Moved into a new home about 6 months ago which had been gut rehabbed.

Our mechanical room has 2 pits, one for the sump pump and another for the ejector pump.

I was planning on installing a battery backup system to our sump pump when I made a few surprising discoveries.

  • neither the ejector pump or the sump pump were on GFCI receptacles.

  • while the sump pump and the ejector pump receptacles are on different circuit breakers, the ejector pump is using a single dedicated receptacle, while the sump is on a dual receptacle, sharing with our alarm system.

my impulse was to switch each receptacle to a dual receptacle GFCI outlet, but I became skittish after seeing the single dedicated outlet for the ejector pump.

from what I understand, GFCI receptacles should be standard for this room since, by definition, we're talking about water with risk of flooding and shock.

  1. is there a particular reason the ejector has it's own dedicated outlet?

  2. if not, can a single dedicated receptacle be easily converted to a dual GFCI?

  3. if so, can the ejector pump and battery backup be on same dual GFCI outlet as I now have planned (with the sump remaining on it's own dual GFCI with the alarm, on a separate breaker)?

While I've never installed a GFCI plate before, I'm comfortable with very basic electrical and it seems pretty straightforward. however, I don't want to get in over my head or be unaware of some important point about the single receptacle, and then be faced with flooding, sewage, electrical shock... and worse, angry wife.

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    There is nothing wrong with using a duplex GFCI outlet (they are usually cheaper than single). Just don't use the other outlet for anything.
    – Ariel
    Commented Oct 26, 2014 at 3:48
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    I have strong doubts about your being able to find a UPS powerful enough to run a motor. The surge current to start a motor is far beyond what a normal UPS can deliver.
    – Ariel
    Commented Oct 26, 2014 at 3:49
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    Also might it be good practice to have the alarm on a often used (lighting) circuit thereby confirming the alarm has power when lights are used. Sort of a check engine light idea.
    – user28620
    Commented Dec 7, 2014 at 14:47

4 Answers 4


Current code leans to GFCI the heck out of it, and if it nusiance trips or fails (as they do with some regularity; typically about 10 years) and backs up sewage or water, tough noogies. People who sell GFCIs write the codes, and they have been expanding places where GFCIs are required for years. As of 2002 code (at least) there was still an exception for sump pumps and freezers, but those have been removed due to either "greater care for your safety" or "vast sums of money from GFCI makers .vs. no sums of money from people with flooded basements and freezers full of rotting food" in the code-writing cycles. [It should be self-evident that the linked page is from the side with all the profit in this game, and just a tad smug/biased.]

I would NOT change the ejector pump to a dual, nor add anything to its circuit - sewage backups stink. A dedicated breaker with one outlet is one way to be certain that nothing OTHER than a pump failure or power outage causes the ejector pump to stop; and depending on the pump, it may need the entire circuit to itself, period. Even if it does not, sharing is poor practice, IMHO. If you would like to add a GFCI to it, put in a blank face GFCI in-line before the outlet, or a GFCI breaker. If it's installed to code as of the time it was installed, I'd suggest leaving it alone, but that's up to you.

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    I wouldn't blame it all on GFCI manufacturers, and those fine folks that write the codes. Device manufacturers have had ample time to design devices that don't trip GFCIs, they simply refuse to do so.
    – Tester101
    Commented Oct 26, 2014 at 4:09
  • @Tester101 -- There's only one device I know of that is completely functionally incompatible with a GFCI, and that's the Line Impedance Stabilization Network used in labs to measure conducted RFI. Commented Jan 28, 2015 at 1:27
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    @ThreePhaseEel Not according to the countless customer support, and appliance technicians I've talk to. They seem to believe that there are quite a few devices that are incompatible with GFCIs.
    – Tester101
    Commented Jan 28, 2015 at 2:13
  • @Tester101 -- there are plenty that are considered incompatible because nobody on the engineering team cared about earth leakage. LISNs are different because they have to leak current to earth (15mA or so of it) as a side-effect of their intended function (they have large value capacitors line-to-earth, much larger than what you can get in a Y-rated safety cap). Commented Jan 30, 2015 at 0:51

There should be no technical problem just replacing both outlets with GFCI units. For end of circuit branch they install pretty much just like a regular outlet. Just make sure to connect the wires in electrical box to the "LINE" terminals of the GFCI unit.

When purchasing the GFCI units keep a lookout for the newer lower profile types that use up less back space in the electrical box. These make it much easier to mount the unit into the box leaving more room for the wires in the back.

Check the amperage ratings of the two pumps, the alarm system and the battery backup unit. You want to make sure that the total amperage allocated to each circuit does not exceed 80% of the capacity of the wiring and circuit breaker for each breaker.

I would tend to suggest that you swap the alarm system to be on the circuit with the ejector pump (within the above loading restriction of course) then place the battery backup for the sump pump to be on the same circuit as the sump pump.

  • Installing a GFCI for an older device (especially a device plugged into a single dedicated receptacle), might be a mistake. The older device is likely not designed to work well with a GFCI, which could lead to nuisance trips.
    – Tester101
    Commented Oct 26, 2014 at 4:15
  • I agree. My main point of the answer was to point out that it was technically feasible to install the GFCIs.
    – Michael Karas
    Commented Oct 26, 2014 at 4:47

If it ain't broke, don't fix it.

The pump is likely plugged into a single receptacle on a dedicated circuit, because there used to be an exception in the code that allowed a setup like that to avoid GFCI protection. It's possible that the pump will not play well with the GFCI, and then you'll be up shits creek (literally).

It's quite possible that the other pump was originally installed this way too, but then somebody needed an additional receptacle in that area. This person likely didn't understand what was going on, and swapped out the single receptacle for a duplex. Or all this equipment was installed before code required GFCI protection.

Newer pumps should be designed to work with GFCI protection. If you ever update the pump, you should be able to switch to a GFCI then. For now, I'd leave it as is.

If you're worried about flooding due to a power outage, you could install a backup water powered sump. Or better yet, get a generator.

  • They may have been using the alarm system exception (for the sump-pump+alarm dual outlet), since it is sharing with the alarm system.
    – Ecnerwal
    Commented Oct 26, 2014 at 14:29
  • @Ecnerwal A sump pump + alarm system exception? I must have missed that one. Do you know the code section for that?
    – Tester101
    Commented Oct 26, 2014 at 15:51
  • 2008 210.8 A 4 for alarm systems. Those are STILL excepted from GFCI protection, while sump pumps were de-excepted in 2008. If the sump pump and alarm system were both plugged into a duplex receptacle, it would not be leaving an accessible outlet and nether required GFCI protection prior to the adoption of 2008 Code, which required it for the sump pump, but not the alarm.
    – Ecnerwal
    Commented Oct 26, 2014 at 23:45
  • @Ecnerwal I think you're referring to the exception to 210.8 (A)(5), which says: "Exception to (5): A receptacle supplying only a permanently installed fire alarm or burglar alarm system shall not be required to have ground-fault circuit-interrupter protection." Notice that it says "A receptacle supplying only". Which means if the sump is also plugged in, it no longer meets the exception. The Sump pump exception was similar, in that the pump had to be the only thing connected to the circuit.
    – Tester101
    Commented Oct 26, 2014 at 23:54
  • Thanks, everyone, for your insights. I think you've all convinced me to leave everything alone. For what it's worth, it looks like I'm going to have to keep the sump and the alarm together, since the power supply for the alarm magically pops out of the drywall right next to the outlet. I'm in a bind for plugging in this battery backup. The only other available outlet in the room is a dual non-GCFI outlet that also has a switch for the furnace, with only 1 receptacle in use for the humidifier. Any problems with plugging the battery backup into the other slot?
    – mike a.
    Commented Oct 27, 2014 at 6:10

GFCI is not required for dedicated circuits when a nuisance trip would be unfortunate - usages such as freezers or sump pumps. So, I would not put a GFCI on those circuits.

They must, however, not have outlets that other appliances could be plugged into. The ejector pump is okay, but the sump pump does not conform to code, as it has another outlet.

Two separate circuits would be needed if the ejector and sump pumps took more power than could be supplied by one circuit.

You current setup would be fine going forward for the sump pump + battery backup (1 duplex non-gfci outlet), and the ejector pump (1 single non-gfci outlet). You should move the alarm to a GFCI outlet.

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    Much though I'd like to agree, this went poof with the 2008 edition of the NEC, as I understand it.
    – Ecnerwal
    Commented Oct 26, 2014 at 3:32

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