How to wire a 2 pole switch .....

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  #1  
Old 06-17-19, 01:37 PM
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How to wire a 2 pole switch .....

Okay - total newbie here. Let me first describe my setup....

1. I have a cottage with a well pump that is 240v (15amp) so from the breaker panel i have a 2-pole 15 amp breaker (white wire in 1 pole and black wire in the other)
2. This 14/2 wire runs to a 2 pole switch. The white and black wire from the breaker go to the top 2 screws in the switch and the 2 wires from the well pump go to the bottom 2 screws. Simple enough
3. The pump switch is in the basement and I wanted to be able to turn off the pump with a switch at the front door whenever i leave the cottage without having to go to the basement (yes, call me lazy but also if friends are using the cottage I can just tell them to turn on the switch at the front door without them having to hunt it down in the mechanical room)
4. I had during construction run a 14/3 wire from front door back to the pump switch for this purpose - however, i did not realize at the time it was going to be a 240v pump.

So question is, is there a way i can wire this so i can turn off the pump from the front door with the wiring i currently have in place. Had I had 4 wires at the front door I don't think it would not be a problem but having only 3 I'm not sure I can accomplish what I want...

Any insight?

Thx
Ron
 
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Old 06-17-19, 01:55 PM
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Are you proposing moving the switch or adding another? If the latter, you are now in what's known as a three way switch and different equipment needs to be purchased.
 
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Old 06-17-19, 02:25 PM
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You could use the cable you have and only turn off one of the hot wires. This would turn off the pump but leave one hot wire hot.
The switch at the pump would turn off both hots if you ever needed to work on the pump.
 
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Old 06-17-19, 02:37 PM
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Add a 120 volt 2-pole relay in the basement controlled by the switch at the door. The relay contacts should be wired in series with the 2-pole switch (i.e. 240 v power from breaker to switch, from switch to relay contacts, from relay contacts to pump.

Connect switch (black wire) at front door to one leg of 240 (on the load side of the 2 pole switch) and red wire from door switch back to relay coil. Connect relay coil to neutral wire to complete the circuit.

Both front door switch and basement switch have to be ON for pump to run. (Not a 3-way switch arrangement.)

If you run the neutral (white) wire to front door switch you can include a pilot light there that will turn on when power is on (both switches ON). If either switch is off the light will be off and there will be no power to the pump.

I have a similar setup in my vacation home but I included enough wiring for a second pilot light that shows when the pump is running in addition to the "Power On" light. You don't have enough wires to do that.

What joed said will also work but may cause some safety concerns. (actually that is how mine is wired from 30 years ago. Don't know if current code allows switching only one leg.
 
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Old 06-17-19, 06:37 PM
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As long as the service switch at the pump disconnects both legs....... switching one hot conductor before that point should be ok.
 
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Old 06-18-19, 04:54 AM
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Relay not needed

Good morning.

PJ is right. However, now that I have slept on it, here is another suggestion....

You could wire the door switch in series with the pressure switch (presumably 120 volts via the pump controller.)

If you wire the switch ahead of the pressure switch, you can include a pilot light at the switch to indicate "Power On" by connecting it to the load side of the switch and the neutral. (If you also want a "Pump Running" indicator you could use a current sensor with a low voltage pilot light. More info here https://www.instructables.com/commun...or-light-syst/. I thought Amazon had one but I cannot find it now. Here is one that shows amps in numbers https://www.amazon.com/YUNAWU-Digita...ateway&sr=8-49) that would work.

If you wire the switch after the pressure switch a pilot light connected to the load side of the door switch and the neutral will indicate "Pump Running" but you would have no indication if the power was turned off in the basement.

Electrical engineer gets inspiration while sleeping and provides complicated answer to simple question. Sorry.
 
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Old 06-18-19, 09:11 AM
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Thanks guys for the responses. Really appreciate it. So if I understand John (2john02458) and PJ suggestion I would take one leg from the panel that is connected to a 15amp breaker and run it through the switch at the front door and then simply connect it at the pump switch....effectively allowing me to break 1 of the 15amp circuits. The other wire (coming from the 2nd 15 amp pole at the panel) remains as it does today. I just wasn't sure if i could leave 1 hot wire going into the switch ? I guess i don't understand the circuitry of a 240v system well enough. I guess if i break the circuit of the pair coming from the breaker panel I'm essentially breaking the entire circuit - that is, both feeds must be "live" going to the pump in order for it to work....do i have that right? And the switch at the front door can just be a regular switch (similar to what is used for a light)....and the switch could have an indicator light if i choose....

I've shared a link here with a crude diagram of what i think you are suggesting .

https://1drv.ms/u/s!Aq0Wa3I05uFshJVV...rmVHg?e=ccnMVD

Thx
Ron

I have attached a crude wiring diagram.....let me know if i have wiring correct
 
  #8  
Old 06-18-19, 10:30 AM
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Your diagram is correct. Technically you should use a heavy duty (20 amp) or motor rated switch.

Remember that the breaker (not just the pump switch) needs to be shut off if work is to be done on the door switch now or in the future. Wiring the door switch on the load side of the pump switch might be a safer alternative.

A note in the box or on the back of the cover plate noting that it is part of a 240 volt circuit is wise.

By code both breakers for the 240 volt circuit must operate together. If they are single pole breakers they must be adjacent and have their handles tied together to operate simultaneously. There are usually holes in breaker handles to do that with a wire or bolt if a handle tie is not used.
 
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Old 06-18-19, 12:37 PM
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Another way is to have a contactor (aka motor starter) do the switching of the large pump motor current, and so the switch by the door only has to handle the small current of the internal coil that actuates the contactor. This is similar to what 2john02458 mentioned with a relay except that the contactor directly connects the pump motor load to the line voltage, instead of going through relay contacts and pump switch contacts that are connected in series. Contactors are specifically designed for motor starting and so they can handle your application. A contactor would also avoid the additional voltage drop from routing the pump current to and from the front door switch.

The link below is a schematic of a contactor being controlled by a pump switch. For your situation you would wire the front door switch in series with the coil on the contactor, so that it would be disabled when the switch was turned off.

https://electricalcircuitdiagram.clu...sting-afif.jpg
Of course, there would be no 3-wire control box if you have a 2-wire pump.

This a a contactor that might be used:
https://motorsandcontrol.com/weg-ele...motor-starter/
 
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Old 06-19-19, 09:38 AM
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I just re-read your first post and noticed that you only have 14/2 from the panel to the pump switch. That white wire is carrying one side of the 240 volts (L2) and should be taped some other color (not white or green) where visible at the panel and at the switch. You have no neutral only 240 volts from L1 to L2. In that case there is no 120 volts available for any of the suggestions I made requiring that voltage. If you use pilot lights they will have to be rated for 240 volts. The ones I used were neons with that voltage rating.
 
  #11  
Old 06-19-19, 10:28 AM
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Thanks again for the replies. I like the idea of using a contactor. I'm assuming i would need a 2 pole 240v 15AMP+ contactor - something like this => https://www.amazon.ca/CONTACTOR-Pole...gateway&sr=8-7

I'm also assuming I don't need to have a pressure switch at the door but merely a heavy duty 120v 20AMP switch.

If i follow the wiring diagram properly I'd essentially be running both L1 & L2 into the contactor. I'd then carry a line off from Line 1 up to the 120v 20Amp switch at the front door (say on the white wire) and loop back to the contactor from the switch (say with the black wire)...so essentially 3 wires going into the contactor (L1, L2 and line from the switch) and then 2 wires coming out (both the L1, L2 to the well pump).

Did I make any sense?

Thx
Ron
 
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Old 06-19-19, 02:14 PM
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You do not need a contactor. Since you only have 240 volts to work with and you are running that to the door location anyway you just need a switch there as you showed in your diagram in Post #7.

The suggestion to use a contactor was only to avoid running the 240 v to the door switch (if 120 v was available--and it is not) or to avoid voltage drop. Using a 240 volt contactor requires running 240 volts to the door switch but that performs the same function at more cost and complexity than just putting a switch there. Keep it simple.

In any case whenever a white wire is used in a power circuit it must be taped or painted a color other than white or green to indicate that it is not a neutral or ground. (There may be an exception for switch loops on 120v lighting circuits that allows white to be used unmarked for line power to the switch as long as the connection at the fixture is a non-white and a white wire.) Marking the white wire is especially important when using 240V due to the lethal possibilities. If you have a 3 wire cable going to the switch location you should use the black and red wires for switching power and cap the white at both ends.

If voltage drop is a concern and you are using a contactor to avoid that, then your description of the wiring will work (recognizing that the return wire from the switch is to be connected to the coil terminal and the other coil terminal is connected to L2 at the contactor.) There will be 6 wires to the contactor--two from the pump switch (L1, L2), two to the door switch (L1, L1 switched to the coil) and two to the pump. The L2 connection to the coil will be at the contactor.

Also the contactor should be mounted in a suitable enclosure. The 240 volt connections and terminals are dangerous and must not be exposed to accidental contact.
 
  #13  
Old 06-20-19, 09:46 AM
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Thanks John - very clear explanation. Appreciate it. One last question (ok, maybe 2). Since I have a 3-way wire running from front door to mechanical room can I just treat this line as a normal 3 way and have a 3-way switch at the door and a 3-way switch at the pump? (see link below to my new diagram) 2nd question. I'd like to have a toggle pilot light switch (see example below from amazon) so i know when pump (or more accurately L1) is on. Normally, i think these pilot light switches require a connection to neutral so the pilot light can be lit up. At the front door i have access to a neutral from another run....but in the mechanical room i do not. I'm assuming i can just run another wire from the neutral in the panel to the toggle switch? Or should i not be doing this?

Link to new 3 way diagram
https://1drv.ms/u/s!Aq0Wa3I05uFshJVu...gVfFA?e=bxlyze (new diagram with 3 way switch)

Link to 3 way toggle switch with pilot light
3 way toggle switch with pilot https://www.amazon.ca/gp/product/B00...K6Y9EEQB&psc=1

Thanks again for all your help
Ron
 
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Old 06-20-19, 10:58 AM
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Technically the 3-way arrangement will work--not sure it is allowed by code because it is a 240V power circuit (not lighting).

That switch with pilot light is only rated for 120V. You cannot use it to switch 240V. Also you cannot take a neutral connection from another circuit. The neutral connection must be part of the same circuit and must run with the line conductors. You risk a safety hazard by possible introducing 240V into the circuit you "borrow" the neutral from and you risk a fire hazard by running the neutral separately from the line conductors.

Pilot lights for 240V are available and can be connected as I described earlier for a single switch. With a 3-way switch arrangement you would need a fourth wire for the L2 connection to the pilot light.
 
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Old 06-20-19, 01:16 PM
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Thanks John. I thought i understood what was going on but maybe not. I thought because I'm only bringing 1 line from the panel (L1) through the switch at the front door, the front door switch would only be carrying 120V. That is, the potential difference between this and neutral would be 120v - just like it would with any other wire for lighting. It would only be 240V at the 2nd switch in the mechanical room when L2 (on a different phase) is introduced (see my diagram). Furthermore, if all white wires are connected to the same bar in the panel breaker, then why would it matter if i run a second white wire to the switch that contains just L1? Are all white wires not the same? I know I'm not understanding something just don't know what I'm missing. Thanks for guiding me through this....hope I'm not bothering you too much!

Thx
Ron
 
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Old 06-20-19, 02:04 PM
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Voltage is relative--that is it is a measurement of electric potential from one point to another. In a 120/240 volt system, voltage from L1 to N is 120, from L2 to N is 120, L1 to L2 is 240. Ideally any L to ground should be the same as L to N but can be anything from 120 to 240 depending on specific conditions. N to ground should be 0 but again under certain conditions could be as high as 240V.

But a neutral also carries return current (amps) to the system. In a balanced branch load the current on L1 and L2 balance out and there is no current on the neutral (0 amps) in a 3 wire 120/240 volt circuit. But most loads are not balanced and the neutral carries some current back to the panel where it balances out against loads on other circuits. (In two wire 240V circuits L1 and L2 are by definition balanced as there is no neutral. I won't get into the theory but this occurs because L1 and L2 are different phases of the larger 3-phase system that feeds the network.)

The neutral is grounded at the panel to provide a single point of reference for all circuits in the panel. Grounding a neutral downstream of the panel is against code as it can interfere with the proper operation of a system such as allowing a separate return path to the network transformer bypassing the panel.

Overload protection of the neutral wire is provided by the branch circuit breaker assuming that the current the neutral carries will not be larger than the current on the L wire that it is paired with. If you introduce current from another circuit (i.e another breaker on the same phase sharing the neutral--think two breakers connected to the L1 bus at the panel) the total could exceed the capacity of the neutral, overheat, and cause a fire.

I hope this background helps you understand the suggestions that have been made. Keep it simple. Be safe.
 
  #17  
Old 06-20-19, 06:49 PM
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Thanks John - very helpful. I like the keep it simple and safe. So can I (or is there a way to) use just 1 switch (120v single pole) at the front door that has a pilot light? I ask because i think the switch that has a pilot light has to be connected to a neutral but in my case i don't have a neutral to connect to). Referring back to my original diagram. https://1drv.ms/u/s!Aq0Wa3I05uFshJVV...rmVHg?e=ccnMVD

Thx
Ron
 
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Old 06-20-19, 07:00 PM
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switch that has a pilot light has to be connected to a neutral
Since you have no neutral in that circuit from the panel 120 volts is not available. See Post #10.
 
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