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Using a 240v generator with four prong plug on well pump using 3 wires

Using a 240v generator with four prong plug on well pump using 3 wires

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  #1  
Old 03-15-18, 05:11 AM
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Using a 240v generator with four prong plug on well pump using 3 wires

I want to use a 240v generator occasionally during a power outage but the 240v wire coming from the breakerbox (from 2 poles 20amp) is 3 wire (black,white,ground) and the Nema L14-30 4 prong uses 4 wires. I want to add an outlet to the wire coming from the breaker box and a plug going to the well pump. how do i wire this in as i need 3 wires but only 3 exists?

dave240vphobic
 
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  #2  
Old 03-15-18, 05:38 AM
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Hi,where is that male 4 wire plug coming from? Best to plug that pump directly into the generator,that setup in the pic has the potential to back feed the utility.
Geo
 
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Old 03-15-18, 07:33 AM
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You can plug the pump safely only by plugging directly into the generator. Any other way requires a transfer switch or interlock to prevent deadly feeding of electric to the power company grid..

If plugged directly into the generator only the hots and ground on the plug are connected to the pump. neutral prong is not connected.
 

Last edited by ray2047; 03-15-18 at 11:10 AM.
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Old 03-15-18, 10:11 AM
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The plug and outlet is not connected to anything. These are the things I want to add but they both have 4 wires and the existing is all three wire.
 
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Old 03-15-18, 10:20 AM
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So are you saying that I put the white wire going to the pump on one hot prong and black on the other hot prong and leave silver open and ground on ground?
 
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Old 03-15-18, 11:17 AM
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Yes, if the pump is 240 volts only. Actually the cord the female cap on the cord and plug on the pump could have been 3-wire. Only the plug for the generator needed to be 4-wire.
 
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Old 03-15-18, 12:50 PM
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But I do not think the white and the black are both hot. itís coming from the breaker box and isnít the black hot and the white neutral When I put a voltmeter between the black and the white it shows 240
 
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Old 03-15-18, 02:21 PM
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A two wire cable uses both the black and white as hots.The

A cord cap is not listed for use on NM cable.
 
 

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