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Split 240V to two 120V GFCI (two-hots and a ground on a two-pole 40A breaker)

Split 240V to two 120V GFCI (two-hots and a ground on a two-pole 40A breaker)

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  #1  
Old 08-18-17, 03:15 PM
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Split 240V to two 120V GFCI (two-hots and a ground on a two-pole 40A breaker)

I just bought a house on a well that requires a water softener and filter. The well pump is hardwired to a three wire (white, black, and bare) 240V circuit in a box by the well. The circuit breaker in the house is a two-pole 40A (two connected 20A).

My softener and filter meters each have a power brick with 120V 15W input/ 24V 400mA output.

I'd like to add a dual 120V GFCI in-use outlet to the post to plug in the softener and filter power supply bricks

Is it possible?

I have a vented water-proof box for the power supply bricks to sit in.

Thanks in advance!

Warren
 
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Old 08-18-17, 03:21 PM
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The current circuit does not have the neutral you need for any 120 volt circuits .

The two pole 20 is still 20 amps. You do not add both side together .
 
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Old 08-18-17, 03:22 PM
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You need a 4 wire to split the 240 to two 120. You are missing the required neutral wire.
 
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Old 08-18-17, 03:30 PM
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Thanks guys.

How about if I just replace the whole box with a new box that has circuit breakers (such as an RV box)? Could I then add a 240V receptacle and a couple 110V receptacles?

https://www.houzz.com/photos/5355446...es-and-outlets

Is it doable without the Green wire?
 
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Old 08-18-17, 04:09 PM
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How about if I just replace the whole box with a new box that has circuit breakers (such as an RV box)? Could I then add a 240V receptacle and a couple 110V receptacles?
As we keep saying you do not have a neutral. 120 volts (not 110v) is derived from one hot and a neutral.
 
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Old 08-18-17, 04:23 PM
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Thanks. I understand there isn't a neutral. What did we do before 4-wire when we needed 120V and all we had was 240V?

http://www.irv2.com/attachments/phot...63ca338515.jpg

Is this viable with my needs in mind?
 
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Old 08-18-17, 04:32 PM
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Even if you switched the cable into the panel you do not have the neutrsl. You have two hots and a ground. You need a new circuit for the 120 circuit.
 
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Old 08-18-17, 04:48 PM
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What did we do before 4-wire when we needed 120V and all we had was 240V? Is this viable with my needs in mind?
No. Before 4 wire cables they were ungrounded circuits. Ungrounded circuits are not allowed due to the lack of the ground wire for safety. You can have one 120 volt circuit or one 240 volt circuit. Not both. You need to run a new cable/circuit to do what you want.
 
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Old 08-18-17, 04:57 PM
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I've done some reading on the pump pressure switch and it will work with either 120 or 240...

The solution may be as simple as convert that 240 line into a 120 line at the panel, by replacing the two-pole breaker with a single 20A breaker then use the three wires as hot, neutral, and ground.

Does that work?
 
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Old 08-18-17, 05:14 PM
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Does that work?
No. It is not the switch that needs 240 volts, it is the pump motor.
 
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Old 08-18-17, 05:16 PM
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Ahh. Thanks. I guess I'm back to digging in a new wire!
 
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Old 08-18-17, 05:49 PM
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guess I'm back to digging in a new wire!
Do you have conduit with individual conductors? If so you may be able to pull in a wire but not if you have cable. If cable it will need to abandoned if the pump is inside a pump house and new cable installed for a subpanel.
 
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Old 08-19-17, 12:41 AM
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Another way it could be done is to install a relatively small 240 volt to 120 volt step-down transformer at the pump house. You would need to use the appropriate fuses (two) on the transformer primary and a single fuse on the transformer secondary with the unfused secondary lead also attached to a grounding electrode. This would certainly be easier and maybe a bit less expensive than replacing the entire cable run.
 
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Old 04-23-19, 07:54 PM
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Maybe done by now, but... The power bricks are likely outputting 24v AC (at least my water softener powerbrick does). It is just a transformer from 120v to 24v. You could use a 240v to 24v transformer to supply power to the softener and filter at the post. It wouldn't be GFCI, but you could put a GFCI 240v breaker in the box for whole pump circuit if that's a concern.
 
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Old 04-23-19, 09:35 PM
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Maybe done by now
It's a 20 month old question, please assume in the future that they are done at that point.
 
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