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I'm helping my folks install battery-operated sump pumps in three window wells to deal with a persistent flooding problem. We're running a GFCI-protected circuit from a nearby sub-panel to each location for the battery tenders.

Is it acceptable to install wall-mounted outlets (with full plastic conduit and weather-resistant covers) below grade in egress window wells?

  • That seems kind of sketchy to me. Weather-resistant covers are not water proof (especially not if something is plugged in), and if the well fills with water due to a heavy rainstorm, then you'll certainly have a shocking problem. Can't you just put the outlets at normal height up the wall, or hard-wire them? – user48010 Apr 26 '17 at 18:52
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    I have installed outlets outside below grade in the past (basement entry's) but an area that is prone to flooding ? What happens if the pump fails? I understand the GFCI will be at the panel but this one could be sketchy if the outlet is not above the high water line. Great question. – Ed Beal Apr 26 '17 at 18:57
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    Anything that is not designed to be submerged will be a problem if it can potentially get under water. Mount the weather-resistant outlets above ground level. – fixer1234 Apr 26 '17 at 18:58
  • @EdBeal That's the quesiton... where's the high water mark? There's a slope to the entire area. Low point on the adjacent grade for each window? Top of the well wall? – isherwood Apr 26 '17 at 19:23
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    The electrical datum for docks has to be 2' above the high water. article 682 took me quite a while to remember where I had found that in the past. If nothing else I would use that as it is an artificial body of water ... wadda you think? – Ed Beal Apr 26 '17 at 21:48
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You wish to install a weatherproof outlet below-grade in a basement egress window well that is prone to flooding. Apply NEC Article 682 which instructs you to determine the electrical datum and install any non-submersible devices at least 2 ft above the datum plane.

For example, suppose a pump fails with the outlet energized. In that case your flood line could reach either the top of the egress window or the top of the egress window well. The electrical datum would be 2 ft above that line and your weatherproof outlet needs to be installed above this plane.

If the sump pump is submersible you will need to install a local disconnect This will need to be no more than 30" from the pump so probably a switch within the weatherproof box.

Consider whether the outlet and pump will impede egress from the basement in an emergency. Can the window be opened from inside? If the pump blocks a portion of the window or well reduce the effective size accordingly and then determine whether the window and well continue to meet local standards for egress. Not every window well must qualify as an egress window but there will need to be at least one that does. See section R310 of the International Residential Code and/or any applicable local codes.

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In passing: When things go wrong they go very wrong.

Consider the following scenario:

Window well pump ingests a bundle of leaves, and clogs. Water rises. Water gets above the lower plug. GFCI trips. Water continues to rise. Now it covers the live screws of the GFCI Depending how clean the water is you may not have enough current to trip the breaker. Now Mr. Homeowner is trying to clear a clogged pump in a thunderstorm with live power to the water and surrounding metal window well.

This doesn't have a good feeling.

IF you (or someone reading this) does something like this:

Ideally:

  • Follow code and put the plug 2 feet above the max water level. Two feet is an arbitrary number. If you only have 18" room to work with, make it so. But I don't have to deal with YOUR inspector.
  • Use a rainproof outlet -- not the flip caps that keep the outlet dry when closed, but ones that keep it dry in use. Usually a hinged hood with wires coming from below.
  • GFCI inline BEFORE the outlet so that the entire box is cut off when it trips. (Easy: Put an outlet in the room.)

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