Wiring 2 outlets from 2 circuits in 1 box


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Old 03-07-07, 03:52 PM
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Wiring 2 outlets from 2 circuits in 1 box

Hi All,

I have two hot 110v lines and one neutral. I need to wire two outlets into one box each on their own circuit. I wanted to make sure my thinking is correct before proceeding. Since my two hot lines are each on their own circuit I would obviously connect one hot to each outlet on the proper side. Next wire the neutral to the first outlet then using the other post on the neutral side run a neutral to the second outlet. Is this correct? It didn't seem like I would need another neutral since the two hots are on the same panel.

Thanks,
Mark
 
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Old 03-07-07, 03:57 PM
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the two hots MUST be on opposing legs in the panel. Otherwise, not only is it against code, it can also be dangersous since it can effectively doulbe the current on the neutral.

also the neutral cannot be broken when you go from the one recep to the other.

I typically pigtail both receps and tie that to the common neutral.
 
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Old 03-07-07, 04:07 PM
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Thinking Right

Your thinking is correct when you are guessing that you can use a shared neutral for the the two hot lines, however , always check with local electrical areas in your area. I am an electrician in Nova Scotia , Canada and even though the shared neutral will work just fine (when connected properly) the inspection authority in our area frowns upon this practice because of the possibility of an open neutral (wierd things can happen when you get this situation). My advice is if you are going to share a neutral then do NOT use the screw terminals on the receptacle to join the neutrals, you really should splice the wires and add a pigtail on to the splice and feed the neutral side of the receptacle with this tail. It allows for changing this receptacle (in the event that it is damaged or worn and loose) without removing the protection of the neutral at the next receptacle. As I stated, check with someone about local codes governing this installation first, the rules in your area may not allow such an install and since I am used to doing work to meet Canadian Electrical Code , I cant advice you about codes in your area. Good luck, be safe and always turn the power off before doing any electrical renovations.
 
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Old 03-07-07, 04:32 PM
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This set of wires may have been used as 220v but does that mean for sure that the hots are on opposite legs of the panel? It seems like in some situations they may be on the same side. It's all 12 guage in conduit and is currently up to code so I want to make sure it stays that way. If I have any serious doubts I"ll just use one of the hot legs for now and just wire the outlets in a series. This circuit(s) was capped off in a junction box at the top of the wall and I just need to make a drop and wire a duplex. Using both circuits would my ultimate goal though.

Many Thanks,
Mark
 
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Old 03-07-07, 06:26 PM
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if it was a 240 volt circuit and it is still hooked up the same way, then yes, they would be on opposong legs.

If you have a voltmeter, you can check by measuring the voltage between the 2 hots. It will read ~240 volts if they are on oppossing legs. If they are on the same leg, it will read 0 volts.

most panels have both legs on each side of the panel alternating between the two as you progress downward.
 
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Old 03-07-07, 06:38 PM
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If the hot wires are properly connected to opposite legs of the incoming 240 then you can do this.

However, the neutral wire must be pigtailed. You are not allowed to connect the neutral directly to either device.
 
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Old 03-07-07, 06:46 PM
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Bob, can you direct me to the code section that requires this. As I understand the section, you cannot utilize the device to continue the nreitral but if you were to loop it on the first one that this would be legit.

I personally prefer to pigtail anyway but would like to read that section as well. I cannot seem to locate it in the NEC.
 
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Old 03-07-07, 06:53 PM
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Nuetral

All above is true. Just make sure the neutral is terminated at the panel.

Check hot to hot 240/220 +-V to each other. then 120+-V to the neutral from each one. Then you should be good. Don't forget the ground.
 
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Old 03-08-07, 05:15 AM
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Hi All,

I had already measured each hot to the the neutral and they are 120v on each. I have not checked the hot to hot voltage yet. I have a basic line tester light that is good up to 270v (Has four lights 120v, 220v, 240v and 270v). So I would just put one post from my tester on one of the hots and the the remaining post on the other?

There are only these three wires in this conduit and the conduit goes from the panel directly to this junction box so it doesn't branch off to anything else. So as far as grounding the outlets should I run a short ground lead from each outlet to the box or will just connecting them to the box ground them properly? It's a 4" metal work box mounted to cinder block.

Thanks to all for your help.
Mark
 
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Old 03-08-07, 05:33 AM
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To measure the voltage between the two hot wires you place one probe on each hot wire. How else could you possibly do so?

You have no ground wire. While conduit can and does (when the proper type of conduit is used and when the conduit is properly installed) provide a ground, I prefer that a separate ground wire be used. I suggest that you pull a ground wire through the conduit all the way to the panel.
 
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Old 03-08-07, 07:29 AM
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Talking

The voltage of the two hots is 240v so they are on opposing legs of the panel. I also verified that the neutral does terminate at the panel and the conduit is properly grounded.

Thanks a bunch
 
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Old 03-08-07, 07:45 AM
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I still recommend that you run a ground wire in the conduit.
 
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Old 03-08-07, 08:16 AM
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Shouldn't the panel be turned off before running new wire into it?
I can't shut this panel off because it would shut off circuits that aren't mine.
 
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Old 03-08-07, 08:18 AM
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I sense a problem here. If this panel isn;t yours, then perhaps you shouldn't be doing this work at all.

Is this your house, that you own? How come this panel contains someone else's circuits.
 
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Old 03-08-07, 04:55 PM
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Ya, So whats up?

These are things we need to know.
If you are also messing with someone else, DON"T! Call the landlord and get it done. This is foolish, and the liability on you...

I'm almost speachless every time this comes up.

IF YOU DON'T OWN IT. Don't mess with it. Once you touch it... you own it.

Now back to the start. Answers will change.
 
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Old 03-10-07, 08:36 AM
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Sorry, I wasn't clear. I didn't mean to imply the panel wasn't mine. I'm the owner. I'm currently allowing a friend to use a couple of rooms for a server/render farm. It consists of about 30 computers and those circuits are on the same panel. He can't shut them down until a scheduled time which is a couple of weeks away. This is a temporary situation while he moves his business to another location. I'm a photographer and converted my garage to a studio and need some extra power. The previous owner had removed a drop from this junction box in my garage, you can see where things were mounted, and I just want to put the drop back and wire it as two 110 outlets. All the wires are 12 ga solid in metal conduit. Once his equipment is out I can turn off the panel to run a ground. I'll just leave the supply capped, install the drop and wait until I can turn off the panel to finish it.

Thanks
MT
 
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Old 03-10-07, 04:48 PM
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Using Conduit For Bonding

As mentioned earlier by racraft, the metal conduit if properly installed ,may be used as your bond (ground) up to that junction box ( the 4" square box). If you are unsure about pulling a new bond wire from the live panel to the junction box then use the metal conduit as your bond as long as you can ensure that it is effectively grounded. I do recommend having a seperate bond wire from the receptacles to the box and not simply relying on the device mounting screws to ground the receptacles. When you are able to turn off this panel install the ground wire at that time.
 
 

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