[miamicuse]

I had a short, caused by my being galactically stupid stupid stupid, well at least I am still alive.

I thought I had the panel turned off. Well I did. I then turned it back on for a second to open the garage door, then a phone call distracted me, and I forgot to turn it back off, and I proceeded to do stuff as if power was off!!!

I was in the middle of doing some major reorganization and rewiring in this 200A Siemens subpanel. I have added a new 3/4" EMT conduit connection at the bottom of this panel and I was pulling some new THHN conductors from a junction box into the panel. Some bare copper ground conductors got in the way, and I wasn't paying attention as I pulled the new conductors in, they shifted the positions of the bare ground copper conductors and they made contact with the metal bus at the bottom. A loud pop and everything on this side of the house connected to this subpanel went off.

Here you can see a close up where the bare ground conductors (two of them made contact).

Here you can see the lowest part of the bus where there is a metal burnt mark.

Yes I know the wires were all messy and should be neatly tucked away, but they were this way because I untangled them to replace them.

It was scary as it was pretty loud and some sparks.

So now the lower two fins of the bus, they are now damaged? Is it damaged serious enough to cause problems if I ever add more breakers to connect to them? I assume you can't replace a section of the bus you must replace the whole thing?

 

[miamicuse]

every time I get into trouble it's due to some phone call distracting me. Last time it was a pot I had no the stove that I was heating then a phone call and I soon forgot about the pot then went outside to the backyard to mow the lawn for an hour until the smoke alarm went off in the kitchen.

 

[miamicuse]

I do not anticipate to ever need to expand all the way to use up all 40 slots, but never say never. I am on slot 25 now and I have a few unused one above that I have disconnected due to switch some appliances to gas.

But in the event I do need that slot, what would be the remedy? Replace the entire bus? Replace the panel? Or leave that and switch a few slots to use the skinny tandem breakers?

 

[miamicuse]

Messy wires are not bad. What is bad is when your wires are too short to give you freedom to move breakers around,

Those ground wires have lost cross-section and thus are not safe. It looks like those wires are taking the scenic route though, so add a $6 accessory ground bar to this panel, and terminate them there.

Those ground wires were all in the process of getting replaced. That's why they were all untangled. They are no more.

If you are hellbound and determined to get it back, then A) get accessory ground bars for this panel and move all grounds to them. B) have your electrician change your meter pan to a meter-main, so you can do this next part safely, because handling unfused service wires live is out of the question.

I can get this entire panel de-energized including the feeder wires because this is a sub-panel. The main panel is on the other side of this wall, and the feeder wires are connected to the main lugs of the main panel. I can turn the whole house breakers off in the main panel to completely de-energize this panel.

I guess I am going to hold off since I still have 16 empty slots left in this panel and 3 in the main panel.

But now I am thinking may be my stupid accident actually might have caused more damages that meets the eyes. I will describe it in my next post.

 

[miamicuse]

So once the breakers were tripped and I did a hard off and on, everything came back normally, seemingly for a while.

Then all of a sudden, some lights went off. I checked around and it appears I lost half my circuits. Looking at the panel, every other circuits from top to bottom (1, 5, 9, 13...) dead and the other ones (3, 7, 11...) are OK. Looks like I lost one leg of the service?

I waited about 10-15 seconds, everything came back on by itself.

A few hours later, I pressed the push button to operate the garage door opener, and as soon as I pushed it, the house went dark again, and it seems the same circuits are off.

As I mentioned in the original post, this is a subpanel, with the feeder wires coming from the main panel on the other side of this wall. There are no breakers for this sub in the main, the feeder wires are connected to the bottom lugs of the main panel.

So I went to the main panel, and I noticed half the circuits on the main panel are off as well. If I then turn the whole house breakers off and on, it will turn everything back on again.

Since then this has happened twice again. Each time, I was able to restore everything by turning the whole house breakers off and on. I haven't figured out if there is a consistent trigger to this, and it seems very intermitent. The only thing I noticed pushing the garage door button triggered it twice.

Is it possible that this short accident in this sub, actually caused some damage to something to have caused this? Or something is wrong with my service that seems to be coincident with my shorting the panel bus?

Any idea how I would trouble shoot this new issue?

 

[miamicuse]

Interesting. Usually the dead half circuits don't die altogether, they kinda "wheeze". Because the dead phase is connected to the live phase via the 240V loads.

Maybe that's what's causing your intermittent behavior.

To find the problem definitively, shut off every 240V load in the house. Then see if all those wires go stone dead and stay there.

If so, you lost a phase somewhere - sounds like it can only be at the meter or weatherhead or utility pole top. All 3 are the power company's responsibility, however you are responsible for maintenance of the meter pan. It's possible your dead short over-strained a connection that was going to fail anyway in March.

Thank you.

OK I am not quite following the "Then see if all those wires go stone dead and stay there." I don't have that many 240V circuits, since I use gas, so range, dryer, water heater etc...are on gas. The only 240v loads are the pool pump, and the two central AC systems. So I turn off the breakers for those in this subpanel as well as the main panel correct? Then what is the next step? Wait for the problem to happen again, and see if I am still able to restore power to everything by turning the main breakers off and on?

Is this something I should contact the POCO to check? I don't know if they are able to detect any issue with the overhead power lines, I do have a smart meter. However, due to the DIY work I am doing on the panel I am concerned if they want to see this subpanel which is right now a work in progress.

 

[miamicuse]

The next time you lose power, measure with a volt meter at the main breaker before you touch anything else. Measure from line to load on each pole. If it's tripped you will read 120V, if it's still closed you should read 0V.

This will tell you if the main breaker has gone bad. Sometimes they trip internally but the handle doesn't move.

Thank you!

OK just to make sure. Do you mean the breaker for the subpanel where the short happened or the whole house breaker in the main panel?

This is the breaker for the newer subpanel at the top. The one that tripped after the short and I had to push real hard to OFF back to ON.

This is the main panel on the other side of the wall, It has 4 breakers at the top which are the main breakers for the entire house (including main plus two subs).

Since the lost on half the circuits happen on the main panel as well, I am assuming you mean to test it across the main panel breakers line and load. So to make sure I understand fully, this means with my volt meter, when this problem occurs again, I will measure the voltage difference between the RED and YELLOW areas in the following pictures.

If the breakers have tripped are functioning property, I should get 0V. Then the problem is elsewhere. If I get 120V, then there is a problem with the breakers and a replacement is needed.

If the problem is elsewhere, then I will do what seharper suggested, to turn off all 240V loads in main and subs, to see if the half energized circuits are now dead or still alive?

Or should I do the line/load across breakers voltage measurements with all the 240V circuits turned off to ensure there isn't anything crossing over?

 

[miamicuse]

As a really WAG, I'll go with the right hand pole.

OK, I'll do that and report back.

Now, if I am not getting power in one phase due to some intermittent faulty utility connections on one pole, I will also get 0V across the line/load on the breaker regardless if it's open or close because it's 0 in 0 out right?

 

[miamicuse]

Go straight to the main breaker in the main panel. Don't touch anything else. Measure where you have indicated. 120V indicates the breaker is open regardless of handle position. 0V indicates the breaker is still closed and the problem might be in the meter base, or more likely the utility connections.

So far I'm guessing the main breaker as the problem goes away on reset.

Well today for most of the day nothing happened. No loss of power. I was starting to think may be the intermittent issue has gone away....then it happened after dusk. Yesterday also happened after dusk. I am not sure what might have triggered it, more lights came on with more demand?

So I went to the main panel with some of the circuits now off.

The main breakers in the following picture, I put my multimeter and checked voltages on points A B C D.

Between A and B - almost 0, 0.14, 0.13, 0.15 but practically zero.

Between C and D - 120V, again flashing between 118 119 121...

Next I went and turned off all the double pole breakers that are 240V. Repeated the test from A to B, then C to D, same results.

Then I flipped the main breakers OFF then back ON, now all the circuits seem to come back. I then repeated the tests when everything is restored.

Between A and B - again the same, practically zero.

Between C and D - now it is very low, instead of the 120V when I lost the circuits, now it's 2.2, 2.1, 2.4, 2.1...but it doesn't go down to 0.1-0.2 like it is with the other pole.

So does this suggest that the right side of this quad breakers has gone bad?

 

[miamicuse]

If the quad main breakers are the issue here, then I will need to call an electrician to have it replaced as I can't do it myself with that thing always energized. He will need to turn power off at the meter correct?

Does this preclude any utility line issues? No need to call POCO now?

I wonder if this is something caused by my short accident. If that is the case, would the breaker in the subpanel (the one that tripped) where the short happened also be a problem? The main breakers didn't trip that time - or may be it did internally? I have never seen the main breaker trip come to think of it.

 

[miamicuse]

Strange...today everything seems to be working, power was normal. I had the pool pump (240v) running, then I lowered the thermostat to 72 degrees (outside temp is 75 my thermostat was 78) so force the central AC to turn on to stress the system, turned all lights on inside the house during the day, and nothing tripped. Strange.

Tomorrow I will call an electrician to come replace the main breakers. He can turn off power at the meter right? Or this will require POCO to come pull the meter?

 

[miamicuse]

Wait a minute.....there should be no potential between A to B or C to D. Those points are in line....no potential. OP should be reading volts between A to C to get 240v or B to D to get 240v.
He should also test each point to the neutral to get 120v each.

The reading he had of 118esh from C to D might indicate a short downstream on that phase. I think the breaker is doing its job and replacing it will not correct the problem.

I agree that it should be 0v between points A & B, and points C & D, but with one leg lost power, and C & D has 118v, doesn't it mean the contacts between C & D is open which is a problem as the handle is still in the ON position?

If I have a short downstream, well I did have a short when the bare copper touched the bus.

As to measuring between A to C or B to D, I thought about doing so, but then I wasn't sure what would happen when connect A to C, wouldn't that send power of the same leg down to D so both sides now will have the same leg? I didn't know if that would cause any harm so I didn't try.

If I do have a short downstream still, how can I check for it? May be I can check it once the breakers are replaced.

 

[miamicuse]

Some new development. I called an electrician to come replace the main breakers, but let's hold off on this and let me provide more updated information.

First of all, nothing happened yesterday the entire day and night, no loss of power. So the loss of power does not always happen at dusk, and I still don't know what triggers it. As I stated I try to power up as many things as possible to try to replicate the issue including pool pump, both central AC units, shop vac, window AC, all lights. No problem. Then I turned everything off, and a few hours later, it happened again. I lost one leg of my power.

So I took out of multimeter and did more measurements while the main breaker handle was still in the ON position.

As I stated last time I measured voltage differences:

Between A & B: almost zero
Between C & D: about 120v.

This time I took additional measurements:

Between A & neutral: 120v but it fluctuates.
Between B & neutral: 120v
Between C & neutral: 120v
Between D & neutral: around 4.12v

and if I flip off all the 240v breakers the results are the same.

then it gets better, see next post.

 

[miamicuse]

So while I had the dead front opened again, I decided to take a closer look all around inside the panel with a flash light, and paying extra attention to the right side of the main breakers. I noticed something.

Do you see it? Just to the right of the main breakers, is a electrocuted dead lizard.

I wonder if that could be what's been causing my problem? I used a plastic stick and flicked it out of the way, turned the main breakers off and back on, and it was fine for a few more hours until it happened again. So now I know the lizard was not the cause.

At that point I called the electrician.

 

[miamicuse]

The electrician asked me to send photos of the main breakers. Two hours later he arrived but he said they do not have my 200A main breakers in stock, but he got a new set of Siemen's breakers and he will try it.

So he pulled the meter, then removed my existing breakers. The new breakers (it is a wider breaker with one single switch) did not fit, too wide. So we are back to looking for the old breakers. He told me they are no longer manufacturing old style breakers due to COVID, and if I want to find a matching one I will have to search online for one.

When he put the old breakers back on, he said that my lugs are a bit corroded and he dared not put the proper torque on them fearing they may break. He will search for a set of breakers matching what I need then come back next week.

An hour later he said they are selling my breakers on ebay, a used refurbished one is $200, there is a new one for $400+. He said he can actually order a new panel for $450+ and use the same guts in that panel to swap mine out, new breakers new bus new lugs the only thing old will be the enclosure. He could do that in one day that way I can use the new updated breakers and everything is new inside for probably $850-950 labor included.

Does this sound reasonable?

 

[miamicuse]

It sounds like you're way ahead of this, but just for the record...

If you are testing for "a lost phase", then turning off all 240V loads will result in all the 120V loads on the lost phase going immediately dead. They will no longer be being held up by cross-connection through the 240V loads.

If the loss of phase is intermittent, then the 120V load loss will also be intermittent during this test.

It is intermittent in that I cannot tell what triggers it. Once it happens it seems to always be resolved temporarily by reseting the main panel whole house breakers. Then it may stay fine for 2 hours or 2 days.

I am curious, if I have a 240v device running , say a swimming pool pump, if I lose one leg, what will the pool pump do? Will it burnt up or will it just quit?

 

[miamicuse]

I wouldn't use a used refurbished breaker unless there is no other choice. If the price is less than 1K, that is pretty good, and you have piece of mind that you have new breakers.

Yes I am going forward with getting the guts inside that main panel totally replaced.

The lizard didn't get electrocuted from touching the hot leg while sitting on that plastic insulator.

$950 is reasonable for that job in my opinion.

If you lose 1 leg there is absolutely no way you can say what will happen with certainty. The 240volt devices are still connected through the other circuits through a new and strange series/parallel configuration. The results cannot be even guessed at unless you map out every load in the house. So far the load distribution in your panel seems to be in your favour though.

So how did the lizard die? It's head was completely missing I thought it must have gotten BBQed from getting near the bus.

I am going forward with the electrician getting a panel that matches mine and swapping out the guts. However he said it comes with new main breaker with a single switch (instead of the one bar across 4 handles). But now I am wondering if I should just replace the whole panel including the enclosure...but there are multiple conduits connected to it if he needs to pull back all those wires it will add a lot more work. Decisions decisions.

 

[miamicuse]

Well as OP measured, there was 120V between C and D. If the break point was where the bus attached to the breaker, then the lizard could've gotten across it.

Yeah, the manufacturers put many panels in a few "box sizes". If you can identify the box size, and find another panel with that same box size, then yeah.

Just, I'm really, really surprised to hear of that working on a panel that old. Either Siemens hasn't changed their box sizes for 50 years (possible), or your guy found a new-old-stock panel of that vintage.

I asked him if he is getting the box with the same exact guts with the same exact main breakers, he said it will be a different type of main breakers with only one switch, So I am not sure what exactly he is planning. If he is just getting a new panel with a new gut and trying to retrofit that into my old enclosure resulting in a hodge podge this would be a bad idea even if the gut physically match right?

 

[miamicuse]

Assuming your guy is doing this right, the main breaker won't matter. He's getting an entire panel - box, guts and cover. The guts and cover will be fitted onto your box.

Well this didn't come out the way I want to.

The electrician came this morning and right off the bet I noticed the panel he has is not the same as the one I have, same width but much shorter in height. So I asked him if the box are not the same the guts will not be the same, and the new dead front can't be used, and the old one will not be in alignment. He said don't worry it will fit we do this all the time. I had to go to work (in retrospect I should have taken a day off but I couldn't work from home due to power will be out all day so no internet I had to run into the office). Around 2pm I called and ask how it's going and the reply was everything is smooth sailing and they are moving along fine.

I left work a little early to check on them and they were just finishing up. As expected the new dead front is too short, the old dead front they had cut and modified to fit the new guts.

This was what I had.

This is what they end up with.

My original dead front slots have been cut lower. I tried to remove it and it won't even remove without turning the upper right breaker off because it's so tight. The original quad breaker spot is now a much wider single switch breaker and they covered the extra space with two 4x4 blanks. There is an uneven slot at the bottom of the main breakers about half an inch tall.

The "new" inside.

If you are curious, yes I paid him, he put in the time but it's a hack I am not happy with. This all started with a set of bad breakers leading to "the guts are loose and not in the greatest shape so let's replace the guts" to "the guts don't fit the dead front so let's modify the dead front". Wasted time and wasted money.

So now I need to figure out a way to undo this, and I know this is irreversible. What are my options?

Do I try to find an used or new old stock of this enclosure and hire another electrician to install a compatible guts with a new dead front?

If that fails then I have to change out the entire enclosure right?

 

[miamicuse]

I think the guy earnestly meant to give you a bargain, given the ugly alternatives. And that is a bargain.

Yeah if you can find a panel with that exact same box, I'd do that.

Otherwise, the pop riveting of 2 junction box lids to cover the panel hole is the hokiest thing I've ever seen and screams "NEC 110.12". I'd get a 10" wide piece of that gauge steel and do a more proper job of it, use the same rivet holes so you don't leave glaring unused rivet holes.

Thank you seharper. I am scratching my head on a long term solution about this, because this is not going to fly if I ever need to have this inspected in the future, either when I need to pull an electric permit, or when I need to change insurance for the house which requires a new 4 point inspection report (plumbing electric roof HVAC).

Seems this thread is running out of steam as the issue kept evolving from one to another. I am going to start a new thread to discuss this latest issue here:

Started off needing a new main breaker, ended up with a...

Recently I had an accident in my garage where I caused a short at a subpanel. Ever since that happened I have been losing a leg of my service at the main panel. Turned out it was a set of bad main breakers. I called my electrician and asked about replacing the main breakers which is a set of...

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