# Breaker torque



## Chris1971 (Dec 27, 2010)

Jon Paul said:


> Hi all: This job the customer wants everything by the book, using 200A AL/CU panel, Square D QO. All panels come with a lug torque label, but breaker ratings seem hard to find, a search f all CB specs showed nothing. Have 15...100A breakers. Anyone ever see a breaker torque spec? Anyone even use a torque wrench on panels or breakers? Many thanks! Jon Paul EE


Sometimes main breaker torque specs are labeled on the panel.


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## Big John (May 23, 2010)

There's this publication from Schneider.  But personally, I'd look at the breakers themselves: It's very often printed on the face or side.


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## Jon Paul (Nov 25, 2013)

*Big John: Exactly!*

This is exactly the info I needed, wonder why its so hard to find on the Schnider website! Enjoy, Jon


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## Paulusgnome (Mar 28, 2009)

Document libraries that are disorganised, disjointed, hard to find, and obscure are sadly not just limited to Schneider.
It is a universal characteristic of all electrical manufacturers.


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## erics37 (May 7, 2009)

If you hear plastic snapping, you're good.


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## brian john (Mar 11, 2007)

And 36 Inch Pounds is hardly anything, having torqued 20 amp QOB's to spec I can tell you 99.9% of connections on QOB's that are not torqued with a calibrated torque screwdriver are way over tightened.

This is one of several torque screw drivers our employees carry.


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## rrolleston (Mar 6, 2012)

How about a 2lb hammer an impact driver and some loctite. :laughing:


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## TOOL_5150 (Aug 27, 2007)

I guarantee you that it says it right on the breaker. Im not being a smart ass... I install Square D panels all the time.


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## daveEM (Nov 18, 2012)

erics37 said:


> If you hear plastic snapping, you're good.


Yeah I like tight.


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## brian john (Mar 11, 2007)

In performing testing I have learned 90% of all electrical connections are over tightened, 9% torqued properly and 1% loose.

That was not data from a Gallop poll but me personal non-scientific WILD ASS GUESS and could be off as much as 100%.:laughing:. Actually I think for a guess it is close to accurate.


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## Big John (May 23, 2010)

Even though I have great confidence in properly torqued terms, without a torque-wrench I always overtighten because I just don't trust how "loose" they feel otherwise.


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## Semi-Ret Electrician (Nov 10, 2011)

We had an electrical manufacture do a demo on the need to properly torque connections, at an IAEI meeting.

In the past they offered $100 to anyone who could properly torque a 200A lug by feel.

Out of about 20 of us only one got it right but it wasn't me


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## Meadow (Jan 14, 2011)

Paulusgnome said:


> Document libraries that are disorganised, disjointed, hard to find, and obscure are sadly not just limited to Schneider.
> It is a universal characteristic of all electrical manufacturers.


Took the words out of my fingers:thumbup:


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## Big John (May 23, 2010)

Semi-Ret Electrician said:


> ..In the past they offered $100 to anyone who could properly torque a 200A lug by feel.
> 
> Out of about 20 of us only one got it right but it wasn't me


 Nuts, what was the tolerance, did it have to be dead-on to win?

I torque a ton of 1/2" bus-bar bolts and I can usually get within a couple foot-pounds by feel alone.


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## Semi-Ret Electrician (Nov 10, 2011)

Big John said:


> Nuts, what was the tolerance, did it have to be dead-on to win?
> 
> I torque a ton of 1/2" bus-bar bolts and I can usually get within a couple foot-pounds by feel alone.


I think they quit doing it because of guys like you!:laughing:

They never said what the tolerance was. But they said they didn't give much money away.

In the Navy we had to torque some 3/4" nuts with a 2 ft wrench to 250 lb-ft. Usually we just hung on the wrench and it was good:laughing:


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## Maximumbob (May 24, 2013)

brian john said:


> And 36 Inch Pounds is hardly anything, having torqued 20 amp QOB's to spec I can tell you 99.9% of connections on QOB's that are not torqued with a calibrated torque screwdriver are way over tightened.
> 
> This is one of several torque screw drivers our employees carry.
> 
> http://www.amazon.com/Wiha-28506-To...1390738483&sr=8-4&keywords=torque+screwdriver


Does that come with a lanyard? I wouldn't want to lose too many of those.


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## brian john (Mar 11, 2007)

Paulusgnome said:


> Document libraries that are disorganised, disjointed, hard to find, and obscure are sadly not just limited to Schneider.
> It is a universal characteristic of all electrical manufacturers.


You will never make it testing circuit breakers, I have to have a manufactures brochure for every circuit breaker we test and we have to read them some are ridiculously long and disjointed. In this day and age it is a lot easier to obtain the data than in pre-internet days.


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## wendon (Sep 27, 2010)

Most breakers with an Allen wrench bolt have the torque specs on them. Most of the SQ QO 200 amp stuff is 250 in lbs. We use a torque wrench all the time on larger breakers, CT cabinet lugs etc. POCO even looks at us a little funny but one split lug on a main breaker will buy you a number of torque wrenches.


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## brian john (Mar 11, 2007)

wendon said:


> Most breakers with an Allen wrench bolt have the torque specs on them. Most of the SQ QO 200 amp stuff is 250 in lbs. We use a torque wrench all the time on larger breakers, CT cabinet lugs etc. POCO even looks at us a little funny but one split lug on a main breaker will buy you a number of torque wrenches.


If you are splitting lugs (NOT YOU PERSONALLY) you are not an electrician your a freaking gorilla.


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## wendon (Sep 27, 2010)

brian john said:


> If you are splitting lugs (NOT YOU PERSONALLY) you are not an electrician your a freaking gorilla.


Not a problem at all. Can't help that I'm not a skinny little wimp like some other's. Split out a Square D 200 amp main breaker lug with a regular 3/8 ratchet. Not much materiel on those lugs.


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## brian john (Mar 11, 2007)

wendon said:


> Not a problem at all. Can't help that I'm not a skinny little wimp like some other's. Split out a Square D 200 amp main breaker lug with a regular 3/8 ratchet. Not much materiel on those lugs.


Square D had some really shallow allen lugs and they would strip out when torqued if you did not lean on the wrench REALLY HARD to insure a tight seated allen wrench.


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## 8V71 (Dec 23, 2011)

Does anybody like to smear a little anti-corrosive compound on the threads of outdoor lugs? I'm not sure if it changes the torque enough to be concerned about but it will always be higher than dry threads.


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## Semi-Ret Electrician (Nov 10, 2011)

All the "Torque Guru's" caution about using lubrication.

I still do but torque about 10% less that the listed values.


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## RePhase277 (Feb 5, 2008)

Semi-Ret Electrician said:


> All the "Torque Guru's" caution about using lubrication.
> 
> I still do but torque about 10% less that the listed values.


Really? I feel like the listed values are too low. I give them just a nudge more. My reasoning is two-fold:

1) Manufacturers would benefit from under-torquing. The more equipment burns up, the more they sell.

2) I've been tightening lugs and screws for 127 years without a torque wrench and none of them have failed, so when I apply the wrench at the spec'd value, it just ain't right!


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## backstay (Feb 3, 2011)

brian john said:


> If you are splitting lugs (NOT YOU PERSONALLY) you are not an electrician your a freaking gorilla.


I have split two CH main breaker lugs with a 3/8 ratchet. It sucks. I also broke the insulater in a 200 amp 1 ph Milbank meter. I did that with a knuckle wrench. That really sucked. I had to have the PoCo come out and change the base.


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## Semi-Ret Electrician (Nov 10, 2011)

RePhase277 said:


> Really? I feel like the listed values are too low. I give them just a nudge more. My reasoning is two-fold:
> 
> 1) Manufacturers would benefit from under-torquing. The more equipment burns up, the more they sell.
> 
> 2) I've been tightening lugs and screws for 127 years without a torque wrench and none of them have failed, so when I apply the wrench at the spec'd value, it just ain't right!


I really don't think a manufacturer would list a low torque value just to sell more panels. If there were a rash of problems they would drive themselves out of business.

I've only been at it for 60 years and when I tore up a few panels by guessing decided to use a torque wrench.

Back in the "good ole days" working on missiles we not only had to torque everything, someone had to witness it. We really didn't want to hit the wrong city.:no:


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## Majewski (Jan 8, 2016)

RePhase277 said:


> Really? I feel like the listed values are too low. I give them just a nudge more. My reasoning is two-fold:
> 
> 1) Manufacturers would benefit from under-torquing. The more equipment burns up, the more they sell.
> 
> 2) I've been tightening lugs and screws for 127 years without a torque wrench and none of them have failed, so when I apply the wrench at the spec'd value, it just ain't right!


Damn Gina, you old!


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## MechanicalDVR (Dec 29, 2007)

backstay said:


> I have split two CH main breaker lugs with a 3/8 ratchet. It sucks. I also broke the insulater in a 200 amp 1 ph Milbank meter. I did that with a knuckle wrench. That really sucked. I had to have the PoCo come out and change the base.


I've broken enough stuff without using a 3/8" ratchet for help! 

It always seems to be at the worst possible times.


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## JoeSparky (Mar 25, 2010)

I carefully torque most small breakers with a #2 robertson driver tip and an M12 impact driver.:laughing:


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## MechanicalDVR (Dec 29, 2007)

JoeSparky said:


> I carefully torque most small breakers with a #2 *robertson driver tip and an M12 impact driver*.:laughing:


I hope you're kidding!:whistling2:


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## Majewski (Jan 8, 2016)

I do German spec.


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## Bird dog (Oct 27, 2015)

This is over a three year old thread.


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## Majewski (Jan 8, 2016)

Yeah, someone likes to add useful info! lol


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## freeagnt54 (Aug 6, 2008)

8V71 said:


> Does anybody like to smear a little anti-corrosive compound on the threads of outdoor lugs? I'm not sure if it changes the torque enough to be concerned about but it will always be higher than dry threads.


If I have it with me, I use noalox on the threads of chairlugs


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## freeagnt54 (Aug 6, 2008)

JoeSparky said:


> I carefully torque most small breakers with a #2 robertson driver tip and an M12 impact driver.:laughing:





MechanicalDVR said:


> I hope you're kidding!:whistling2:


I've done many of panels that way. With a neutral for every phase in 42-84 circuit panels, multiple panels a day for a week. My body has enough aches and creaks, I don't need to add any more wear and tear to my wrist/arm.


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## RePhase277 (Feb 5, 2008)

Semi-Ret Electrician said:


> I really don't think a manufacturer would list a low torque value just to sell more panels. If there were a rash of problems they would drive themselves out of business.


I was being semi-silly, but we know they don't give a hoot about quality. It's profit all the way.



> I've only been at it for 60 years and when I tore up a few panels by guessing decided to use a torque wrench.


I've seen it done, and I've come close myself before, so you get to know what's good. I knew one guy whose motto was: "Turn it until it won't go anymore, then give it another 1/4 turn." In reality, that's how I do with the torque wrench. I torque it to spec, then give it a few degrees more. It turns out that it feels the about the same as it did before I was using a wrench.



> Back in the "good ole days" working on missiles we not only had to torque everything, someone had to witness it. We really didn't want to hit the wrong city.:no:


I'm certain that military spec is meant to accomplish the job. I'm not so confident with cheapo bottom-dollar electrical stuff:laughing: But seriously, I do advocate proper torque, it's just that I happen to believe that proper torque is 5 or 10% above spec.


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## Semi-Ret Electrician (Nov 10, 2011)

Bird dog said:


> This is over a three year old thread.


I realized it was an old tread, but since the new 2017 NEC 110.14 (D) came out we must now use torque wrenches, or al least have one.


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## Semi-Ret Electrician (Nov 10, 2011)

JoeSparky said:


> I carefully torque most small breakers with a #2 robertson driver tip and an M12 impact driver.:laughing:


I'll bet one of the torque settings matches the value listed on the door, for breakers, neutrals & EGC's.

And, a manufacturer will offer an electric torque screwdriver, in the near future, since NEC 110.14 (D) became law.


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## Semi-Ret Electrician (Nov 10, 2011)

RePhase277 said:


> I was being semi-silly, but we know they don't give a hoot about quality. It's profit all the way.
> 
> 
> 
> ...


The get it tight then another 1/4 turn was the norm, until 2017


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## HackWork (Oct 2, 2009)

MechanicalDVR said:


> I hope you're kidding!:whistling2:


I do that for breakers and neutral/ground bars. Never split/broke/stripped a lug or terminal.

Just the other day I said this to myself: it's at the point now that every single time I pickup a screwdriver because I think it'll be quick and easy, I end up sitting there twisting the screw saying to myself that I should have just used the impact gun because I would have been done already.

If I never touch another screwdriver again it'll be too soon.



backstay said:


> I have split two CH main breaker lugs with a 3/8 ratchet. It sucks. I also broke the insulater in a 200 amp 1 ph Milbank meter. I did that with a knuckle wrench. That really sucked. I had to have the PoCo come out and change the base.


My power company has warnings all over the place in the offices where you pickup the meter pans (Milbank brand) saying not to use a ratchet or wrench to tighten the lugs. They say to only use a 1/2" nutdriver. Apparently there has been a lot of broken lugs/insulators. I carry an extra meter pan in the truck so I can change the guts out if I ever break something.


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## emtnut (Mar 1, 2015)

RePhase277 said:


> But seriously, I do advocate proper torque, it's just that I happen to believe that proper torque is 5 or 10% above spec.


I agree 100%.

Torque wrenches are for newbies that don't have the feel yet :whistling2:

Only time I use a torque wrench is on my trucks wheel lugs ... Mfr recommended 105 ft/lbs ... wrench is set for 120 ft/lbs


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## telsa (May 22, 2015)

My troopers have destroyed so many lugs (*) that I torque them down myself - with a torque wrench.

Aluminum is easily damaged when over torqued... resulting in nasty connections.

(*) You'd scarcely believe their lack of restraint. I'd have to use easy-outs to remove the set-screws.

They looked like mashed potatoes -- often enough.

Other times, the lug chassis snapped half-way through.


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## Big John (May 23, 2010)

I take the "I know how tight this should be!" claims with a pound of salt.

I think we all tighten chit a lot more than necessary if we don't got a calibrated wrench.

I just worked with a guy who talked up being a great installer, and I watched him grunting, tighten a 5/16" bolt with two wrenches. It was so damn tight that it turned the washer into a cup and I was sincerely waiting for the bolt to break.

For as important as terminations are to this trade, I really think we just sort of wing it for 90% of them. I'd love to see apprenticeships do more practical classes on what good terms actually look like.


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## RePhase277 (Feb 5, 2008)

emtnut said:


> I agree 100%.
> 
> Torque wrenches are for newbies that don't have the feel yet :whistling2:
> 
> Only time I use a torque wrench is on my trucks wheel lugs ... Mfr recommended 105 ft/lbs ... wrench is set for 120 ft/lbs


This belongs in the "It's an ARC" thread.... ft-lbs, not ft/lbs. The difference is one is a multiplication and one is a division.


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## HackWork (Oct 2, 2009)

Big John said:


> I take the "I know how tight this should be!" claims with a pound of salt.
> 
> I think we all tighten chit a lot more than necessary if we don't got a calibrated wrench.
> 
> ...


I definitely agree with you that apprentices should be taught the proper way. 

But in reality, how much of a problem is this really? Think about the millions of terminations out there. From what I have seen and read, the problems stems from either someone forgetting to tighten the lug/screws (happens more than you think ) or gross over tightening. And I mean someone being stupid, like you mentioned with the guy tightening the 5/16" bolt. All of the rest of the terminations by people making them tight but not stupid-overtight seem to be fine.


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## emtnut (Mar 1, 2015)

RePhase277 said:


> This belongs in the "It's an ARC" thread.... ft-lbs, not ft/lbs. The difference is one is a multiplication and one is a division.


That would explain the lost wheels on the highway 

Thanks RePhase :thumbsup:


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## Bird dog (Oct 27, 2015)

HackWork said:


> I definitely agree with you that apprentices should be taught the proper way.
> 
> But in reality, how much of a problem is this really? Think about the millions of terminations out there. From what I have seen and read, the problems stems from either someone forgetting to tighten the lug/screws (happens more than you think ) or gross over tightening. And I mean someone being stupid, like you mentioned with the guy tightening the 5/16" bolt. All of the rest of the terminations by people making them tight but not stupid-overtight seem to be fine.


My feeling is if it's that critical, use spade crimps & regularly take measurements under load including thermal imaging.


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## JRaef (Mar 23, 2009)

Chris1971 said:


> Sometimes main breaker torque specs are labeled on the panel.





TOOL_5150 said:


> I guarantee you that it says it right on the breaker. Im not being a smart ass... I install Square D panels all the time.





wendon said:


> Most breakers with an Allen wrench bolt have the torque specs on them. Most of the SQ QO 200 amp stuff is 250 in lbs. We use a torque wrench all the time on larger breakers, CT cabinet lugs etc. POCO even looks at us a little funny but one split lug on a main breaker will buy you a number of torque wrenches.


For what it's worth on a zombie thread like this, breakers MUST show the torque values right on the breaker. This is from UL489, the spec for molded case breakers:


> 17. Tightening Torque — All circuit breakers are marked with their rated tightening torque for all terminals intended for field wiring. This is a nominal value. If the torque is dependent on wire size, the marking indicates the range of tightening torques for each wire size.


If you come across a breaker that doesn't show it, that's a clue that it might be counterfeit.


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## nrp3 (Jan 24, 2009)

Anybody come across any counterfeit breakers lately?


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## JRaef (Mar 23, 2009)

Last year, at least that's my suspicion. One of my suppliers who knows I used to work for Siemens lost an order for qty 4,000 15A and 4,000 20A 1P Siemens breakers for a government project, someone on the East Coast was bidding them at $2 each. I know from my experience it cost Siemens a lot more than that to manufacture them, had to be counterfeit.

Either that, or maybe they "fell off of a truck" in New Jersey...


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## HackWork (Oct 2, 2009)

JRaef said:


> Last year, at least that's my suspicion. One of my suppliers who knows I used to work for Siemens lost an order for qty 4,000 15A and 4,000 20A 1P Siemens breakers for a government project, someone on the East Coast was bidding them at $2 each. I know from my experience it cost Siemens a lot more than that to manufacture them, had to be counterfeit.
> 
> Either that, or maybe they "fell off of a truck" in New Jersey...


How much more than $2 does it cost Siemens to make them??? I pay $3 at a large supply house. They just went up to $3.25 the other day.


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## Jarp Habib (May 18, 2014)

RePhase277 said:


> ft-lbs, not ft/lbs. The difference is one is a multiplication and one is a division.


I dunno, one looks like subtraction to me XD


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## MCasey (Dec 7, 2016)

Semi-Ret Electrician said:


> I really don't think a manufacturer would list a low torque value just to sell more panels. If there were a rash of problems they would drive themselves out of business.
> 
> I've only been at it for 60 years and when I tore up a few panels by guessing decided to use a torque wrench.
> 
> *Back in the "good ole days" working on missiles we not only had to torque everything, someone had to witness it*. We really didn't want to hit the wrong city.:no:


We have this often, torqued then marked and logged in a manual then iniitialed by the supervisor and filed. Navy cotracts are a good percentage of our jobs.


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## Baggzy (Aug 14, 2021)

Yesterday I was tightening the lugs on a 3-pole 200 amp Square D QD breaker. The aluminum lugs don't tighten well so I used No-lox on the Allen screws. They would still pinch and seize up. I ended up snapping the connection where the A phase lug connects to the breaker. I still didn't feel like any of the lugs were tight enough but it was impossible to get them any tighter. It was also impossible to loosen them. I've been doing this for 34 years and I've never had this problem before. I don't know if it was because it was so hot and humid in the room or if the breakers just aren't made as good with the shortage of availability of breakers, maybe they're rushing production. I'm pretty sure at 57, I'm not any stronger than I was when I was in my 20's. Lol.
I know. I should have used a torque wrench but I still don't think it should have tightened so suddenly. It just stopped! 
Anyone else run into this? Thanks.


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