Old Wiring I think that needs to be remedied

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Old 06-22-13, 05:34 AM
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Old Wiring I think that needs to be remedied

While trouble shooting something I took the electrical panel door down and noticed a few things that makes you go "hmmm..."

Now I am not an electrician but even I can see this may be an issue, or two, or even three.

First, I saw two conduits where multiple hot wires and 1 neutral wire go into. One of them was a red, a black, a blue and two white. So there are two circuits sharing one neutral wire. There is another 3/4" conduits with 4 hot and 2 neutral wires going in, but I haven't traced that line yet to see what goes on there.

Back to the conduit with 4 wires, 1 red, 1 black, 1 blue, 2 white. All #12 solid copper wires. The red is on circuit 11, the black on circuit 19.

I read that shared neutral lines must be on opposite legs off a double pole breaker, so that they can trip together, so that one is a no no right there, correct?

So question 1, if I do want to implement this shared neutral configuration, can I move the breaker for circuit 9 to where circuit 19 is, and then put in a double pole breaker to connect the formerly circuit 19 wire and circuit 11 wire to the new 9 and 11 breaker position MEANWHILE still keeping the sticker labels "19" on the wire and breakers? I am asking because I do not want to relabel the stickers on the circuits. Many of the junction boxes have sticker labels on the wire, and if I swap the locations 11 and 19, there is no guarantee I will be able to hunt every label down and relabel them all, I am not worried about labor, I am worried about me missing one label and caused confusion and potential hazard for later. Of course, having a breaker in slot 11 labeled "19" is also confusing, but not as much.

Next, I traced the conduit to the kitchen area. The blue wire and it's neutral goes somewhere else. I found out the red goes to the refrigerator and the other black goes to a bunch of kitchen outlets, the neutral is spliced. At some point in time, someone had replaced a few of the kitchen outlets (not all) with GFCI outlets.

So question #2, I read that a shared neutral line would cause GFCI outlets not work properly, is this correct? I did a search and the answers seem to be mixed, some said yes some said no.

I looked at the conduit which is a 1/2", it's solid wires and I don't think I can pull another white through it, the run is about 80 feet long. So my question #3 is, if I cannot run another white conductor through this, can I run more neutral wire via a separate conduit to arrive at the same junction box? Easier yet, can I run a 12-2 romex cable from the panel to the junction box, but only use the white conductor portion of it?

Thanks for reading this long post, appreciate your input and suggestions.
 
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Old 06-22-13, 06:16 AM
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1. Shared neutral = MWBC, multi-wire branch circuit. Common with raceway and three-phase installations.
2. 2-pole/handle tie requirement for MWBCs was not implemented until the 2000s, although I don't recall which code cycle. Old installations would be grandfathered and are not considered code violations.
3. Formerly there was not even a requirement that the MWBC circuit breakers were in adjacent slots. However if you are updating now, you would need to follow current code requirements. Typically that would mean using adjacent slots and a 2-pole or handle tie.
4. If you move breakers that feed an MWBC, you must be familiar with the bus design to ensure that the breakers are on different poles (phases for three-phase).
5. GFCI on MWBC is not an issue when the GFCI is installed "downstream" from where the neutral splits out to follow one hot.
6. Following the NEC is generally required, but before doing any work make sure you are familiar with the state and local codes adopting the NEC. Most states and many local governments modify the code to make it more or less strict.
 
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Old 06-22-13, 08:01 AM
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2. 2-pole/handle tie requirement for MWBCs was not implemented until the 2000s, although I don't recall which code cycle. Old installations would be grandfathered and are not considered code violations.
It was the 2008 NEC that added this requirement. Circuits #1 and #19 are on opposite legs, I'd leave them where they are, they are grandfathered.
 
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Old 06-22-13, 09:16 AM
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Circuits 11 and 19, not 1 and 19.
 
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Old 06-22-13, 09:34 AM
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I'm not familiar with your panel but if the voltage between the two breakers is ~240 volts it is okay. If ~0 volts one breaker needs to be moved up or down one slot.
 
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Old 06-22-13, 10:22 AM
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Circuits 11 and 19, not 1 and 19.
This, plus your mention of a blue wire, and your comment about the noting of circuit #s at J-boxes down the line, all lead me to believe that you're working on a 3-phase commercial system. (Circuits 11 and 19 are both on Phase B in a 120/240V single-phase system; they are Phase C and Phase A, respectively, in a 120Y/208V 3-phase system.)

If, as you say,
I am not an electrician
why are you working on a commercial installation? What are you attempting to do, and who pulled the permit?

One quick tech note:
I read that shared neutral lines must be on opposite legs off a double pole breaker, so that they can trip together
I'm don't know where you saw that, or if that's what was said, but the actual requirement is for common disconnect, not common trip. That's why the replies talked about
handle tie requirement for MWBCs.
That's two adjacent single-pole breakers with their handles joined with a handle tie. Either breaker can be tripprd on its own, but both must be turned off before doing any work.
 
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Old 06-22-13, 10:57 AM
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No not commercial system, residential. My home, existing wiring, I was doing something unrelated. I just noticed the wiring going up to the conduit out of the panel and they didn't "pair up". No one is doing anything to them I simply traced it to see what's going on.

The blue (and it's neutral) is a totally different circuit. It goes to an outdoor BBQ exhaust fan. It only shared the same conduit.

I have two panels in my home each one serves a different wing.

 

Last edited by MiamiCuse; 06-22-13 at 11:23 AM.
  #8  
Old 06-22-13, 12:51 PM
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Very hard to tell from your picture, but it looks like you have 120/240V single-phase service. If so, then circuits 11 and 19 can't share a neutral. They're both on the same leg of the split-leg service.

Can you recheck that?

Again, it's hard to tell from your picture, but it looks like you have a lot of half-height breakers. If so, Are you numbering each of them with its own number or are you numbering them by full breaker space with a letter for each half?

Just noting, though, that 5b and 9b are also on the same leg. Hmmmm....
 

Last edited by ray2047; 06-22-13 at 01:06 PM. Reason: Typo
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Old 06-22-13, 02:33 PM
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If so, then circuits 11 and 19 can't share a neutral.
That's right. I must have scanned the OP's first post a little too quickly when I replied circuits #1 and #19.

ray is right, put a meter across the two breakers and see what voltage you have?

if the voltage between the two breakers is ~240 volts it is okay.
 
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Old 07-01-13, 07:44 PM
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Sorry, I meant to follow up on this but got side tracked.

Let me summarize what I found.

First, to answer Nashkat1, yes, all the breakers are half height breakers, so whoever labeled them previously as 1, 2, 3, 4, 5, 6 are actually 1A, 2A, 1B, 2B, 3A, 4A respectively.

The circuits who shared a neutral wire, labeled as 11 and 19 are actually 5B and 9B.

So one question is, is labeling this way a problem? I guess I need to stick with this since on the other end, the junction boxes, receptacles, the conductors are labeled the same way.

To answer ray2047, I used a voltmeter and measured between circuit 11 (5B) and 19 (9B) and the reading is 0v.

If I measures between 11 (5B) and 13 (7A) the reading is 240v.

Also between 11 (5B) and 12 (6B) is 0v.

This means 1,3 are on opposite legs of 5,7 and so on.

Now, circuit 13 is now a 20A spare. If I move 19 (9B) to 13 (7A) then I will be all set and a properly made shared neutral configuration right?
 
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Old 07-01-13, 09:33 PM
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The circuits who shared a neutral wire, labeled as 11 and 19 are actually 5B and 9B.
Just noting, though, that 5b and 9b are also on the same leg. Hmmmm....
Whatever else is going on in your panel, circuits 5 and 9 are NOT sharing a neutral. The breakers wouldn't hold for a second. Please re-check the numbering, using a whole number for each full-height (1") space.

So one question is, is labeling this way a problem? I guess I need to stick with this since on the other end, the junction boxes, receptacles, the conductors are labeled the same way.
If you want to leave it in the state of confusion it's in now, it's your house. If it were mine, I would have renumbered (and relettered) every circuit so that I (and anyone else working on it) would know which leg something was fed from.
 
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Old 07-01-13, 10:31 PM
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Whatever else is going on in your panel, circuits 5 and 9 are NOT sharing a neutral. The breakers wouldn't hold for a second. Please re-check the numbering, using a whole number for each full-height (1") space.
I have checked and double checked. It is 5B and 9B. It's functioning. 5B is a 20A breaker for a refrigerator. 9B is also a 20A breaker for a bunch of receptacles in the kitchen but they are hardly ever used.

If you want to leave it in the state of confusion it's in now, it's your house. If it were mine, I would have renumbered (and relettered) every circuit so that I (and anyone else working on it) would know which leg something was fed from.
Understand. It's going to be a tough decision. As you can see I have two panels, they were labeled panel "A" and "B" respectively. Between both panels I have over 60 circuits. Now all labeled incorrectly according to the convention. However, if a circuit in panel B is labeled "21", then where the conduit leads to that wire is labeled "B21" in that box. If that wire is spliced or runs to another box everywhere a wire of this circuit appear they labeled "B21". I would have to open up ALL the junction boxes, receptacles, light fixtures...and relabel every wire in them. That would be a lot of work plus if I make a mistake in the labeling...which is easy, for example "B21" right now mean panel B, circuit 21 but the correct designation is really the second panel, circuit 11A. My head hurts...
 
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Old 07-02-13, 07:48 AM
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It's going to be a tough decision. As you can see I have two panels, they were labeled panel "A" and "B" respectively. Between both panels I have over 60 circuits. Now all labeled incorrectly according to the convention. However, if a circuit in panel B is labeled "21", then where the conduit leads to that wire is labeled "B21" in that box. If that wire is spliced or runs to another box everywhere a wire of this circuit appear they labeled "B21". I would have to open up ALL the junction boxes, receptacles, light fixtures...and relabel every wire in them. That would be a lot of work plus if I make a mistake in the labeling...which is easy, for example "B21" right now mean panel B, circuit 21 but the correct designation is really the second panel, circuit 11A. My head hurts...
I understand. The only suggestion I have at the moment is that you might start by drawing out two panel schedules for each panel - just on paper. You could then compare them to see if you feel that the clarity gained by making the change would be worth the effort. You could also use them, if you decided to change the labeling, as references.

Their decision to label the conductors at each junction and load is unusual in a residential system, but common in commercial work. If that was done accurately within their convention, then following the reference sheets should make the re-marking easier. The A and B designations for the two panels is also conventional. I would keep those, I think, but use lower-case for each half of a full breaker space. B21, for example, would become B11b, at least on the panel schedule. I don't know if that helps, but I thought it might.

I have checked and double checked. It is 5B and 9B. It's functioning. 5B is a 20A breaker for...
Hmmmm...

In the standard NEMA designation system, the breaker spaces on the left side of a panel are odd-numbered, from 1 through 29, say, in a 30-space panel. The spaces on the right are even-numbered, 2 through 30.

The two feed buses feed alternating rows of breakers, thusly:

1 - 2 A
3 - 4 B
5 - 6 A
7 - 8 B
9 - 10 A
11 - 12 B ....etc.

Following that convention, space 5 and space 9 are both connected to leg A and should not be able to share a neutral.

In addition to checking whether the spaces are numbered this way, you can do this test: Set your multimeter to a range of 250 or more VAC - the lowest range it has that is greater than 240. Test the voltage between the wire terminals on 5b and 9b. If you see ~240V they are on different legs. If you see~0v they are on the same leg.
 
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Old 07-02-13, 12:02 PM
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Thanks Nashkat1, I think we are in agreement that 5b and 9b *SHOULD NOT* share a neutral...but as it stands they *DO*. That's why I am concerned and wanted to remedy it. 9b has two receptacles inside the pantry which are rarely if ever used. We have another two circuits from another conduit supply receptacles at the counter space which we plug in microwave, coffee maker etc...perhaps it has worked for many years because the only load on those two circuits was the fridge? There is 0V between 5b and 9b, while there is 240v between 5b and 7a, that's expected right?

I made a label of my PANEL "A". left side of the panel is the first three column, right side is the next three column. The 1st and 4th columns are labeled "Right" or the NEMA designation you spoke of. The 2nd and 5th columns are my current system as labeled. To their right is a brief description.

I shaded those breakers on the same leg with the same color.



5b (my 11) and 9b (my 19) are on the same leg.

7a (my 13) is a spare breaker. I can disconnect the conductor from 9b and reconnect it to 7a, I only need to relabel this one conductor to that refrigerator outlet, it is a single run to there and terminated there. Two labels one on each end. That's the simplest I think. Agreed?

As for the labeling...I hear you.
 
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Old 07-02-13, 12:36 PM
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Great-looking schedule, and fast too.

I think we are in agreement that 5b and 9b *SHOULD NOT* share a neutral...but as it stands they *DO*.
What did you get when you tested for voltage across the two terminals? What makes you think they share a neutral - following wires? What happens when you disconnect that neutral and test at the loads?

7a (my 13) is a spare breaker. I can disconnect the conductor from 9b and reconnect it to 7a, I only need to relabel this one conductor to that refrigerator outlet, it is a single run to there and terminated there. Two labels one on each end. That's the simplest I think.
Yes, but I would NOT move any circuit without first checking for the voltage compatibility if I thought that circuit shared a neutral with another circuit. Getting them crossed - "bumping phases," as it's called - doesn't just get you a circuit that doesn't work. The result can be explosive, and very impressive.
 
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Old 07-02-13, 01:48 PM
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When I tested them at the panel I get 0v. That with everything unplugged and nothing running on those two circuits.

I found they shared a neutral by following the wire. From the panel all the way to the other side where the refrigerator JB/receptacle is one neutral wire spliced into two one goes to the fridge receptacle and the other one follow the other circuit and goes to the rarely used receptacles inside the pantry area.
 
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Old 07-02-13, 09:36 PM
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When I tested them at the panel I get 0v.
Confirmation that they are getting power from the same leg of your service.

With everything still unplugged from those circuits, I would turn those two breakers off and disconnect the neutral from the bus bar. I would look for arcing as I did that (to see if there's a load somewhere that I missed). I would cap the neutral temporarily, turn both breakers back on, and check the receptacles that I know about and all of the other ones in the neighborhood, to see if any others had gone off and to see what code I got on the first three.

Using a plug-in receptacle tester, do they all show "open ground"?
 
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Old 07-07-13, 07:07 PM
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Nashkat1, thanks so much. I did what you suggested, plus I retraced all the conductors again, making sure I know what goes where, me and a friend opened up all the box covers and examined every conduit connected to each, then pull/push/jiggle each conductor to make sure we know which one goes where until we get to all the dead ends.

I am confident all is good now and I got the shared neutral wire implemented properly - on different legs.

The only problem is how would I indicate or mark this at the panel, to make sure I remember these two circuits are part of a MWBC? Is there some sort of electricians' convention? May be I take the two hots and 1 neutral and use a garbage bag twist tie to tie them together or something?
 
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Old 07-07-13, 08:51 PM
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I am confident all is good now and I got the shared neutral wire implemented properly - on different legs.
Good. Did you move 9b up to 7a? Remember to tie the two breaker handles together, if you didn't already.

how would I indicate or mark this at the panel, to make sure I remember these two circuits are part of a MWBC? Is there some sort of electricians' convention? May be I take the two hots and 1 neutral and use a garbage bag twist tie to tie them together or something?
I wouldn't use a twist tie to do that because twist ties typically contain a small steel wire, aka "a conductor."

We typically use cable ties to group sets of wires together. The small 4" ones would be good for this. Just clip off the part that sticks through the lock. You can also add that info to your updated panel schedule. Actually, the handle tie itself should be the best clue.
 
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Old 07-07-13, 11:17 PM
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OK I was kind of kidding about the twisty tie.

I did not move 9b to 7a. Instead I kept 9b where it was, and moved 5b to 11a. The only reason being that that move requires less relabeling of conductors. Since 5b is the line to a refrigerator, and there is no splice at all to that line, I only had to replace the label of the conductor at the panel and at the junction box where the fridge outlet is. If I move 9b, I would have to change everywhere 9b is, which is not too bad I think 5 to 6 places.

Which reminds me. I have been reading up on MWBC a bit on the internet. Now, where it says to implement a MWBC, the neutral must be pigtailed. I assume this means I cannot daisy chain or jump off receptacle's screw terminals from one to the next. OK. Now that means I could not install a GFCI receptacle, then use the load side to feed additional non-GFCI receptacles downstream correct? Because if I did I wouldn't be pigtailing the neutral. I think this is the case but I wanted to make sure. In that case I would just use multiple GFCI receptacles.
 
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Old 07-08-13, 06:18 AM
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For MWBCs I have used electrical tape as well as small cable ties to group the hots and the neutral together. I also have two larger j-boxes, that do not contain devices, with multiple MWBCs in a single conduit, where I have cable-tied the MWBCs.

You are correct that the load terminals on the GFCI cannot be connected as part of the MWBC, and you are correct about how to deal with that. My system is mostly raceway/Greenfield so from the GFCI I would add separate GFCI load side conductors, or if conduit or box fill is an issue I would just use another GFCI downstream on the MWBC.
 
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Old 07-08-13, 07:55 AM
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Now, where it says to implement a MWBC, the neutral must be pigtailed. I assume this means I cannot daisy chain or jump off receptacle's screw terminals from one to the next.
This would be where the two circuits in a multiwire branch circuit are split. The intent is to have a permanent solid neutral connection at the split. If you simply put the neutral conductors on the silver colored screws of a receptacle, one day when the receptacle is being replaced the neutral would be interrupted possibly causing a hazard or excessive voltage on the other circuit. Of course, the 2008 requirement for the breaker handles to be tied together will minimize the hazard.
 
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Old 07-08-13, 01:28 PM
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You are correct that the load terminals on the GFCI cannot be connected as part of the MWBC, and you are correct about how to deal with that. My system is mostly raceway/Greenfield so from the GFCI I would add separate GFCI load side conductors, or if conduit or box fill is an issue I would just use another GFCI downstream on the MWBC.
Box fill is not an issue. I just wanted to clarify what I understood (or think I understood) about using MWBC AND using a GFCI receptacle to protect downstream non-GFCI receptacles are mutually exclusive which you confirmed.

This would be where the two circuits in a multiwire branch circuit are split. The intent is to have a permanent solid neutral connection at the split. If you simply put the neutral conductors on the silver colored screws of a receptacle, one day when the receptacle is being replaced the neutral would be interrupted possibly causing a hazard or excessive voltage on the other circuit. Of course, the 2008 requirement for the breaker handles to be tied together will minimize the hazard.
Hmmm...OK, CausualJoe, if I understand you correctly, you are saying the pigtail neutral conductor requirement is really a layer of protection against ignorance or stupidity if someone were to work on one of the circuits of the MWBC, and neglected to turn off the other circuit at the panel. He/She may get into trouble if some of the neutral connections are not pigtailed and the loop would be interrupted?

If that's the case, then one *COULD* feed and "protect" additional non-GFCI receptacles by wiring the load side even in a MBWC configuration, just that it's not a good idea to do so due to the possibility mentioned above?

If so, wouldn't a handle tie at the panel between the two breakers PLUS where the neutral conductors are connected to the screws of these receptacles, a double label (example: 1b, 3a) on the conductor be a more elegant solution?
 
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Old 07-08-13, 01:59 PM
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If that's the case, then one *COULD* feed and "protect" additional non-GFCI receptacles by wiring the load side even in a MBWC configuration, just that it's not a good idea to do so due to the possibility mentioned above?
Sure you can. The neutral is pigtailed before the first device on either circuit is installed. You can make either or both of the initial devices a GFCI receptacle and daisy-chain standard receptacles off the LOAD terminals until the cows come home. Legal as sunshine, right as rain and done all the time.

A friend of mine did his SABCs for his countertop receptacles this way, using plugmold. He wasn't thrilled to learn that he'd have to install a second neutral in the plugmold to allow the receptacles to be on alternating circuits, but he worked it out. I don't remember now which way he resolved it.
 
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Old 07-08-13, 03:36 PM
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If so, wouldn't a handle tie at the panel between the two breakers PLUS where the neutral conductors are connected to the screws of these receptacles, a double label (example: 1b, 3a) on the conductor be a more elegant solution?
The handle tie or use of a 2 pole breaker is required in the 2008 NEC. Labelling the neutral conductors would be a nice little extra for safety, but they still need to be pigtailed.
 
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