# Old GE TQL Breakers and Short-Circuit Current



## Jump-start (Sep 26, 2012)

What is the actual AIC of these breakers? Do you have any pics of the panel?

Replacing the breakers would be easy and relatively inexpensive compared to other brands. 

The handle ties sound like the trip indicating versions, but a pic would confirm. 


BTW, some of those 240 volt circuits might be a code violation without common trip.


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## GrampaDave (Dec 4, 2014)

Here are pictures. (Don't get sidetracked by the double-lug; I'm going to fix that.) The panel photo is rotated clockwise; top is on the right.

By the way, this panel seems to be an oddball among split-bus designs, with the main disconnects in the center and the subs above and below.

The datasheet I referred to is at https://www.platt.com/CutSheets/GE Breakers/THQP.pdf .

TQL 10A has a "not UL listed" AIC rating of 5KA. 15A and 20A are "not UL listed", period, and I guess the 30, 40, and 50 were obsolete by 1999, because they're not mentioned at all.

What's a "trip-indicating" handle tie? Trip is indicated by the handle being in center position, isn't it? Or is this type of tie for the special case where only one pole sees overcurrent? I sure hope both shut off!

<reads another datasheet>

I think I get it. And I don't like it. None of my six main disconnects has common trip. The difference between a trip-indicating handle tie and a solid handle tie is merely that with the former you can tell which one of the ganged breakers has tripped, because of the displacement of the tripped handle. But in either case, a trip leaves the other pole live. When would you want that, other than the degenerate case where you're using the breakers as switches only, not as OCPD's?

If code requires common trip on main disconnects, how did this panel pass inspection? Or was it okay on 1959 code?

Thanks,
Dave


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## micromind (Mar 9, 2008)

Generally speaking, available fault current isn't much of an issue on a basic residential service. It's pretty rare to see one that even comes close to 10,000 amps, the vast majority are less than 5000. 

It's also very rare to see a bolted fault (dead short) in an operating system, they're almost always arcing faults. Even if the system is capable of more that 10KA, it's pretty hard to get that amount of current with an arcing fault. 

With breakers that old, I'd be more concerned that they wouldn't trip at all, regardless of current. This is usually because the springs get weak and simply don't have the mechanical strength to trip the contacts open. 

As far as I know, new GE breakers will fit that panel. They're not very expensive. 

50s are ok for the two subs (60s might be ok, if so, it'll state on the label), 40 is ok for the range (#8 or larger wire), 30 is ok for the water heater (#10 or larger wire), but since the dryer uses a 30 amp receptacle, it's limited to a 30 amp breaker.


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## ritelec (Aug 30, 2009)

Lot going on for eighteen circuits.

I'd toss a coin.

Leave it alone (but you'll always be thinking about it).
Or replace the panel.

With the panel replacement, you will probably have to deal with the lines in and grounding also.

If you leave it alone, you can go out for a hamburger.


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## GrampaDave (Dec 4, 2014)

Thanks, I wondered if I was spending energy worrying about an unlikely case. For what it's worth, my street is served by a single thin phase wire that's tapped off a thicker three-phase line at the end of the block. The wire feeds two or three pole transformers with secondaries paralleled via service cable strung at lower height.

My dryer uses a 50A receptacle, don't remember the NEMA number, but it's the big crowfoot. The wire is #8, same as the range.

The label in the panel says the subs can be 50A or 70A, depending on the wire size used for the link. I can't remember ANY overload trips in the ten years I've lived here, so I'll stick with 50. I'll start exercising them (5 on-off cycles) once a year. Got any suggestions for a cheap temporary load bank an HO like me could use to simulate overloads? I can do three hair dryers to pop the 15's, but I can't think of anything good for the bigger breakers.

Do you think I should just go ahead and replace the main breakers anyway, on account of sheer age rather than AIC? THQL2130/40/50 are pretty cheap, but when I exercise the old ones, they feel like new, and I hate to throw out stuff that works. Not that I'm certain that smooth feeling means anything, trip != operate.


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## GrampaDave (Dec 4, 2014)

Was it code compliant in 1959 to gang single-pole breakers (no common trip) as double-pole main disconnects? I can't imagine that being permitted today.


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## Jump-start (Sep 26, 2012)

GrampaDave said:


> Was it code compliant in 1959 to gang single-pole breakers (no common trip) as double-pole main disconnects? I can't imagine that being permitted today.


If the load is straight 240 volts like a water heater code still allows it. However, if both 120 and 240 is served a common trip is required.

The dryer should be 30amps and a NEMA 10-30 unless the dryer does indeed pull over 30amps. 


Replacing those breakers would be a breeze. GE breakers are amongst the cheapest available at home Depot. Common trip is a really good idea for all 240 volts circuits and code when dealing with 120/240 circuits like a dryer.


I agree with Micromind, he is spot on as always. Breakers that old are at much higher change to fail, so new ones will be a great investment. 

FWIW, that panel looks to be in really good shape, and not a bad vintage either


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## GrampaDave (Dec 4, 2014)

Thank you, gentlemen! Sounds like the contractor got a deal on single-pole breakers.

I will replace all the main disconnects with common-trip model THQL2150 and so on. Christmas present for the house.

The dryer nameplate is 25A at 240V. The receptacle is a NEMA 10-50, used with both dryers and ranges for decades prior to the split into 10-30 and 14-60. Since the wire is #8 in both cases, a 40A breaker is okay in both cases, isn't it?

Then I'll do the branches. Several are 240V heating loads. 
As for testing the 120V circuits... let's see, I have a space heater, a hot plate, two vacuum cleaners and two hair dryers. That should pop a 20 in a couple minutes.


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## GrampaDave (Dec 4, 2014)

The deal's done. All new breakers (except for the two branches that were already new), less than one hundred bucks. Thanks again.


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## micromind (Mar 9, 2008)

GrampaDave said:


> The deal's done. All new breakers (except for the two branches that were already new), less than one hundred bucks. Thanks again.


Good work........you'll sleep better at night........lol.

Yes, I know how difficult it is to throw out things that may be perfectly fine, but considering what can happen if one of the old breakers fails to trip during a fault, it's worth it.


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## Jump-start (Sep 26, 2012)

GrampaDave said:


> The deal's done. All new breakers (except for the two branches that were already new), less than one hundred bucks. Thanks again.


Just to point out one of those new breakers looks like a Siemens or Murray, which might not fit electrically. But a GE breaker will fix that


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## GrampaDave (Dec 4, 2014)

Oops, missed that. That's not a UL Classified combination, as far as I can tell.


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## Jump-start (Sep 26, 2012)

GrampaDave said:


> Oops, missed that. That's not a UL Classified combination, as far as I can tell.


Correct, breakers must match the panel. A few exceptions exist, but in this case its not worth the gamble.


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## GrampaDave (Dec 4, 2014)

I got all the new breakers in, except one that hasn't arrived yet.


They don't quite fit! :furious:

Although they seat firmly and make excellent, positive contact to the stabs, they don't appear to accept the stab as deeply as the old TQL's. This tilts them slightly, which "lifts and separates" to the point where the cover won't seat over them.

I've sent a query to GE Customer Support.

I thought THQL is the approved replacement for TQL.
By the way, I see two different styles of THQL. Different plants, different date codes? Anyway, one kind is worse than the other. Unfortunately, that's what I mostly got. 

What's the received wisdom? Enlarge the openings? File down the stabs? Choke and die?

Here are some pictures. I'll get better ones in the daylight tomorrow if you need them.


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## GrampaDave (Dec 4, 2014)

GE changed the way they set the breaker's seating height. In my panel, you push the breaker down until the top of the molded slot rests on the stab. TQL breakers, THQL Issue UOxxx (probably MJxxx, NExxx and others too), and also Siemens QP and Eaton BR, can work this way, because they all have the same slot profile.

Recent panels have a ridge of insulating material next to the stab; the bottom of the breaker's case rests on the ridge. The stab is not as tall. It doesn't penetrate the breaker as deep. All the above breakers (except TQL which somehow doesn't quite fit) can be mounted. Also Issue RT-xxx of THQL, which doesn't fit the old bus because it can't accommodate the tall stab. Issue RT-xxx is all you will find in retail stock.

So what do you think I should do? I want to cut down the stubs, but my wife is afraid she will find a crispy critter in the garage.


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## Stubbie (Jan 7, 2007)

GrampaDave said:


> GE changed the way they set the breaker's seating height. In my panel, you push the breaker down until the top of the molded slot rests on the stab. TQL breakers, THQL Issue UOxxx (probably MJxxx, NExxx and others too), and also Siemens QP and Eaton BR, can work this way, because they all have the same slot profile.
> 
> Recent panels have a ridge of insulating material next to the stab; the bottom of the breaker's case rests on the ridge. The stab is not as tall. It doesn't penetrate the breaker as deep. All the above breakers (except TQL which somehow doesn't quite fit) can be mounted. Also Issue RT-xxx of THQL, which doesn't fit the old bus because it can't accommodate the tall stab. Issue RT-xxx is all you will find in retail stock.
> 
> So what do you think I should do? I want to cut down the stubs, but my wife is afraid she will find a crispy critter in the garage.


 Don't do that.

Replace the panel .. looks to me like your up to it. Might have to hire an electrician if local codes require it. If you are allowed to do it yourself and prefer to save a buck come back here and we will help you through the process.


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## GrampaDave (Dec 4, 2014)

*Huge success*

[Moderator: Can you change the thread title to "New GE breakers in old GE panel"? Thanks.]

Sorry, Stubbie, I already did it. I woke up in the middle of the night knowing how. Next day... my breakers are *sitting pretty*!

1. Put a nonconducting shield around the stab being worked
2. Double-glove and wear thick long sleeves
3. Mask and goggles
4. Stand on an insulated pad or riser
5. Run tool and work-light through an isolation transformer

The shield doesn't have to be anything fancy. Mine was scraps of wood paneling. It covers the breakers below the work to prevent falling-debris surprises. I covered the stab above the work with a pair of single-pole breakers. Since this is a split-bus panel, I only had to work "hot" with the six main stabs.

I used a Dremel with a cutoff wheel to remove exactly 1/8" of height off each stab. This leaves 5/8", more than enough for full contact, even with the old TQL's.

I'm not going to _urge_ other owners of old GE panels to do this... but... if you have a burning desire to put in new _GE_ breakers (as opposed to QP's or BR's), this approach is dirt-cheap, and not as difficult or scary as I thought. Just keep respecting that 240V non-stop.

A side note. I had been waiting for one last breaker, and it arrived this afternoon. It wouldn't go in! Turns out this panel has a mis-aimed spot weld which changes the spacing between these two mounting hooks. No problem until you try a genuine double-pole breaker. A few more minutes with the Dremel and Bob's your uncle.


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## mm11 (Apr 30, 2013)

Modifying a panel voids any listing of that panel. Not a good idea.


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## Jump-start (Sep 26, 2012)

Sawing off parts of the stabs might cause problems down the road. like a melt down. Also wood can dry out and catch fire because the trickling current through it literally dries it out turning it into charcoal. 


At this point replacing the panel is the only option. Its not expensive either as a new 200amp GE panel can be acquired for $150.


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## GrampaDave (Dec 4, 2014)

I didn't make it clear, JS; the shield was only for my safety while I was working. I wouldn't dream of filling my panel with combustibles.

Why will it cause a meltdown? The breaker makes full contact, just as it did before. I checked and measured. I should have taken a picture. If you ask, I will go back in and do so.

$150 _plus labor_ is very expensive, to me. The breakers were all I could manage.

I got a very "Microsoft" reply from GE tech support: Yes it fits, and if it doesn't, buy a new panel. It is to laugh.

SUMMARY
-----------------------------------
Old-GE HO's who want/need to replace a breaker have three lawful options:

1. Replace 50-year-old TQL with other 50-year-old TQL
2. Install THQL, Issue UOxxx or older (NOS only), _not_ Issue RT-xxx (current)
3. Replace the panel

In other words, you're screwed. :surrender:
-----------------------------------

If you don't feel so lawful :whistling2::

4. Install QP or BR
5. Modify the panel per my small contribution to our collective knowledge

If I had infinite time and energy, or infinite wealth, I would replace it, sure.
As it is, I don't see a stab-check in my lifetime.* Let the next guy bite the bullet; I'm tired.

Dave

* He _might_ glance at the panel, see GE, and call it good. If he says, _"Wait a minute, those shouldn't fit,"_ I'll drop dead from astonishment.


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## Jump-start (Sep 26, 2012)

The melt down could come from poor contact. It depends how the buss was filed down and how much. If any breaker isn't gripping well that connection could arc/overheat causing the buss bar to melt or the plastic to catch fire.

Also, keep in mind this is a split buss panel. If a stab began to heat up over time to the point the insulating material behind the buss failed the buss bar could short to the metal back pan. In the sub main section the breaker would catch it, but in the main section the fault would continue until something from the POCO stops it. What that is and how long is unknown but a worst case scenario is the service conductors literally melting.


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## GrampaDave (Dec 4, 2014)

It grips as well as it did before the mod. It simply grips a different patch of stab. The portion removed played no electrical role. It never touched the contact patch of the breaker's fingers, except to swipe past during insertion. The only effect of the removed portion (before it was removed) was to mechanically prevent full seating.

The buss insulation is Bakelite, as far as I can tell, same as the breaker case. Or some kind of thermoset anyway. You gave me an idea. I will pick a heavily-used stab and check its temperature now and then. If it gets uncomfortable, then the case is closed, and new THQL is out, period. Being realistic, I don't expect anyone to do what I did, but many many people would just bolt the cover on even if it didn't fit.

Since GE (or at least its representative de jur) is unaware of the incompatibility, I am not sure that they considered new THQL's use in old panels. We know they didn't test it! Therefore they may have inadvertently equipped it with contacts which are, in fact, inappropriate to old stabs. The old stab, stamped from copper sheet into a corrugated shape*, is quite different from modern solid aluminum(?) ones. The RT-xxx fingers contact a smaller area of stab than UOxxx and previous. (QP and BR have a large contact patch too.)

* Measuring from peak to peak of the corrugations, the old stab is the same thickness - 3/32" - as the modern solid stab, but old-style fingers touch more peaks.

At the same time I argue my case, I acknowledge that modification of equipment is beyond the pale, unthinkable in the ordinary course of business. I did it because, of the two options that are real options for me, it is less likely to be detected. (Also, I have the designer's outlook, where everything is raw material and opportunity. Changing things so they work is my hobby.)


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## Jump-start (Sep 26, 2012)

YOu might luck out, and I would trust you more than someone else since it appears you understand this well, but still its a gamble.


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## GrampaDave (Dec 4, 2014)

Thank you for getting my ornery streak going. I did the temperature run -- *FAIL!* After an hour at 40A per pole, the stab was up to 80 deg C (75 degrees rise) and the breaker did a thermal trip.

Issue RT THQL breakers employ a smaller contact patch. This patch is short enough that it does not span from one peak of old-stab corrugation* to the next, resulting in insufficient area and pressure. Issue RT's are TOTALLY INCOMPATIBLE with old GE panels, and my proposed modification is out the window. (Issue UO and older are okay and don't require the modification but they are only available on the secondary market.)

I stuck the old TQL's back in and continued the load run. After a half hour it stabilized at 35 degrees (only 30 degrees rise). I don't care if they are old, they are staying put. I'm sorry I ever conceived this misbegotten "project", except for the knowledge gained.

Dave

* For the record, old-panel stabs are .050" copper sheet, about .085" peak to peak including the corrugation. New stabs are solid aluminum (I think) and measure .093" .


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## Jump-start (Sep 26, 2012)

How many of the old stabs did you saw off? There is a good chance the sawn off stabs wont fit the old breakers either.


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## GrampaDave (Dec 4, 2014)

All of them. The old breakers still fit, and run cool.


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## Jump-start (Sep 26, 2012)

GrampaDave said:


> All of them. The old breakers still fit, and run cool.


Far from ideal... but if you are 100% certain the old breaker tabs grip the same area of metal... it will be fine. But the key is 100%. 

I am going to be honest, you should have asked here before sawing off the tabs. I would have told you to just put the older breakers back and return the new ones. When DIYs go ahead and do things without running it by a pro hazards are introduced, some dangerous. 

For the time being, keep an eye on the heat. Make sure those stabs are indeed working as designed.


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## GrampaDave (Dec 4, 2014)

Yes, they grip the same. With these corrugated stabs, it's not area per se, rather, how many peaks are contacted. I didn't remove a peak. The material I removed did not touch the finger. Going one hour at 40A (plus another 18A from the other breaker on the same stab), I see 30 deg C rise on a thermocouple touching the stab.

I totally should have asked. I was blinded by the excitement of moving forward.
I hope the record of my experience here dissuades the next eager beaver from trying it.


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## Jump-start (Sep 26, 2012)

GrampaDave said:


> Yes, they grip the same. With these corrugated stabs, it's not area per se, rather, how many peaks are contacted. I didn't remove a peak. The material I removed did not touch the finger. Going one hour at 40A (plus another 18A from the other breaker on the same stab), I see 30 deg C rise on a thermocouple touching the stab.
> 
> I totally should have asked. I was blinded by the excitement of moving forward.
> I hope the record of my experience here dissuades the next eager beaver from trying it.


Don't try this at home kids! 

Anyway, hopefully everything stays as is. And I agree, don't modify your panel without knowing what is correct/incorrect first.


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## GrampaDave (Dec 4, 2014)

I will check the temperature rise every now and then.

One can also measure voltage drop. At 40A, 300mV (12W) is high, 100mV (4W) is fine.


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## Jump-start (Sep 26, 2012)

GrampaDave said:


> I will check the temperature rise every now and then.
> 
> One can also measure voltage drop. At 40A, 300mV (12W) is high, 100mV (4W) is fine.


That is good, voltage drop across any given point is almost equivalent to a thermal heat came.


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## mkdm0 (Mar 18, 2016)

GrampaDave said:


> Was it code compliant in 1959 to gang single-pole breakers (no common trip) as double-pole main disconnects? I can't imagine that being permitted today.


It isn't, all 2 and 3 pole breakers have to have a common trip, don't take 2 single pole 30 amp breakers and put a finishing thru the holes in the toggles.

The last thing you want is to be inspector bait!!


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## Jump-start (Sep 26, 2012)

mkdm0 said:


> It isn't, all 2 and 3 pole breakers have to have a common trip,



Not in all cases. A straight 240 volt load does not need internal common trip per code, only listed handle ties. Key is listed as you mention.


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## brric (Mar 5, 2010)

Jump-start said:


> Not in all cases. A straight 240 volt load does not need internal common trip per code, only listed handle ties. Key is listed as you mention.


 All multi-pole breakers are common trip unless specifically labeld "non-common trip". Single pole circuit breakers with handle ties are permitted for 120/240 volt circuits such as MWBC's.

Additionally, single pole breakers with handle ties may or may not trip both breakers upon a fault.

Documentation from Square D. Not sure if you can read it or not.


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## GrampaDave (Dec 4, 2014)

Thanks for the common trip info. I was pretty sure that my 1959 install with indicating-handle-tied single-pole breakers was a cheat.

In other news, five years after my escapade, I exercised the breakers and measured voltage drop again. Voltage with a slash is before/after exercise. Calculated resistance and power is after exercise.

What I really wanted to know is the stab drop but that's not possible with all breakers in place, so instead I just measured from bus to the breaker's load lug. Resistance dropped significantly after exercise, so part of the numbers below is internal to the breaker and not related to my stab contact.

It's looking good.

CIRCUIT MV AMPS MILLIOHMS WATTS

Range 120/95 45 2.1 4.3
Sub A 140/85 35 2.4 2.9
Sub B 60 23 2.6 1.4
1 110 18 6.1 2.0
2 130 14 9.3 1.8
3 130 14 9.3 1.8
4 150/90 15 6.0 1.4
5 150/80 17 4.7 1.4
6 180/100 10 10.0 1.0
7 135 14 9.6 1.9
8 130/80 13 6.2 1.0
10 100 14 7.1 1.4
11 80 14 5.7 1.1
12 90 14 6.4 1.3
13 85 14 6.1 1.2
14 100 14 7.1 1.4


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## GrampaDave (Dec 4, 2014)

I had wondered if I could have used Eaton Type CL breakers to replace my TQL's. Nope, the only GE breaker CL is classified to replace is THQL, and only in modern panels. (TL, TLM, TM; not TRX.) Not real useful since THQL is abundant and cheap.

JFYI,
Dave

I wanted to attach the PDF file from Eaton, but it's a bit too big. I just asked them what CL is classified for, and they emailed me the file.


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## GrampaDave (Dec 4, 2014)

Actual stab drop in circuit 2 (late-production THQL1115) is 5.1mV at 15A, or about 340 micro-ohms, less than 4% of the total bus-to-wire resistance. The rest is inside the breaker, mostly the heating element that effects thermal trip. I removed the opposite-side breaker so I could probe the contact fork.
Measured with a Fluke 8020A set to AC 200mV.


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## surferdude2 (Nov 21, 2019)

That's an interesting tale of adventure into the uncertain fix with possible unintended consequences. It's all still in range of the ordinary safe operating standards so the panel may be as safe as it ever was.

That said, I will add that it's disappointing to see the improvement after exercising the five breakers you listed. Since we can't be sure of the linearity of the time vs. change line, it's possible that all of that change didn't take place at a linear rate. Consider that it may have a cumulative effect and may eventually develop into a more accelerated rate until you become the victim of a thermal runaway that would destroy some things.

I'm just saying that to scare you and put an idea in your head that perhaps you should check it more frequently.

Happy New Year and full speed ahead! I like your style.


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## GrampaDave (Dec 4, 2014)

It is so easy to measure drop across the breaker that there's no excuse not to do it every year. I wanted to see how bad it would get if it were left alone.

The stab contact itself maintained a low resistance that's a negligible part of the total. Most of the heat is generated inside the breaker. It would at worst precipitate a thermal trip. Resetting it would re-seat the circuit interrupting contacts.

I believe that, in day-to-day use, the panel is as safe as ever. The risk is when a tech removes breakers. If both breakers on a stab are pulled, the second one may take the clip* with it, and it could fall onto the bus and arc. I glued them in place, but my private notes include a warning to hold it down with a nonconductive tool. I would have loved to spot-weld them but I don't have the means, and anyway, the bus would be live. Been there done that not gonna do it again. =8)

* A plain brass strip folded over the corrugation to make it resemble GE's new profile.

Thanks for the encouragement.

Dave


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## K_Stock (Feb 27, 2021)

GrampaDave said:


> It is so easy to measure drop across the breaker that there's no excuse not to do it every year. I wanted to see how bad it would get if it were left alone.
> 
> The stab contact itself maintained a low resistance that's a negligible part of the total. Most of the heat is generated inside the breaker. It would at worst precipitate a thermal trip. Resetting it would re-seat the circuit interrupting contacts.
> 
> ...


Dave,

Gluing them in place?

A stern reminder is in order that the things we do today will outlive us. Whether people have hobbies in tinkering in areas like this or not, it does not give people the excuse to perform modifications or make installations that do not abide by the current Codes, no matter the trade or how trivial the work, _even if you are the owner_.

In a situation like this, even if you are comfortable taking this risk on in your life, and even the chance of potentially exposing your community to a hazard via overheated service entrance conductors, what would happen if you were to suffer a death via car accident unexpectedly? - you would not be around to handle these mitigated risks you have taken, and now you have exposed a stranger to a potentially life-threatening situation. 

Let your hobby coincide with safe installations and practices. Leave this world a little better than you found it.


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## afjes2015 (May 21, 2015)

People have to start looking at dates before they reply to a post. Another post brought back from the dead.


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## K_Stock (Feb 27, 2021)

A little more than a year, however the message is still crucial to anyone coming across this thread. 

A person like Dave should seek employment with a testing laboratory in a controlled environment rather than expose real people to dangerous conditions.


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## GrampaDave (Dec 4, 2014)

I'm "following" this thread but I did not get notified about the new posts.
I will replace the panel in the next few years. Besides tampering, it's full and I want to add a couple circuits. (An outdoor 120V receptacle, an individual circuit for the spot water heater, and if I get another car it might be electric needing a charger.) Probably a GE TM3220 since I want to reuse the breakers.


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## seharper (Mar 17, 2020)

Since you've modernized the breakers, the real threat here is the core problem with Rule-of-Six panels. That being the breakers sum up to well over service rating, so nothing prevents you from overloading them. 

You might as well just replace the panel with a meter-main at that point. Or just install a main-breaker panel before this panel. 

Some panels provide a main breaker and 8 breaker spaces, and then "thru lugs" intended to go onward to another full-size panel such as this one. That will get you 8 more spaces and eliminate the safety issue with Rule-of-Six. Now you don't have to rewire any circuits in this panel.


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## GrampaDave (Dec 4, 2014)

Glad to hear from you Mr. Harper.

I wouldn't dream of overloading the service. The existing breakers add up to 240A or 120% of service which complies. My problem is I'm out of slots and no tandems available. (GE Type TR was discontinued 50 years ago.)

The old panel is flush-mount in the common wall between house and garage, with meter pan flush in front of the house a couple feet away, with mast straight up through the roof. There's no room for a meter-main, we are right next to the garage door.

Feed-through main breaker panel sounds... really good! (Sometimes called a trailer panel; not a ranch panel, that's a meter-main-distribution combo.) I see models available from several major mfrs. Looks like the biggest panel with flow through is 8 spaces. Eaton BR816B200RF is 13-1/4" x 24", Siemens is taller. I figure 4/0 AL SEU from the pan to the new panel (same as current construction), and SER from there to the old one. That would support 16 single-pole circuits using tandems. Big safety feature is we can dead everything by throwing main. I'll still lose house power during install but way less than a full swap. Thanks!

Oh-oh, I'll have to unbond neutral and ground at the old panel. Was it just take out a screw back in 1960? GE TRX2820 in case you have an ancient datasheet. I'd look but right now I'm in a cast recovering from surgery.


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## GrampaDave (Dec 4, 2014)

I measured and looked around for a while in the garage, and I decided the feed-through panel is just too awkward to install, I don't really have room to do it clean. After obsessing for an entire day, I think I've come up with a sequence that I can handle, for cutover to a panel swap. I'll do it in spring or fall when we don't need heating or cooling.

The new panel will be a GE TM3220CCU, which has 32 positions, and up to 40 circuits because some rows support THQP. I wanted TM3220C64 (64 circuits) but the box is bigger and it won't fit.

SCRIPT:
Cut out drywall around old panel.
Provision new panel with #10/12/14 cable clamps. (Not SE/6/8.)
Temporarily surface-mount new panel next to old.
Remove dead fronts.
De-energize/disconnect/unclamp nonessential branches and move their breakers.
Connect #6 temp feeder wires to new panel. Hots and neutral.
Turn off 50A Sub-Main B breaker.
Disconnect old Sub-Main B feeder and connect temp feeder.
One by one, disconnect and remove essential cable, move breaker, and extend from old panel to new panel, entering through clamps.
Cover up remaining unused stabs in the new panel.
Turn on Sub-Main B breaker.
Turn off and remove Sub-Main A breaker.
At this point we have essential branches via new panel - 50A max - and range and dryer via old panel.
We can go this way for days if necessary.
ON CUTOVER DAY:
Turn off range, dryer, and Sub-Main B breakers.
Pull meter.
Remove from old panel: SE cable, temp feeder, range and dryer breakers and cables, and Sub-Main B breaker.
Remove empty old panel.
Mount new box.
Insert/clamp/land SE cable.
Inspect, reinstall meter, energize.
Install range and dryer breakers.
Insert/clamp/land range and dryer cables.
Turn on range and dryer breakers.
AFTER CUTOVER:
We can go this way for days if necessary.
One by one, de-energize a branch, remove extension, insert/clamp/land.
Install new drywall.

Have I missed anything?


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## seharper (Mar 17, 2020)

On panel height, forget about using double-stuff breakers as a substitute for adequate spaces. So many circuits need GFCI/AFCI now, and spaces are cheap. If you need more breakers in a given height, look at Square D "QO" or Eaton "CH" which put 40 breakers in the physical spaces everyone else puts 30. 

So you're saying install a new panel _temporarily_ next to the original panel site, and move critical circuits over there? 

Sure, then leave the panel there permanently as a generator subpanel LOL. You could use more spaces anyway... finishing the upgrade with 26/30 spaces used is far from wise. Spaces are cheap and as you say, you have loads of headroom and you're out of spaces. "out of spaces" is easily avoided with expenditure of a very small amount of money. 

At that point, shoot, just feed the new subpanel off the old main, and stop right there, you're done. I seriously doubt the two 8-space "mini-panels" inside the old main really need 50A _each_, so tee them off of one 60A breaker and use the other to feed the new sub. 

"Wow, we're already done". 



When you move the cables from the old panel to the new 2nd panel, those splices need to happen inside an approved enclosure with enough space in it. Its cover must remain accessible without tools, cannot be buried under building finish materials. Frankly I never understood the appeal of finishing utility spaces. It just makes utilities more messy and expensive to maintain. 

I don't see how you plan to transition between a flush mount old (and new???) panel and a surface-mount subpanel. That doesn't make any sense to me. The few times I've tried, it involved supreme jackass code violations, like _leaving the deadfront intentionally off the panel_ (which on a non-bolt-on panel will make the breakers fall out, just to add even further to the fail). So I would flush-mount the second new panel, and hollow out the studs for passage ways for a conduit run between them. If the conduit is over 24" you face circuit limits based on thermal derate (4 circuits per pipe for 10-28A). 



To isolate ground in an old panel, you just need to make sure neutral is on a bar isolated from equipment chassis. Grounds are grounded directly to chassis, and you can retrofit accessory ground bars. 


You need to do it right, though. Otherwise the power company is not going to cooperate on the meter pull, as they will want to see permits pulled for the relevant work. You can't just remove a meter as it has an anti-tamper seal on it. If the power company is unaware of a meter pull, they'll find the broken seal and then go after you for energy theft.


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## GrampaDave (Dec 4, 2014)

Thanks! A lot to think about.

I wouldn't dream of leaving off the dead front! That was Temporary Wiring only. Just during the run up to cutover and the cooldown afterward. I planned to end up with a TM3220 in the exact same spot, mounted and wired the same way, as the old TRX2820.

I wasn't going to use any skinnies myself, just the next owner after I'm dead. If I spread way out, plus add an electric car charger to future-proof, I wind up filling 32 spaces. The next guy can eke out eight more poles if he wants a shop.

On the one hand I'm trying to reuse all those breakers I bought a few years ago, and on the other I'm working by what's available, and on the third I'm going on what fits the space. The only models that do all three are TM3220CCU and TM4020CCU. The latter gives me 40 full-size spaces but no skinnies so it's the same circuit max, plus it's expensive and hard to get right now. ($300+shipping _minimum_ vs $160 and most of the places want like $1000 or "sign up to see the price" which never ends well.) At that price it's a wash between buying all new breakers and buying the expensive panel that takes the current ones. By the way, one of my leads is a $300 TM3220CCUAF9K kit which comes with five 15A CAFCI breakers. I can use four of them and upgrade my safety.

I was only going to surface-mount temporarily, then sink it into the old box's hole during cutover. I was trying to avoid permanent splices. And messing with the meter pan and running new SEU. Am I flinching at a shadow? How hard is fishing 4/0 SEU?

By the way, the reason I ran aground with the trailer panel idea is that the only ones available are outdoor i.e. surface mount, plus they're huge - as bulky as the TM3220 while still only adding eight spaces. A trailer panel plus my old panel is no better than just a TM3220 - they each total 32 full-size positions.

<Wow, we're already done>
But it sounds like you propose to sub the new panel off the old. If I understand you right, we've failed a prime objective: getting a main-breaker service instead of a rule-of-six service. If the old panel stays in the picture, the flow has to be meter to new panel to old panel. And as you say, the old panel has to de-bond neutral and ground. There's no ground bar today. I doubt I can get one.

If I de-bond the old panel, then I suppose I could flush-mount the new panel next to it, run new SEU from meter to the new panel... what's the best way for a novice to splice it?
...And feed say 100A to the old panel, and migrate the old rule-of-six main-bus loads to the new panel. I'll try to determine how bad a new SEU run would be. At best I suppose it's just pulling down a bigger hunk of drywall and boring a couple studs. It depends on what's going on at the meter. If they clamped or stapled in an inaccessible spot it's a deal breaker, I'm not playing in a live socket! I'll ask the POCO about cutting the drop. (They were fine with a DIY panel swap, just pull a permit at City Hall. City Hall was very friendly, inspector said call me anytime ask me anything. They've worked with me before.)


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## GrampaDave (Dec 4, 2014)

I forgot to say. This house is nothing special. It's a 1960 tract house, in a tract house neighborhood. 1600 sq ft including finished basement, electrically heated, 3BR 2BA, 1/4-acre lot. There's not going to be a servants' cottage or carriage house. There's not going to be an addition in my lifetime, or likely ever. Due to shading, PV is not a contender. My old panel is the biggest I've seen around here.

My neutral bar *does *have a bonding screw, see photo, at the center of the vignette. (It has 48 small screws, 5 medium lugs - one with double-stuffed neutral, oops - and one huge lug for the SE neutral.) There is no separate ground bar. There's enough space to add one, but there are no mounting holes. I will ask the AHJ if drilling and tapping holes (10-32) and mounting a modern ground bar is okay. (GE TGK24.) If they say no, this rules out keeping the old panel.

The 100A breaker I mentioned last night (to feed the old panel from the new) is a THQL21100. It's about $50, not bad.
The label does not say how small a wire I can put in the main lugs. There's 4/0 in right now. THQL21100 max is 1/0. Is that likely to pass inspection? What's the proper torque on those old main lugs?

Either way, I'm looking forward to being free of rule-of-six, but I'm in no hurry except with respect to product availability.

Your reminder in other threads that most/all new branch circuits are required to be AFCI and/or GFCI makes me understand why you've begun dismissing tandem/skinny breakers. I didn't get it before. I will stop being satisfied with 32 positions. In GE land, that means subbing the old panel or hunting down a TM4020, oh joy. Or dropping GE and pricing out other brand panels *plus* their breakers, more joy.


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## GrampaDave (Dec 4, 2014)

Bought a TM4020CCU. I'll swap it in this coming spring. This is the 40 full-size slot model. There's also a 40/80 variant.
The panel arrived damaged but I repaired it with inspector approval. It must have been dropped, the plastic mounting feet for the breaker (heavy) end of the bus assembly were cracked. I surrounded them with little cardboard dams which I filled with JB-Weld slow two-part epoxy. I re-drilled the holes after it cured. Now the feet are thicker so I have new longer screws, cushioned by nylon washers. I think it's better than new.

UPDATE: Inspector coming Friday to examine the site pre-work and talk through the plan.

UPDATE 2: Plan A approved with skepticism, plan B approved with enthusiasm. I developed my own misgivings about plan A, so I didn't push back. Rather than a temporary live-front subpanel haywire, I will do a conventional swap, removing less-important circuits beforehand so on day "minus-one", we're basically camping with refrigerator and microwave. On cutover day, all I have to pull and reinstall is those two circuits and the service entrance cable. I can manage that without stressing out. The next day, riding high from successful re-power, I'll have lots of energy to install the rest of the circuits.

UPDATE 3 202111: I have eye surgery coming up, so I will delay the swap until fall.

UPDATE4 20220321: Surgery went great and I will go ahead with the swap this spring when we're using neither heating nor cooling.
I drove in ground bars with a rented 11-pound Demo Hammer and bit, about 10 minutes per bar in wet clay soil, $50 well spent.
Paperwork submitted to get the permit.


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## GrampaDave (Dec 4, 2014)

The project is moving forward. I have a few cables to reroute through new holes in the studs, then I'll be ready to swap panels on May 16, 2022.


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## GrampaDave (Dec 4, 2014)

DONE! Planned for two days power outage, finished in one. I am so tired...
Passed inspection with only one comment*. The POCO truck guys did me a huge favor and crimped a neutral extension I was getting ready to split-bolt. Loaned me a shear too. That gave my gumption the kick it needed to push ahead and get it done.

* The 240V circuits done with /2 NM should have the white wire tape-tagged black. I'm sort of proud that's the worst thing he could find.


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## seharper (Mar 17, 2020)

Congrats! Yeah sorry I dropped the thread last fall. But it's done and behind you and you have a 40-space. Well done! 

Yeah, nobody marks the whites the first time lol.


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## GrampaDave (Dec 4, 2014)

seharper said:


> Congrats! Yeah sorry I dropped the thread last fall. But it's done and behind you and you have a 40-space. Well done!
> 
> Yeah, nobody marks the whites the first time lol.


Whew. And thanks.

Nobody marked those whites back in 1960!


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