because the GFCI is monitoring both hot and neutral. Most of the time switches are wired to only disconnect hot, which does not isolate the equipment at all. Commented Jul 8, 2021 at 15:11
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    @Harper-ReinstateMonica In conclusion then, It sounds like this is the kind of thing to keep on watch, if the GFCI continues to fault in the future (with the pump unplugged) then the issue is wiring related. If not, then it was just a fluke or I replace the pump someday (not nearly as expensive as trenching up the lawn!). Thanks!
    – 640KB
    Commented Jul 8, 2021 at 15:42
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    "open hot" sounds like something one of those Magic 8-ball testers would say. Those things are not made to troubleshoot old wiring, and are worthless for that task. They are for checking new construction for wiring mistakes, and are by no means conclusive (they don't list every fault). However on a classic magic 8-ball tester, "open hot" means no lights at all, which simply means hot is disconnected. Commented Jul 8, 2021 at 15:58

When several GFCI receptacles are in a circuit, all daisy-chained off "LINE", and with the "Load" terminals not used... that means nothing is protected except things plugged into those sockets.

Whereas anything hooked to the "LOAD" side of any GFCI device will protect everything - the wires, the sockets, and the things plugged into the sockets. We prefer that because of elegant economies: It means protecting more with fewer expensive GFCI devices, and it means getting the GFCI out of the rain. And protecting more stuff (e.g. the wires and sockets) is always better. Right?

Of course, when we protect more stuff, we increase our risk of a trip. You are adding a bunch of stuff (mainly: wiring) that was never GFCI protected before. This stuff may have a pre-existing ground fault, that had been present all along. That will cause the new GFCI to trip and be unable to reset.

So it often necessitates a "bug hunt" into the existing circuit to find this ground fault that has always been there. Just like any other detector: if you get a radon or CO detector and it immediately goes off, you know you had the problem all along.

  • 1
    If a new detector immediately goes off when installed, it doesn't necessarily mean there's a preexisting problem (although it usually does); it could mean that you bought a faulty detector. (Just being pedantic.)
    – Vikki
    Commented Jul 9, 2021 at 0:21
  • Occams razor always has a sharp blade. Commented Jul 9, 2021 at 0:24
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    @Vikki and if you want to be pedantic, "we haven't conclusively ruled out vaccines causing autism". But the problem with both those statements is they are extremely improbable... but due to cognitive bias, we have a population who is spring-loaded to believe them. Hang out on here awhile- the vast majority of GFCI trip-ees have that inexplicable and irrational bias toward "faulty GFCI". So your pedantic assertion is not a lie, but it has the same popular effect as a lie. Commented Jul 9, 2021 at 15:45

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