# Drawout breaker racking rules



## drsparky (Nov 13, 2008)

Mbit said:


> Just got into a bit of a heated discussion.
> 
> I said I will not manually rack a 1600A cutler-Hammer DSII of the main switchgear with zero PPE on while the bus is live. I pointed to the arc flash study sticker on the door that said "Shall not be opened while energized".
> 
> ...


hell no.


----------



## drsparky (Nov 13, 2008)

Do a You Tube search for "Breaker Racing Explosion", you will find your answer.


----------



## backstay (Feb 3, 2011)

Back in the day(1990s) I would rack in and out our 2000 amp 6600 volt breakers almost once a week. That had to be done with the doors open, live of course. The only protection was leather gloves. Closer to 2000 we got a blue suit to wear, but it wouldn’t save you from death, just the burning part. These were the breakers that tied the turbines or turbine busses to the other busses in the mill. Was it safe? No, but in all the years(over 100) there was never an issue in this mill.


----------



## Mbit (Feb 28, 2020)

drsparky said:


> Do a You Tube search for "Breaker Racing Explosion", you will find your answer.


 Yes sir I just got done sending like 5 good ones I found on YouTube to the engineer who backed me up when we were talking to the boss. I was just scrolling Instagram last night and saw a guy who had all his PPE on and still had to get grafts. He was a splicer down in a manhole.


----------



## u2slow (Jan 2, 2014)

Racking-out breakers on a live switchboard used to happen on our ships (not with me around) but that stopped, thankfully, about 10 years ago. 

The pendulum has swung far though.... Now there's "high voltage' stickers on everything (120-600v) and the lockout procedures are more difficult to follow correctly than the cobbled-up circuit you're trying to troubleshoot.


----------



## Mbit (Feb 28, 2020)

u2slow said:


> Racking-out breakers on a live switchboard used to happen on our ships (not with me around) but that stopped, thankfully, about 10 years ago.
> 
> The pendulum has swung far though.... Now there's "high voltage' stickers on everything (120-600v) and the lockout procedures are more difficult to follow correctly than the cobbled-up circuit you're trying to troubleshoot.


Yeah I hear what you're saying. I've worked in data centers where the procedures were borderline ridiculous. Although it had very little to do with safety. All about down time. They said it was $1,000,000 per minute if they went down hard.


----------



## Mbit (Feb 28, 2020)

This whole thing is because they don't want to shut down one of the generators for the 5 minutes it would take to rack it off. Another 5 when we're done with the work we need to do. They're scared shitless of the office.


----------



## Southeast Power (Jan 18, 2009)

The sad thing, we just didn't have the information available or the implied authority to do anything about it. 
It was SOP to drink a beer to calm your nerves before drilling a hole in an energized bus bar using a corded drill that was "double insulated".
Now we wear proper PPE, use the correct tools, lockout tag out, and have a full habited Nun say a Rosery before we start.


----------



## Mbit (Feb 28, 2020)

Southeast Power said:


> The sad thing, we just didn't have the information available or the implied authority to do anything about it.
> It was SOP to drink a beer to calm your nerves before drilling a hole in an energized bus bar using a corded drill that was "double insulated".
> Now we wear proper PPE, use the correct tools, lockout tag out, and have a full habited Nun say a Rosery before we start.


Yeah man that's pretty crazy looking at from today's perspective.


----------



## paulengr (Oct 8, 2017)

Racking off…show me a case where this has ever resulted in a problem.

Racking on with SOME designs I can understand. They have these ridiculously long bus bars sticking out and all racking mechanisms have some serious torque in order to force the fingers onto the bus. It is possible to force one bus bar into the other while racking a breaker onto the bus. In fact 99% of the problems I’ve ever had have to do with alignment issues. No matter what it looks like you have a large flimsy box holding bus bars that can easily be twisted, not level, or any number of structural issues. The breaker itself on some designs just sort of rolls ir flops around with little to no guide rails or anything to ensure it will engage the twisted mess if a cell. Trouble is that even if you take measurements like checking diagonals and take every possible step to visually verify every so often you run into one that gets stuck. There is a lot of pressure to get it in as quickly as possible and that’s when desperation and forcing things happens at a time when this is not what you should be doing. Been there, done that.

Second issue is that although manufacturers take all kinds of steps to try to ensure the breaker is open when it engages the cell, unless the user visually or electrically verifies, it’s still possible. One of the more famous arc flash videos from Colombia as I understand it the breaker was exposed to salt spray for weeks so it was in no way insulated no matter whether it was open or not. Again some basic checks like Megger line to load just to verify go a long way.

In every failure out there it’s a combination of things. Some designs are inherently more dangerous than others. If you look and the breaker arms are shorter than half the phase spacing or slide into tubes that separate them with insulation barriers it’s a good sign. Doing that extra step to check if it’s open and not relying on the indicators and stopping and rechecking or restarting if you feel stiffness makes all the difference in the world. I’ve worked with some absolutely atrocious equipment and not had failures on draw out mechanisms.

If you take the time to evaluate your situation and not just take the advice of a standards committee that is made up mostly of equipment manufacturers and safety consultants neither with real world experience you’d be far better off.

Still there are some serious issues. The failure rates of bolt in breakers are vastly less. Wonder why? Plus things get real fun when the failure isn’t the breaker itself, which is kind of the problem with draw out cassettes. The cost is also about half or less. And if you aren’t going to rack in/out live then you just killed 99% of the justification. The only remaining issue is that panelboards and the line are UL 489…rated for 3 cycles to destruction compared to 30 cycles for drawouts…UL 1077. There is real value there, but the draw put feature is highly over-rated.


----------



## Mbit (Feb 28, 2020)

Yeah I've racked 25 or 50 in a day doing shutdowns at the testing company well aware of the things that can go wrong with them. Done quite few callouts to fix various faults in switchgear so it's not like I'm some house roper blundering through this.
I get paid by the hour not by production, so I don't care if we lose an hour of production. Or if they fire me lol. These breakers may be inherently safe but people have died racking in breakers without proper PPE.
I'm basically the only guy here who even knows how to use a multimeter so sometimes I just need a sounding board. If I wanted to talk to a bunch of NEC dorks I could go on mike holt


----------



## SWDweller (Dec 9, 2020)

to the OP's statement. 
.
That tag means do not open the exterior door when the breaker is closed latched on the bus. MFG speak for we aint responsible for idiots. So using the controls on the exterior of said door open the breaker and then you can open the door. Eventually someone will install solinoids on the doors so if the breaker is closed you can not open the door anyway.

I have not done DS in a long time. I worked for Eaton and am intimate with the breakers. I do believe that there is a safety wired into the breakers, on the MOC and TOC switches. 
This prevents the breaker from being closed and removed or installed on the powered bus.
I do know there are 3 positions for the breaker, closed on the bus, test and disconnected.
Remembering if you try and use the racking equipment the safety's will trip the breaker free just before it disconnects. Which could be very bad. 

What I find appalling is you are working around 1600 amps and your not wearing any PPE. 
What no one depends on you? FR underwear is not all that expensive. When washed with care I have some Carhart undershirts that are close to 15 years old. I get the concept where the company pays for uniforms. Still you can increase your chances by getting some under butt ware on your own. Electrical Hazard boots are a good place to start.


----------



## paulengr (Oct 8, 2017)

To be clear here the dangerous failure rates on circuit breakers are about one in a million for draw outs on average. And that’s only when the mechanism is being operated. You are far more likely to die in a fatal auto accident on the way to work for instance. “One in a million” is relatively speaking about the average for a fatal accident of any kind for most occupations. The equipment is NOT inherently dangerous. Even the clowns on the 70E Committee admit that. And just walking by isn’t very risky nor is just operating it (trip/close) IF it’s in good condition.

But if you were going to remove a breaker that had not been serviced in 5+ years, or it was rusted through, or coated in wet sawdust, or it had just tripped and you can’t find a reason, or there are a bunch of black soot marks around it, chances are that “1 in a million” AVERAGE may be your unlucky day.

At some point we have to accept the fact that life has inherent risks. If you are just walking from your vehicle to the office you could be struck by a meteor and killed. But the chance of that happening is so low that we treat it as an acceptable risk. In fact we do this with just about anything that falls under the “typical day at the office” threshold…1 in a million. There is some variability here…say cashier at a grocery store vs. saw mills, but overall that’s what happens. We don’t make cashiers dress in bullet proof vests even though there is an “elevated” risk. We take what society calls “reasonable” precautions.

With that in mind a breaker is a big spring loaded switch that opens electrical contacts. The thermal energy released in a contact is proportional to the current squared times the resistance. When contacts are closed the resistance SHOULD be very low, under 1 milliohm,, so very little thermal energy is released. With open contacts Ohms law applies and with millions of ohms, current is very limited and again no thermal energy is released. In between those two conditions is when things get very ugly, very quickly. So we need to transition as fast as possible. I don’t know the timing on DS breakers in particular but at that time 5 cycles, about 0.08 seconds was pretty common. This is far faster than you can do by hand. In fact ALL breakers, even the dinky 15 A ones use some kind of mechanical aid like an overhung cam to control the process. Obviously anything that threatens this process can be very bad. Uncontrolled connections are one case. Closing by hand onto a load would be another. And with the breaker itself mechanically most are greased with Mobil 28 which is an oil mixed with a clay thickener. The oil eventually evaporated leaving just sticky clay. Plus if you have a bearing under load long enough no matter how thick the grease is it will push it out of the joint leaving direct metal on metal contact. The operating life of even the most active breakers at a whopping 0.08 seconds per motion even a few times per day adds up to maybe a couple minutes over its entire life. Seizing up is also a very common issue, although DS breakers are pretty hardy.

Finally I will just say that I’ve never known any breaker to have some kind of tell tale sign that something isn’t right. They always let you know in some way. I’ve tested thousands of breakers though and seen plenty of failures on the bench. You can always tell when something isn’t right.

That being said there is elevated risk in some activities and racking breakers into a cell is one of them. This is NOT closing a breaker. Many people incorrectly say “racking” when they mean operating. Racking means you roll/slide/jack a breaker into place then using some kind of screw or gear mechanism that squeezes the breaker onto the bus bars forcing the spring loaded fingers open. So you take reasonable precautions doing this on energized bus. Make sure the breaker is open, the load is off, etc. And if it’s possible de-energize the bus. This may mean odd schedules or working things out with the utility…so be it. If not look at PPE options. I can almost guarantee with a 1600 A old DS breaker though you can’t find a cal rating high enough.


----------



## joe-nwt (Mar 28, 2019)

When your time is up, it's up.








Falling helicopter killed student from Kenya


Isaiah Otieno stood out from the crowd.




www.thestar.com


----------



## Mbit (Feb 28, 2020)

Come on bro, this whole thread is about me saying no. My boss is not happy with me right now lol.



SWDweller said:


> What I find appalling is you are working around 1600 amps and your not wearing any PPE.
> What no one depends on you?





Mbit said:


> Just got into a bit of a heated discussion.
> 
> I said I will not manually rack a 1600A cutler-Hammer DSII off the main switchgear with zero PPE on while the bus is live. I pointed to the arc flash study sticker on the door that said "Shall not be opened while energized.


----------



## SWDweller (Dec 9, 2020)

I worked for a place with Allis Chalmers, 7.2kv switch gear. The stuff was old and broken, but still in service. One breaker that we had to work on the feeder load once a year would not rack off the bus. KNOWN by management. So the procedure was to put on a 40 cal blast suit. To operate the breaker. Could not lock it off either. I got assigned the task, always had my suit with me (furnished by employer) went and looked at the arc fault level, 234 cal. I refused. The boss gave me all sorts of bull and we ended up in HR. Where after we got to the head dude I won. All of the cronies sided with my boss and his inability to see the sense of opening a broken 50 year old breaker was a bad idea. 

I get your pain. I ended up leaving under my own steam because of the constant nonsense. Which for the men who lived in the area did not see a problem with doing the work. 
We had a death on the property during one of my "being in charge shifts". Death was not electrically related and I told to talk to a lot of suits. Management took over and my boss was removed from my chain of command. I answered all of the questions truthfully. They knew I would. Lots of changes in procedures after that. Still a very dangerous place to work.

Maybe you should consider leaving, while you can. In my experence trying to change the old guard is a waste of time.

Maybe you should consider leaving while your able.


----------



## mayanees (Jan 12, 2009)

Drawout breaker racking rules:

NFPA 70E has table 130.5(C) titled "Estimate of the Likelihood of Occurrence of an Arc Flash Incident for ac and dc systems". The table is supposed to be used to evaluate whether an arc flash is likely when performing different tasks, so it's a PPE use or not use table.

The 2nd paragraph or section shows the task of "Insertion or removal (racking) of circuit breakers (CBs) or starters from cubicles, doors open or closed." For this task it describes the condition as Any, and the result is that an arc flash is likely, so according to 70E, this is a task that requires use of PPE to the level of the situation. So whatever arc flash label you have listed, that's the level of PPE that should be worn when racking in a breaker to an energized bus. Unfortunately the book version doesn't show the equipment condition as "Normal" or the likelihood of occurrence as "Yes". It shows "Any" and Yes to an arc flash incident is likely..

Further down in the table is the same task but for arc-resistant gear. It's also missing the equipment condition note as "Normal" and the likelihood of occurrence of "No", in the book and for the NFPA Link version.

I attended a 16-hour virtual class conducted by NFPA on 70E and if not for that I wouldn't know of the mistakes with the table. But suffice to say that the intent is that you're supposed to be able to rack in a breaker on an energized system without PPE when it's arc-resistant gear.

So you're in agreement with 70E to refuse to rack in a breaker without wearing PPE on a non-arc resistant piece of gear.


----------



## backstay (Feb 3, 2011)

I worked at a place that the head of maintenance wanted us to go inside the 14,400 incoming transformer enclosure with a vacuum and clean the dust off. We had a meeting when I refused to allow anyone to enter it. I showed up with the manufacturer’s installation and maintenance manual. I won, told my boss later I was prepared to resort to violence. At one point the head shed said we couldn’t afford to shut half the mill down for four hours to do this. I responded that at least we know what value he placed on an electrician’s life.


----------



## Mbit (Feb 28, 2020)




----------



## backstay (Feb 3, 2011)

Taking a trip?


----------



## Mbit (Feb 28, 2020)

backstay said:


> Taking a trip?


Yes sir, today is my last day. Good job, good dudes but time for me to move on.


----------



## backstay (Feb 3, 2011)

I thought you were on a boat? Walking the plank?


----------



## Quickservice (Apr 23, 2020)

Southeast Power said:


> The sad thing, we just didn't have the information available or the implied authority to do anything about it.
> It was SOP to drink a beer to calm your nerves before drilling a hole in an energized bus bar using a corded drill that was "double insulated".
> Now we wear proper PPE, use the correct tools, lockout tag out, and have a full habited Nun say a Rosery before we start.


We did the same thing years ago and really didn't think much about it, until years later when a safety guy showed us a video of three men getting horribly burned. Gives me the creeps to think about unracking live now.


----------



## Mbit (Feb 28, 2020)

SWDweller said:


> I worked for a place with Allis Chalmers, 7.2kv switch gear. The stuff was old and broken, but still in service. One breaker that we had to work on the feeder load once a year would not rack off the bus. KNOWN by management. So the procedure was to put on a 40 cal blast suit. To operate the breaker. Could not lock it off either. I got assigned the task, always had my suit with me (furnished by employer) went and looked at the arc fault level, 234 cal. I refused. The boss gave me all sorts of bull and we ended up in HR. Where after we got to the head dude I won. All of the cronies sided with my boss and his inability to see the sense of opening a broken 50 year old breaker was a bad idea.
> 
> I get your pain. I ended up leaving under my own steam because of the constant nonsense. Which for the men who lived in the area did not see a problem with doing the work.
> We had a death on the property during one of my "being in charge shifts". Death was not electrically related and I told to talk to a lot of suits. Management took over and my boss was removed from my chain of command. I answered all of the questions truthfully. They knew I would. Lots of changes in procedures after that. Still a very dangerous place to work.
> ...


Well as far as I know there's no problems. It's 40+ year old fpe gear. I've never seen inside the cubicle to see how well the retrofit was done. I'm not an expert in how to bend bus and do retrofit type stuff. But this place is very bad as far as overall material condition. The maintenance on the gear is not good but it's not in a bad environment. Still the salt air here slowly eats everything. 
They refuse to exercise the FPE breakers in the main switchgear. When I told my other boss we need to exercise all the breakers a couple years ago he said no because sometimes they "won't work right" or some bs. 
He said "we'll just have a fire and we'll put it out.


----------



## Mbit (Feb 28, 2020)

backstay said:


> I thought you were on a boat? Walking the plank?


I call it a boat which is a bad habit technically it's a ship.


----------



## backstay (Feb 3, 2011)

And the plank? Or are they keelhauling you?


----------



## Mbit (Feb 28, 2020)

SWDweller said:


> I got assigned the task, always had my suit with me (furnished by employer) went and looked at the arc fault level, 234 cal. I refused.


Yeah I hear that, I believe the main swbd energy is 250 or 280ish. Obviously we'll past 40 so I said no. The other electricians are very old school. They'll go elbow deep inside the gear so the bosses idea of what is normal is way off. I sound like a safety maniac to them.


----------



## Mbit (Feb 28, 2020)

backstay said:


> And the plank? Or are they keelhauling you?


Thankfully no keelhauling. I think right now management is more likely to get keelhauled haha. Get off the big boat to a smaller boat, aka crew boat, and ride it in. This thing runs 24/7. I'll send a pic


----------



## Almost Retired (Sep 14, 2021)

Mbit said:


> Thankfully no keelhauling. I think right now management is more likely to get keelhauled haha. Get off the big boat to a smaller boat, aka crew boat, and ride it in. This thing runs 24/7. I'll send a pic


is it an ice breaker ?


----------



## poncho144 (Apr 7, 2018)

Mbit said:


> Just got into a bit of a heated discussion.
> 
> I said I will not manually rack a 1600A cutler-Hammer DSII off the main switchgear with zero PPE on while the bus is live. I pointed to the arc flash study sticker on the door that said "Shall not be opened while energized".
> 
> ...


Yep, management is always putt'n the $ bottom line in Operations above Safety. I could lament many similar SITREPS on this from 1/2 century of Power Plant drudgery. Keep the faith and just do not let 'em git by wit SAFETY short cuts. Hold their patent leather feet to da fire. IBEW all they way!


----------



## MikeWhitfield (Aug 1, 2011)

Mbit said:


> Well as far as I know there's no problems. It's 40+ year old fpe gear. I've never seen inside the cubicle to see how well the retrofit was done. I'm not an expert in how to bend bus and do retrofit type stuff. But this place is very bad as far as overall material condition. The maintenance on the gear is not good but it's not in a bad environment. Still the salt air here slowly eats everything.
> They refuse to exercise the FPE breakers in the main switchgear. When I told my other boss we need to exercise all the breakers a couple years ago he said no because sometimes they "won't work right" or some bs.
> He said "we'll just have a fire and we'll put it out.


"We'll just have a fire" is apparently a much bigger deal to those at risk of being the thing on fire.


----------



## ComTowerSparky (May 28, 2021)

Mbit said:


> Just got into a bit of a heated discussion.
> 
> I said I will not manually rack a 1600A cutler-Hammer DSII off the main switchgear with zero PPE on while the bus is live. I pointed to the arc flash study sticker on the door that said "Shall not be opened while energized".
> 
> ...


I'm with you on that Mbit,I would have made the same call.


----------



## retcec (Oct 3, 2018)

Mbit said:


> Just got into a bit of a heated discussion.
> 
> I said I will not manually rack a 1600A cutler-Hammer DSII off the main switchgear with zero PPE on while the bus is live. I pointed to the arc flash study sticker on the door that said "Shall not be opened while energized".
> 
> ...


You should call OSHA about the unsafe condition your employer wants you to be in. If they were to fire you for calling OSHA you can seek protection under the Whistle-blower Protection in the OSH Act of 1970.


----------



## Toxicnut (Nov 25, 2013)

Nobody will look out for your safety better than you. You make the call. That’s good enough. Anyplace that wants you to do something unsafe, is not worth working at.[/QUOTE]


----------



## MikeWhitfield (Aug 1, 2011)

Way I see it, any manager who wants you to open a piece of gear clearly marked "Shall not be opened while energized" has volunteered to stand in front of you while you do it. Without PPE, to show you how safe it is. 

Virtually every situation that has killed an electrician has been survived by another electrician before you. Most tradesmen are far too smart to do the things guaranteed to kill them, it's the things that probably won't kill you that end up eventually killing you. Every situation that can potentially kill you should have a rigorous analysis to determine whether it HAS to be done hot; usually the answer will be "well, no, but . . ." Things that have to be done hot should have procedures worked out and specialized gear developed to maximize safety; things that don't have to be done hot shouldn't be. I agree with Mike Rowe that safety shouldn't be job one, but it should always be considered. What do we need to do, then how can we do it safely, then how can we do it for the least total cost/disruption. People who neglect the second step are invariably not the people actually doing the work.


----------



## Almost Retired (Sep 14, 2021)

MikeWhitfield said:


> Way I see it, any manager who wants you to open a piece of gear clearly marked "Shall not be opened while energized" has volunteered to stand in front of you while you do it. Without PPE, to show you how safe it is.
> 
> People who neglect the second step are invariably not the people actually doing the work.


^^^^ THIS


----------



## SPINA ELECTRIC (Dec 1, 2009)

Mbit said:


> Just got into a bit of a heated discussion.
> 
> I said I will not manually rack a 1600A cutler-Hammer DSII off the main switchgear with zero PPE on while the bus is live. I pointed to the arc flash study sticker on the door that said "Shall not be opened while energized".
> 
> ...


You did the right thing some companies try to get away with this crap until there is a fatality.Shut it off lock it out and suit up.Good for you.


----------



## Flekota (Mar 18, 2017)

Mbit said:


> Just got into a bit of a heated discussion.
> 
> I said I will not manually rack a 1600A cutler-Hammer DSII off the main switchgear with zero PPE on while the bus is live. I pointed to the arc flash study sticker on the door that said "Shall not be opened while energized".
> 
> ...


Back in the day they didn't have the amperage you do now I'm retired and I sure wouldn't do it what ever OSHA say that's the minimum and they say PPE must be worn tell him he better have the best dam Lawer in the world and he will still lose. in the last 10 year OSHA has gotten very strong in enforcement. Well even the President thought he ccould get them to enforce rules he couldn't


----------



## VELOCI3 (Aug 15, 2019)

Mbit said:


> Come on bro, this whole thread is about me saying no. My boss is not happy with me right now lol.


So give him the suit and the racking device. 


Sent from my iPad using Tapatalk


----------



## Mbit (Feb 28, 2020)

No suit available. And I did suggest that lol.


----------



## backstay (Feb 3, 2011)

Mbit said:


> No suit available. And I did suggest that lol.


Have you “landed” somewhere yet?


----------



## Mbit (Feb 28, 2020)

backstay said:


> Have you “landed” somewhere yet?


Had a couple offers. 

Just got back from an interview. For a job where I'm home every night. I brought in my laptop with pictures of some of the work I do out on the boats. Showed him some pics and explained what I'm doing so he could get a feel for my knowledge level. Resumes are BS and I like to talk shop with people in these situations, helps me guage them and they can do the same. Maybe 3-4 minutes.

I shut the laptop and he says "Those were some nice pictures but they could have been your friend's work and you just stood there for the photo!" 🤣🤣🤣


----------



## Almost Retired (Sep 14, 2021)

Mbit said:


> Had a couple offers.
> 
> Just got back from an interview. For a job where I'm home every night. I brought in my laptop with pictures of some of the work I do out on the boats. Showed him some pics and explained what I'm doing so he could get a feel for my knowledge level. Resumes are BS and I like to talk shop with people in these situations, helps me guage them and they can do the same. Maybe 3-4 minutes.
> 
> I shut the laptop and he says "Those were some nice pictures but they could have been your friend's work and you just stood there for the photo!" 🤣🤣🤣


where is elvis when you need him ???
"suspicious minds"
i doubt i want to work for him just because of that


----------



## Mbit (Feb 28, 2020)

Almost Retired said:


> where is elvis when you need him ???
> "suspicious minds"
> i doubt i want to work for him just because of that


Dude I know I thought we were meshing then he threw that out, hmmmmmm.


----------



## paulengr (Oct 8, 2017)

Flekota said:


> Back in the day they didn't have the amperage you do now I'm retired and I sure wouldn't do it what ever OSHA say that's the minimum and they say PPE must be worn tell him he better have the best dam Lawer in the world and he will still lose. in the last 10 year OSHA has gotten very strong in enforcement. Well even the President thought he ccould get them to enforce rules he couldn't


Uhh no. I’ve seen 3000-5000 A FPE and Westinghouse panels from the 1950s and 1960s. High amperage circuit breakers were mostly oil filled or large air breakers for higher voltages. There is the Magnum DS, aka “Sherman Tank” for instance. Lots of Westinghouse breakers with huge arc chutes. 2300 was popular because large starters were a problem until vacuum interrupters changed everything in the 1970s.

At that time the big design issue was AIC. You didn’t want short circuit current getting so high that you had to use secondary fuses if possible. The current limiting loops we use today weren’t invented yet so current limiting fuses or reactors were the only way to go. Again things changed dramatically in the 1970s. At that time relaying was all induction disc and we set the time delays between relays at around 0.3 seconds so distribution breakers were getting close to the 30 cycle limit in draw out gear. We always designed for a theoretical maximum AIC using the ANSI method which makes it possible to estimate fairly accurately with the calculator of choice at the time, a slide rule. Just showing my age I learned how to use one in 1980 in fifth grade. We had calculators…it was more about teaching how to estimate than the actual skill.

Once the 1990s came along we had the ability to estimate arc flash. Now we started to become much more concerned with tripping on the lowest fault current, not the highest. A curious thing happens with breakers. Lower fault currents increase tripping time BUT with standard time-current curves the arc flash energy increases of fault current is lower. And the trip settings need to be lower, often half as much as in the past. The result is that even with the fastest technologies at 1500 kVA (1800 A) with a 480 V system arc flash is just barely survivable. This has actually driven many plants towards more, smaller equipment and gotten away from the huge switchgear. That and a growing realization that draw out gear doesn’t help you with many of the problems that can and do occur, that bolted gear with its higher reliability requirements does good enough for most uses. So there is a tendency towards more, smaller subs in newer designs that are designed with arcing faults in mind.


----------



## splatz (May 23, 2015)

Mbit said:


> Dude I know I thought we were meshing then he threw that out, hmmmmmm.


See that now that's smart, in the interview process, you're evalutating them too. 


Mbit said:


> I shut the laptop and he says "Those were some nice pictures but they could have been your friend's work and you just stood there for the photo!" 🤣🤣🤣


The thing that bothers me here is not that he had that thought, people can wonder. However if he knows the work at all, he'd have been able to ask some questions and very easily see whether you did the work or you copied a photo. Instead he chose to just question your honesty and leave it hanging out there. 

He might be the chronically suspicious type, also possible he was just trying to take you down a peg or two so he can make a lower offer. Either way, nobody's perfect but I think you're definitely right to subtract points here.


----------



## backstay (Feb 3, 2011)

splatz said:


> See that now that's smart, in the interview process, you're evalutating them too.
> 
> The thing that bothers me here is not that he had that thought, people can wonder. However if he knows the work at all, he'd have been able to ask some questions and very easily see whether you did the work or you copied a photo. Instead he chose to just question your honesty and leave it hanging out there.
> 
> He might be the chronically suspicious type, also possible he was just trying to take you down a peg or two so he can make a lower offer. Either way, nobody's perfect but I think you're definitely right to subtract points here.


You assume the interviewer know electrical. I remember my mill interview. There were four other people in the room. One HR, one management, two electrical.


----------



## Almost Retired (Sep 14, 2021)

of the four i had only 1 electrical, he was a salaried supervisor


----------



## Mbit (Feb 28, 2020)

splatz said:


> The thing that bothers me here is not that he had that thought, people can wonder. However if he knows the work at all, he'd have been able to ask some questions and very easily see whether you did the work or you copied a photo. Instead he chose to just question your honesty and leave it hanging out there.


Yeah man, I couldn't tell if he was joking or serious. Sometimes I feel like I was raised on a different planet and I'm not that old.


----------



## mburtis (Sep 1, 2018)

You can't let poeple who know how to do the job be involved in the interview process, that just wouldn't make any sense.. You have to find poeple who's only knowledge of the job is what they read in the job description, those are obviously the poeple that get paid more and are qualified to pick new employees.


----------



## Mbit (Feb 28, 2020)

backstay said:


> You assume the interviewer know electrical. I remember my mill interview. There were four other people in the room. One HR, one management, two electrical.


I should have said that he is the office manager I guess and also an electrician.


----------



## splatz (May 23, 2015)

Mbit said:


> I should have said that he is the office manager I guess and also an electrician.


I guess I assumed that because why would you show the pictures to an HR-only person, for all they know you could be showing them the inside of a piano


----------



## backstay (Feb 3, 2011)

splatz said:


> I guess I assumed that because why would you show the pictures to an HR-only person, for all they know you could be showing them the inside of a piano


Half the people on here don’t know what his pictures are!


----------

