220 plug type, 3 prong vs. 4 prong ?

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Old 08-11-16, 10:32 PM
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220 plug type, 3 prong vs. 4 prong ?

I was trying to assist a friend with a 220v water pump at a lakeside campsite.
The plug on the pump is a 220 volt 3 prong plug, but the receptacle on the generator which will be used to power it is 4 prong.
What are the differences between the two, and is there an adaptor which can be used? The 4 prong configuration implies 4 wires in use, so how can that be integrated with the 3 prong setup?

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Old 08-11-16, 10:48 PM
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First of all, in North America the specified voltage is 240, not 220 and it has been that way for at least fifty years. In fact, if you look closely at the plug you will likely see it is rated at 250 volts.

The three prongs are for the two "hot" leads and the third is for the equipment grounding conductor. In a four-prong arrangement you have two "hot" leads, a "neutral" lead and the equipment grounding conductor. This supplies BOTH 240 volts via the "X" and "Y" connections PLUS/OR two, 120 volts circuits using the neutral lead with the X and Y connections.

You can make your own adapter by using a plug matching the generator receptacle and a "connector" body matching the pump plug. Wire from the X terminal on one to the same on the other. Follow suit with the Y terminals. Wire the G (equipment grounding) terminals together and ignore the N terminal on the four-prong plug.
 
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Old 08-11-16, 10:57 PM
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Your pump requires two hot wires and a ground.
Your generator supplies two hot wires, a neutral and a ground.
Technically the neutral and ground is tied together inside the generator.

Not sure if there are adapters available but it may be easier to put a new plug on.
Otherwise you'd need to buy a 4 prong plug and 3 slot female cap.

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Old 08-12-16, 08:40 AM
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The unused neutral terminal on the 4 prong plug/socket is marked as "W".
 
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Old 08-14-16, 09:24 AM
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thanks guys

I have a new 4 prong plug which will be replacing the existing 3 prong plug on the pump wire. while I do not have the pump in front of me as I write this I will assume the old wire with the 3 prong plug has 3 wires, two hot and a ground.
so I will be putting the two existing hots into the same X and Y slots on the new 4 prong plug, putting the existing ground into the G slot on the new 4 prong plug and ignoring the W on the new 4 prong plug.

is the "coding" X,Y,G,W an industry standard concerning plugs and outlets for 240v applications, and are the X,Y,G,W wires color specific?
I have seen the two hots also referred to as L1 and L2?

thanks for your answers and sorry for my redundancies but I like to be 110% sure when messing with electric.

thanks
 

Last edited by diy409; 08-14-16 at 09:41 AM.
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Old 08-14-16, 10:24 AM
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is the "coding" X,Y,G,W an industry standard
Yes. Sounds like you now understand it.
 
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Old 08-14-16, 11:32 AM
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The equipment ground will always be green and in some instances may have a "tracer" color like yellow or black added. The "hot" leads will always be some color other than green, white or grey.
 
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Old 08-16-16, 06:54 PM
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I was able to attach the plug as outlined, while the packaging on the new 4 prong listed the terminals as X,Y etc there was nothing listed on the old 3 prong plug.
There were just 3 wires, the obvious ground, a black and white.
What is the difference in nomenclature between X,y, L1, L2. i see some directions stating X,Y. while others use L1,L2.
When dealing with 240 must the black go to L1 and the white to L2 or being that they are both hot is the order irrelevant?

Thanks
 
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Old 08-16-16, 07:13 PM
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White and black are interchangeable on 240 single phase.
 
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Old 08-19-16, 02:33 PM
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Ok
So I ended up putting the black to L1 and the white to L2
And it old be irrelevant if that we're reversed, correct?

To date...
We hooked up the plug and attached it to the generators 240 outlet
The water pump ran for about 15 to 20 seconds and cut off
About every minute or two the pump will com on for a few seconds and than cut out again
Being that the plug is wired correct could this be a particular water pump issue?
I need to check for power at the pump connection when it's in this condition but i had no tester with me at the location.
Just wondering if this might be indicative of a specific water pump issue?
 
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Old 08-19-16, 03:24 PM
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Reversing white and black, L1 and L2, or X and Y would have no effect. What it sounds like is the pump motor has a thermal overload safety device that is cutting power to the motor and then when it cools off it re-connects until again tripping.

Why? I don't know without a whole lot more information.
 
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Old 08-22-16, 10:52 AM
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The generator may be producing insufficient power to drive the pump. It could be that the generator is too small or that the engine speed is not set correctly.

You need to measure the voltage and ideally also the current if you have a clamp meter while the pump is running. What is the size of the pump and generator? What kind of pump is it and how much head is on the pump?
 
 

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