I have a large backyard pond. To run the waterfalls, filters, and circulate the water, there is one 30-watt septic air pump, plus three 120-volt, 300-watt water pumps. The pumps move about 15,000 gallons each hour.

All of these have 100-ft cables, which I plug into an outlet that just has two plugs. I have two 1-ft extension cable "splitters" allowing me to plug in the four devices to the one outlet.

I want to make changes to it so it is a more safe setup, I am considering two changes:

  • Replace the two-outlet box with a four-outlet box so I no longer need the two splitter cables.
  • Get an out-let box that has a rain cover (see picture) with a spot for cables to run out the bottom.

I'm not very familiar with electricity in homes. Are there any additional changes that should be made to make sure this is a good setup?

NOTE: The outlet where these are plugged into is only 3 feet away from the fuse box (which is on the outside of the house).

enter image description here

  • How many 100’ cords are you running? Commented Dec 30, 2022 at 18:48
  • Three devices have 100' cords. The septic pump is maybe a 20' cord and instead pumps air down a 100' air hose.
    – Village
    Commented Dec 30, 2022 at 19:20
  • 1
    This is the stuff of another question, but I'd be concerned about voltage drop on such a long run. (Unless all of your extension cords are awg12.) If we believe the internet, voltage drop of >8% is bad for long term durability of pump motors. Commented Dec 30, 2022 at 23:46
  • I'm not sure if I understand your meaning, the pumps are sold with that length of cord built-in, I'm not using extension cords.
    – Village
    Commented Dec 31, 2022 at 4:25
  • Oh, in that case, ignore me. The manufacturers will have thought through any issues. The advice below is good. Commented Dec 31, 2022 at 14:23

3 Answers 3


This may be a bit of overkill, but be beneficial down the road if anything is added. I would add a new circuit to the breaker box. 20amp with #12 wire out to a quad outlet with the waterproof cover. A GFCI outlet feeding the second outlet so everything is protected.


You're on the right track with expanding the box to a 2-gang and installing 2 duplex outlets (for 4 outlets total). That will eliminate the unnecessary connection points at the splitters.

Your second idea of installing the in-use cover is also perfect.

The only other thing I would do is make sure that you have GFCI protection for the whole setup. That can be accomplished by installing a GFCI outlet in the first gang and daisy-chaining the second off the "load" terminals of the first, or simply installing a GFCI breaker in the panel. Your choice.


You've definitely got the right idea with getting rid of the splitters. Make sure the outlet weatherproof cover you get allows you to snap it closed with the plugs plugged in. Some covers open and don't close completely when you're using the outlets. See below photo from Lowe's. The photo also shows a GFCI outlet that also protect the outlet next to it.

enter image description here

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