# 220V 3 Wire vs. 4 Wire



## WoodScrap (Feb 6, 2009)

I'm wiring a new shop and have a question regarding using 3 conductor vs. 4 conductor wire for the 220V circuits. Every 220V machine I have ever purchased (some recent) recommend using either a 3 prong twist lock or 3 prong spade plugs. Even new machines are recommending this type plug. I'm being told that the code is electrical code is changing and that soon all machines will reuire 4 prong plugs. I can run 4 wire just as easy as 3 but would seem to indicate I would need to rewire all my current euipment as well. This is not hard but I wonder about the logic to do so. When I look at auto switches and remote switches they are all 3 prong as well.

I'm leaning towards just running the 4 conductor wire but only using 3 wires for now. I can then replace outlets (and rewire the breakers) should that become a code issue in the future. Does this make sense or should I just bite the bullet now and rewire everything for 4 conductor?

Appreciate your thoughts.

Thanks,
Rick


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## Howie (May 25, 2010)

I would think that if the code is not in effect at this time, you would be "grandfathered" if you wire with 3 conductor.


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## lazyoakfarm (Sep 28, 2010)

If its wired now, inspected and signed off on, there will not be a code issue in the future. In Georgia anyway.


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## Jack_T (Feb 6, 2010)

Speak with your local electrical code official. He may have an issue running four wire and not hooking it up to the panel. Since he/she has to sign off on the work you might as well find out what he will sign off on before you do the work.


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## Howie (May 25, 2010)

Right on Jack


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## TopamaxSurvivor (May 2, 2008)

I would go ahead and run the 4 conductor. Leave the neutral in the box unconnected for now if your equipment only requires 2 hots and a ground. At some point in the future the neurtal will be there is you need it. I had a rather interesting discussion with the state the other day about range wiring on existing circuits. Who knows what they will come up with next? The code book is 2x as big as it was 40 years ago, :-(( They occasionally write code ignoring the fact there is no possible way to comply. ;-)


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## bent (May 9, 2008)

the logic for this change is coming from appliance manufacturers. by adding the 4th wire (neutral), they can get 110V for the controls without a transformer. i heard they pushed through this code change to lower their component costs.


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## TopamaxSurvivor (May 2, 2008)

It was put in for household appliances such as ranges sevreral changes back. Not sure how long it was, but late 80s. 120 volt electronics is the bottom line.


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## traupmann (Oct 8, 2010)

Code or not, I have run mine with 4 wire. I ran it all the way to the switch (new wire) and then grounded the table of my saw. I lost a good friend to a 220v shock. I believe in the ground line.


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## TopamaxSurvivor (May 2, 2008)

The older you get, them susceptible you get to electrical shock. Problem is heart in ventricular fibrillation. Older hearts are weaker than young ones. Working in a shop, the chances of shock for hand to hand vs hand to foot is higher. The worse you can get is across the heart. Well, ear to ear is worst ;-)) but what are the odds of that? Current first aide info for electrical shock is to spend 24 hrs in the hosp for observation. The heart can go into ventricular fibrillation that long after the fact.

The bottom line is you wouldn't drive without brakes would you? The ground is the brakes for the electrical systems that trips the breaker and maintains safe voltage reference between conductive (metal) surfaces. Not all faults are overloads; therefore, use ground fault interrupters on your equipment.


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## b2rtch (Jan 20, 2010)

this the difference between one and three phases 
one phase uses three wires, three phases uses four wires ( conductors)

http://wiki.answers.com/Q/How_does_3-phase_electricity_from_power_companies_get_turned_into_single-phase_for_home_use

When I built my shop I wanted 3 phases. the power company told OK no problem, it will cost you only $12000 to bring a line from the end of the block.
phases is much much better, run stuff at 380 volts or 408 even 220 but 3 phases is much more efficient


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## Ken90712 (Sep 2, 2009)

I ran 4 wires to be safe, and figured that I didn't want to redo it on the future if I needed it for a machine. Hot tubs for example, some require a 3 wire and some a 4 wire run. I wasn't sure what type I was going to buy and the fact that it will get replaced, as nothing last for ever these days. I ran a 4 wire to it to be safe.

Better to be Proactive than Reactive. Or as I constantly have to remind myself of something my Grandma said, "Lazy people do things twice." like throwing something to the trash can and missing & having to get up and put it in. She would alway get on me about that. LOL Not saying your lazy, talking about me in this case LOL Good luck!


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