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Is there a way to trip a breaker, or otherwise kill the connection to an appliance during a power outage that doesn't automatically turn back on when power is restored?

Background: home in the north that runs a well pump that I may not be at for a week at a time. Heater is on all winter (set to 50 deg), but if the power goes out, the temps will drop well below freezing. The water in the pipes will cause an issue when the power kicks back on and warms up the house if a pipe burst. An "issue" will turn into a complete disaster if the well pump turns back on and feeds the pipes until I show up to turn it off. So, I'd like the well pump's power to be automatically killed during a power outage and only turn it on manually when I can get to the house to inspect, even if the power to the main has been restored.

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    Someone may have a solution (I can think of a solution but it is a bit of a Rube Goldberg device...), but why not simply shut off the well pump on your way out? If nobody's there, you don't need any water. – manassehkatz Aug 6 at 2:48
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    Do you want this to be a completely automatic solution, or is throwing a switch when you leave the place acceptable? Also, can you provide schematics of the pump control box? – ThreePhaseEel Aug 6 at 3:38
  • @manassehkatz -- that's not something that one can guarantee to be true any longer. – ThreePhaseEel Aug 6 at 3:52
  • @manassehkatz - frankly, that's probably the best way to go. I'm new to homeownership in cold regions and have heard that maintaining a slight trickle in at-risk faucets can prevent freezing, thus my desire to keep the main flowing. – elPastor Aug 6 at 11:15
  • Coincidentally, I've recently seen a lot of ads for Moen's "Flo" (meetflo.com). Looks like it takes a slightly different approach to the same issue - when the power is on and it detects a leak, it will shut the main valve. If the power is off, the well pump won't be working anyway. It is an AC unit, not battery powered. – elPastor Aug 12 at 20:18
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If your HVAC situation permits it...

The ability to have a source of heat that works during a power outage is a massive asset, especially if power outages are a serious concern (as they typically are on the long overhead feeds found in rural areas). Either a wall furnace (Empire-style) or a gas fireplace can be used; either way, you'll want a sealed combustion version that draws its combustion air from a dedicated outdoor source to avoid any potential issues with backdrafting, CO, and the likes.

Dealing with the original problem, though

However, not all folk are in a position to have heat that works during a power outage, either due to a lack of fuel (gas) service to their location, or due to limitations of their existing HVAC systems. Given this and a couple of assumptions about your well pump, namely that it is a single-phase, 230V unit of 2HP or less and uses a 2-wire start system with a direct-operating pressure switch control, we can solve this problem quite simply and relatively cheaply (under $100) with a few fairly basic industrial-control type parts:

  • A 230VAC, 20A, DPDT enclosed relay, namely the RIB02P (this is basically a lightswitch that's rigged to an electromagnet so that it can be controlled by an electrical signal)
  • A 22mm, 1NO/1NC, momentary-contact illuminated pushbutton with a 230VAC illuminator, in a color of your choice
  • And a single-hole 22mm control station enclosure (metal or plastic, rated to go where you're putting this at) with a couple of 1/2" KOs in it.

This all gets wired up as follows, or as per the diagram below (which omits grounds for clarity's sake), once you attach the box to a suitable wall surface (note that most control station enclosures don't support being flush-mounted inside a wall in a finished space, as they're designed for industrial use), mount the relay to one of the 1/2" KOs using a locknut, fit the switch through the hole in the front of the box, and feed the incoming and outgoing cables through the remaining knockout(s) using cable clamps:

  • One of the incoming hot wires connects to a normally open (NO) terminal on the pushbutton along with one of the common (COM) wires (yellow or purple) from the relay
  • The other incoming hot wire connects to a coil (brown/white) wire and the other COM wire from the relay
  • The NC wires (blue and grey) from the relay connect to the lamp terminals on the illuminated pushbutton
  • The NO wire (orange or brown) from the relay that corresponds to the COM wire you picked to connect to the incoming hot going to the pushbutton connects to a normally closed (NC) terminal on the pushbutton, along with one of the wires going onward to the pressure switch and well pump
  • The other wire going to the well pump/pressure switch connects to the other NO wire from the relay
  • The other coil wire from the relay connects to the remaining NO terminal on the pushbutton, which then jumps to the remaining NC terminal on the pushbutton with a short length of insulated wire
  • Last but not least, the incoming and outgoing grounds connect to each other (and to a ground pigtail, if the box you used is metal)

wiring diagram for the above, grounds not shown

This all forms what is known as a stick circuit, using the relay to provide a memory of power failure in the following fashion:

  1. We start with the power off. The pushbutton and relay contacts are all in their Normally Closed positions, which means that the relay coil has one side connected to the power that's being switched by the relay's Normally Open contacts, and the incoming power is connected to the indicator, not to the rest of the circuit.
  2. When we apply power to the circuit, the indicator lights, as it's connected to the incoming hot through the relay's Normally Closed contacts. Nothing else happens, though, since the relay's coil is not powered.
  3. Pushing the button switches the switched side of the relay coil from being connected to a Normally Open contact of the relay (connected through the button's Normally Closed contact) to being powered directly from the line through the button's Normally Closed contact.
  4. This pulls in the relay, energizing the pressure switch and pump motor through both sets of Normally Open contacts on the relay while de-energizing the Normally Closed contacts, which causes the indicator to go out. (Why both sets? It's because both sides are "hot", and the appropriate motor rating for the power relay used requires all poles to be switched.)
  5. Releasing the button at this point connects the relay coil to the now-powered Normally Open side of its own contacts through the button's Normally Closed contact, thus holding, or "sticking", the relay in its energized position.
  6. With the button released and the relay energized, the pump can now run normally, as if our circuit wasn't there, while our circuit is ready to detect the next power failure.
  7. Turning the power to all this back off de-energizes the relay, which causes its contacts to return to their Normally Closed state, bringing us back to the state we were in at the beginning of this description.
  • First off - thanks a million for all of the information and detail. But being new to this branch of StackExchange, I'm realizing most of these solutions are way over my head. Either way, food for thought and worth investigating. – elPastor Aug 7 at 10:30
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This can be handled with a simple motor start station rated adequately to handle the load of the well pump. Additionally, you will need a momentary manual start switch. Feed the control circuit through momentary start switch off the line side of the contactor. Feed a holding circuit off the load side of the contactor. Then with a standard manual disconnect in-line, feed the control circuit a second time from the line side of the contactor.

Whenever you leave the house for an extended period simply open the standard start switch. Under these conditions the pump cannot start automatically. When you are living on site the manual switch will be left in the closed position so that your pump will cycle automatically as necessary.

  • Hi Paul, thanks, and you may be spot on, but you're gonna have to dumb it down for me. I'm not familiar with motor start stations or momentary manual start switches. Guess I could just Google them, but if you can provide a dummies version, I'd appreciate it. – elPastor Aug 6 at 11:13
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Simpler than that...

Use a rundown timer on the water pump

12 hours after you set it, it automatically shuts off, whether you are present or not. It's a nuisance while you're there, but can't be forgotten.

Use a furnace that doesn't use electricity

That would be an "Empire style" floor or wall furnace. Ours does fine service during outages.

  • Really like the "empire style" furnace solution... now off to find out what the hell an empire style furnace is. Thank you. – elPastor Aug 6 at 14:07
  • @elPastor an "Empire" furnace is a gas-fired wall furnace that uses a standing pilot for ignition, an integral or millivolt thermostat, and convection for air circulation into the room, so it doesn't need electricity at all to run – ThreePhaseEel Aug 7 at 1:04
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I'd like the well pump's power to be automatically killed during a power outage and only turn it on manually when I can get to the house to inspect,

I'd use a thermostat inside the home, set to a few degrees above freezing. When temperature is too low, it shuts down power to the pump. You need a thermostat for air conditioning, not for heating, as contacts need to be closed when temperature is hot, not when it is cold.

This is not exactly what you asked for, but it has an extra feature: it also protects against a failure of the heater, or a blown fuse or circuit breaker on the heater, or any other scenario where you'd still have power but the heater doesn't work.

  • The issue with this approach is that it won't lock the pump out after a potential freeze-up without extra help – ThreePhaseEel Aug 8 at 1:41
  • @ThreePhaseEel hmm, that's true... it would need either a latching relay after it, or it would need to be a "thermal trip", I have no idea how that's called in English but a circuit breaker that trips in freezing temperatures and has to be reset manually must exist, after all OP isn't the first guy to want to protect pipes from freezing... – peufeu Aug 8 at 12:16
  • Actually, you can do it with an ordinary relay (not a latching relay) but you'll need to wire it as a stick relay circuit...the bigger issue is trying to run pump current through a typical fan thermostat, really, as that's what you have to do if you're not using contactor control... – ThreePhaseEel Aug 9 at 1:49
  • There's also the issue that this would lock the pump out "in the instant" if indoor temperatures threaten pipe freezing, which could paradoxically lead to a freezeup due to loss of flow from a faucet kept at a trickle to avoid it freezing up. – ThreePhaseEel Aug 9 at 2:05

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