# 240 Volts - 4 wire to 3 wire



## Stubbie (Jan 7, 2007)

You may have some liability issues defeating the equipment ground with an adapter to go from 3 wire to 4 wire. This is done in the RV world but it is usually 4 wire 50 amp to 3 wire 30 amp.

On your present set up those receptacles must have gfci protection.

Maybe just make up a like system for 4 wire only?


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## 220/221 (Oct 9, 2007)

> do I want to drop the neutral or the ground?


 
You don't want to drop either, they must be tied together.

There is no really "proper" way to make your system code compliant with a 3 wire source. Nobodys is going to die but it won't be compliant. The only place where the neutrals and grounds can be together is at the service (where the power first comes to the building),


Be CAREFUL where you plug into. Bars are notorious for having shoddy electrical work. Check voltage and polarity ALWAYS. I was a drummer/sparky many years ago and have seen some stuff. A lost neutral can easily supply 240V to all your 120V outlets. Draw the circuit (with something plugged in/turned on) and you will see how.

One time in Phoenix I got the CRAP shocked out of me setting up my lighting system via reversed polarity in a 120v outlet. A bar in Albuquerque had huge ALLIGATOR CLIPS on the main panel lugs to provide stage power.


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## goose134 (Nov 4, 2007)

Same reason a buddy of mine told me to check the mic with the back of my hand. Sometimes the polarity is wrong. If it wants to grab you it will. If you offer the back of your hand, well the odds are in your favor. Agree 150%. Bars/clubs have some of the most questionable electric around.


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## Richo (Dec 6, 2007)

> Maybe just make up a like system for 4 wire only?


That would be the ideal way to handle it but I have a 150 foot spool of 6/3 cable that I use for long runs when necessary, bought it many years ago when the power sources I was using were mostly all 3 wire. I'd rather not shell out for 150 feet of 6/4.

I'm not so much concerned about being compliant as I am about having good power. Never ran into any truly bad power at bars so far. Other than a hum once in a while I've had pretty good luck getting clean power. 



> A lost neutral can easily supply 240V to all your 120V outlets.


 I experienced this within the last year. The neutral on the socket end of my extension cable somehow worked its way loose after years of use. I lost a number of light bulbs but I use a voltage regulator/power conditioner that protected the delicate electronics. That could have been a disaster and it reminds me that I need to check the cable ends periodically.

Thanks for all of your input.


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## chris75 (Aug 25, 2007)

Richo said:


> I'm not so much concerned about being compliant as I am about having good power. Never ran into any truly bad power at bars so far. Other than a hum once in a while I've had pretty good luck getting clean power.
> 
> Thanks for all of your input.


Hums or buzz's are not related to good/bad power, they are caused from ground loops...


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## Richo (Dec 6, 2007)

The hum usually happens when we're using the bar's wall receptacles instead of getting our own feed off the panel or other 240 V source.


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## J. V. (Jun 1, 2007)

Other than replacing the recept's with GFCI's, I guess you don't have much choice do you? There is no garranty your going to get 4 wires or 3 at any givin bar recept. 
Your panel looks real nice.


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## 220/221 (Oct 9, 2007)

Richo said:


> The hum usually happens when we're using the bar's wall receptacles instead of getting our own feed off the panel or other 240 V source.


 
The hums usually happened when we got too buzzed and forgot the lyrics.


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## goose134 (Nov 4, 2007)

> The hums usually happened when we got too buzzed and forgot the lyrics.


:laughing::laughing:


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## UBoiler (Nov 7, 2007)

LOLOLOLOLOLOLOLOLOLOLOLOLOLOL. Thanks.


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## lg 38 (Feb 23, 2008)

what is a ground loop


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## chris75 (Aug 25, 2007)

lg 38 said:


> what is a ground loop


http://ecmweb.com/grounding/electric_finding_fixing_ground/


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## InPhase277 (Feb 9, 2008)

Richo said:


> I play in a band and sometimes the place we're playing doesn't have enough dedicated circuits nearby for our equipment but often times they will have a 240V receptacle available.
> 
> I have a 6 circuit "sub-panel" that I built and use for this purpose with a 3-wire NEMA 10-50 matching range cord. In this box I have the neutral bar tied to the box/ground.
> 
> ...


Well.... there's really no correct way in your case... Only less wrong ways:whistling2:.

But, if you have to make an adapter, then you would want to drop the ground from the 4-wire setup. I know I will probably get flamed from others for that, but my reasoning is that if you drop the neutral, then your neutral current from your rig will return on the ground of the system, that isn't ideal.

Since you are going to make it anyway, and you are going to use the 3-wire setup, you're better off loosing the ground in the 4-wire. And as others have pointed out, GFCI receptacles would be ideal in this case, but...

InPhase277


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## jrclen (Feb 20, 2008)

In my humble opinion only:

Assisting you do something wrong is really not what professional electricians should be doing. I see a sub panel in your picture. The grounding (ground) conductor cannot be bonded to the grounded (neutral) conductor in that panel. Your cord is a feeder and must be 4 wire. The fact that you don't wish to spend the money for a new cord does not change either the electric code nor the safety reasons for those code articles.

Any bar having a three wire, 240 volt circuit, supplying 120 volt loads needs to take a little of their profit and correct that violation.

I'm not trying to be the bad guy here, or rain on anyone's parade, but if someone gets hurt or killed, I'd would hate to hear "a licensed electrician told me this was ok." All of us look bad at that point.

I thought about just skipping this thread and letting it go, but I just wouldn't feel right having read it. So there is my 2 cents. For what it's worth.


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## InPhase277 (Feb 9, 2008)

jrclen said:


> In my humble opinion only:
> 
> Assisting you do something wrong is really not what professional electricians should be doing. I see a sub panel in your picture. The grounding (ground) conductor cannot be bonded to the grounded (neutral) conductor in that panel. Your cord is a feeder and must be 4 wire. The fact that you don't wish to spend the money for a new cord does not change either the electric code nor the safety reasons for those code articles.
> 
> ...


I agree completely. However, it is likely that the OP will do whatever it takes anyway. no matter what we say. A traveling band can't very well demand a bar owner call an electrician a couple hours before a show to come in and run a 4-wire circuit to the stage.

Like I said, he is going to do whatever it takes anyway, so while I won't say you should do it wrong, I will suggest a "less wrong" way to do it. If we don't chime in, he may do it way wrong, and really F-something up.

We have ranges and dryers all over the country wired this way, and while not ideal, this is a similar situation.

InPhase277


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## Richo (Dec 6, 2007)

Thanks guys, I appreciate all the advice.

Here's another related question:

Sometimes the bars don't have a 240 receptacle available and I have to go directly into the panel to get my power. I have 50 amp double pole breakers of all of the standard brands and I simply snap in a breaker. Since I have only 3 wires, would I be correct (or should I say, 'less wrong') in attaching the 3rd wire to the ground in the panel, not the neutral? Some of these older places don't even have a separate ground in the box and the neutral bar is tied to the box so there is only one option at those places.

I will be changing the receptacles to GFIs...

Thanks again!


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## 220/221 (Oct 9, 2007)

I played in a Albuquerque bar called Alphalpha's in the late 70's. They left the panel cover off in the hallway leading to the restrooms. For stage power they had a big old SO cord attached to the MAIN LUGS with ALLIGATOR CLIPS!



Safety first !


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## Richo (Dec 6, 2007)

The alligator clips....that's an accident waiting to happen...

Never ran into a place with any such situation but I have heard of bands doing that before, alligator clips, rubber gloves & boots, etc. I'm not afraid to go inside a panel but you won't catch me touching the live bus.


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## InPhase277 (Feb 9, 2008)

Richo said:


> Thanks guys, I appreciate all the advice.
> 
> Here's another related question:
> 
> ...


The neutral
InPhase277


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## bullet (Jan 26, 2008)

Can you take a picture of that box with the cover off?


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## Richo (Dec 6, 2007)

I'd have to dig it out of the truck.....wondering what you want to see....


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## jrclen (Feb 20, 2008)

InPhase277 said:


> We have ranges and dryers all over the country wired this way, and while not ideal, this is a similar situation.
> InPhase277


I hear what you are saying. Ranges and dryers are not supplying multiple loads through a load center. Not even close to being similar. You can help him do a hack job if you want, I just wanted to say what I said. And a simple call to the AHJ (local fire departments are good too) if there is one, will get the receptacle outlet brought into compliance in a commercial location pretty quickly in most areas. I won't be debating this with you. I said what I wanted to say. You guys go ahead and do whatever you want. :no:


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## bullet (Jan 26, 2008)

The box you made looks pretty good, I just wanted to see how it was all connected internally, no worries if you can't get a pic.


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## RobertS (Feb 2, 2008)

You need to make a 4 wire panel, and it won't be cheep. I would wire it the same as an R.V. Up to a 50 amp main breaker( if you use a range cord)( 30 amps for a dryer cord), isolate the neutral from the ground in the pannel. Use all G.F.I. breakers. You will need to 3 wire all of the receptacle boxes and, use a grounding pigtail on each box. Connect each ground wire to the pigtail with a ground crimp ring, and then run it to the receptacle ground screw. I would use MC wire to the boxes. Most home centers sell it in 25 ft boxes now a days. For the old box I would put in all new GFI breakers. You can get GFI protected extension cords, or plug in GFI adaptors for the old box, but again they ain't cheep. Check out some of the GFI products at Technology Research Corporation, Clear Water Florida. Why wouldn't that qualify as a temporary under article 590.4(C). Even with a 4 wire if he had to hook up the ground, and neutral to one ground bar it will give 4 wire protection. His 50 amp breaker is an approved panelboard.( Maybe)


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## goneracin (Dec 12, 2008)

I just stumbled onto this site, and have this same situation.


My thinking on my panel is
wire it with separate ground and neutral (4 wire) and put a 4 wire receptacle on the outside of the box.
Then I can make a 4 wire cable to run for a normal 4 wire house setup.
AND
make a cable that has the 4 wire on one end (to plug into my box) and a 3 wire plug on the other with the ground and neutral tied together on the 3 wire end.

Would this be the "least wrong" and safest method? 

It will give the added expense of an additional cable, but the 3 wire to 4 wire adapter cable can be short.
I will of course make the box with gfci receptacles


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