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View Full Version : 115 Volt or 230 Volt. How Do I Know?



Keith Starosta
09-03-2009, 3:32 PM
OK...I'll admit it. I don't know how to tell the difference.

I'm installing a new pool pump motor. I've got it all wired, the impeller is good to go, etc. The only thing I'm not sure about is this: There is a toggle on the motor that needs to be set to 230V or 115V...depending on what is running to it. The wire is connected to a 20 amp double-post breaker in the box. How can I determine if this is 115V or 230V?

If this is something I should just inherintly know....please forgive me and don't laugh too hard. :o

- Keith

Von Bickley
09-03-2009, 3:42 PM
Keith,

If it is fed from a double breaker, two breakers tied together, it should be 220 volts.

Mike Cutler
09-03-2009, 3:56 PM
Keith

No it's not something that is intuitive, nor is it a male only gene.
If by the breaker, you mean the breaker in the main service panel, and not a disconnect panel, then the breaker you are describing is "most likely a 240 breaker. The breaker will be occupying 2 slots,and will be physically larger than a single 115 breaker unless you are dealing with a tandem breaker., of which there are a myriad of configurations.

There are some warning bells going off for me though. Most importantly I have never seen a breaker that didn't have some form of label on it that clearly identified what it was, who made it, voltage and amperage rating,UL sticker etc.. This may be the case because what you are looking at could be a molded case two pole disconnect switch. If wired for 220 it disconnects both of the hot legs. if wired for 120 it could be set up to disconnect the hot and the neutral. Since it provides power to a pool pump, it is hard to determine exactly what the code requirements are for your area, an what may have been installed.
A picture would really help folks, and no one should be laughing.;)

Jason Beam
09-03-2009, 4:10 PM
A volt meter should remove all doubt. Test between both leads that are not ground - It should read 220v between those two leads, if it's a 220v circuit.

Matt Meiser
09-03-2009, 4:17 PM
If its a dual pole breaker, should be 220. Assuming someone knew what they were doing when the wired it. Or some hack previous homeowner could have lifted one of the wires off the breaker, attached it to the ground or neutral buss in the panel, and made themselves a 110 circuit, proud of saving themselves the $6 the breaker would have cost. ;) I saw the opposite in my old house--two single pole breakers used to create a 220 circuit.

It sounds like there was an old motor? Could you tell from that?

Dave Johnson29
09-03-2009, 5:32 PM
OK...I'll admit it. I don't know how to tell the difference.


Kieth, go with Jason's suggestion. Don't mess with "it should be," that's some poor advice.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=90899

Tom Veatch
09-03-2009, 7:41 PM
+1 for putting a voltmeter on it. Remove all doubts.

Eric Larsen
09-06-2009, 2:41 AM
+1 for putting a voltmeter on it. Remove all doubts.

Also removes doubts about faulty equipment, suspect outlets, DIY wiring jobs, and in my most recent case, ceiling fan installations.

Get a voltmeter.

Barry McQueary
12-31-2012, 9:39 PM
If the elect. work was done by a real electrician the color of the wires from the breaker to the motor will tell you, There will be 3 wires, One is green, That's the ground, if the other 2 are red and black it's 230v single phase, That equals 2 hot legs and a ground, 110v will be either one red or black, one white and one green, The white is a neutral, So you have one hot leg, one neutral and one ground. if there are 4 wires (which I doubt) then you are dealing with a 3 phase system, Hope this helps