OT- Wiring of mcb in a panel

[TurpoUrpo]

Winklehoffen, you are one super human. I wish I was that capable.

I agree with Winklehoffen and Geospark.

I'm very much taken a back by this "its this dangerous wiring practices fault, NOT OURS!".. Try to find the fault where it is, not blame it on something else.

 

[Lancie1]

TurpoUrpo, It seems that you think safey codes and standards should be based on what humans should be and hope to be, not what they really are?

 

[Calistodwt]

The mcb's all have the supply in the bottom and load out the top. The drawings show power in the top and load out the bottom which is what i would expect.

Firstly you need to if the drawings are right or wrong? If the drawings are wrong then they should be marked up to show the reality. It will probably be more expensive to change the panel wiring. I would actually verify which way the customer would like to have the panel. However your company would probably not be happy having to correct the problem at their expense.

 

[TurpoUrpo]

TurpoUrpo, It seems that you think safey codes and standards should be based on what humans should be and hope to be, not what they really are?

No one has yet to show any safety code prohibiting wiring reversed.

Also i dont see how overdoing safety codes would result in better safety, its false safety, think about all those old installations that can be anything.. I think emphasis should and must be on responsibility of one doing the job, "always check, and check again" for everyone. Hiding behind code or what ever is just accident waiting to happen.

If code would change to say reverse wiring is not allowed. Period. That does not suddenly make every old installation follow the code. Teaching focus on "code says this and that" instead of "check, and check again". Would result in lots of accidents. I say again, emphasis must be on everyones own responsibility to do his job safely.


Edit. Let me just add, that being wrong or no, i would not design system like it, or like systems designed like it. But op wanted something hard to get the design changed. There is none it seems. So only thing there is to it, is to use these "soft" values to try to get it redone.

 

[katratzi]

then why "Line" and "Load" markings if there is NO difference.

 

[katratzi]

and Lancie, you're better than I am for not calling BS on these capable people. There is no way anyone checks all aspects of every situation before they make a physical movement. Do you test load each step before you go down a set of stairs?

 

[TurpoUrpo]

then why "Line" and "Load" markings if there is NO difference.

Who said there is NO difference? No one has been saying that. Please read the whole thread.

 

[Winklehoffen]

and Lancie, you're better than I am for not calling BS on these capable people. There is no way anyone checks all aspects of every situation before they make a physical movement. Do you test load each step before you go down a set of stairs?

Of course nobody tests every aspect of every situation but there are many things we do without thinking as we go about our daily lives. I always look where I'm sitting before I sit down - it prevents me from hitting the floor or falling down the long drop. I always check the car is in neutral before I turn on the ignition. I always look left and right when I cross the road. Pertinently to this particular discussion, I always check a panel is properly isolated before poking my fingers around in it. Many of these actions are subconcious and have become second nature to me after years of experience and instruction and are the reasons why my son still has his father around to play Lego with him.

 

[Lancie1]

Of course nobody tests every aspect of every situation but there are many things we do without thinking as we go about our daily lives.

I agree with that completely. That was my point. Some of those things we do without thinking eventually do get us in trouble. We get in a repetitive rut, thinking our actions have been safe in the past and will continue to be safe. Follow the rules, do it the same way, and our sons will have their fathers home at night.

Then we find out that Someone Else has done something that if we follow our usual old safe methods (checking a breaker on the Load Terminals), makes our normal safe repetitive daily actions dangerous to our lives.

I think most accidents are usually the result of more than one failure. For example if the HV probe had not failed, the electrician probably would not have died. That was the official OSHA accident report conclusion. But it is also true that if that breaker had not been wired in reverse, he also would not have died - would not have put the faulty probe across hot wires. If he had been wearing a face shield and a rubber suit, he might not have died. Two or more abnormal events can lead to an accident, even where one single event may not have.

 

[cjd1965]

Hi
Nice to see the interest in the topic

I am going to the site where this is located tomorrow. Due to not having anything to 'hang my hat on' I am going to redline the drawings for markup and leave the panel as it is. Our customer does not have an electrical resource so they don't have an opinion. The top-to bottom /left-to right school of thought that was mentioned earlier in the thread.

Interesting points expressed... and I would ask why a contactor/overload arrangement has the overload clipped to the bottom if their is no "normal" way of feeding equipment but of course that would be another can of worms.

Of course I have seen panels mounted upside down or on their side due to space issues or cable entry issues but by design I still don't agree with the practice, but I was trained to top feed fuses and from back in the days when I was apprenticed but as many have said their is no CE/EN regulation so I have to accept it



Cheers

 

[DwSoFt]

The Plc Kid, I know it was a rant, but in post #6, your first and last paragraphs are highly contradictory? It cannot be both a legal method of wiring and also a life safety issue? The latter would not allow the former. What is normal practice one side of the globe may be outlawed on the other. But your mis-understanding the real and common danger here.

But, no matter how many people tell you what is considered right or wrong, normal or abnormal, you should decide for yourself.

Remember, I have never said that you should or should not accept this panel. I have only outlined where you should stand, and that you cannot argue the case, to have it changed, based on it being dangerous, it is not. It's whether or not your company allows it. That decision still has to be made. Or perhaps its already been made, you just don't know it yet?

i find this funny, as you accuse PLC kid as contradicting himself, but then you contradict yourself as well. U say not to let anyone but each person decide for themself but then tell someone how they should be thinking, and that isnt right either.

i agree that you should also always check EXISTING installations. However if i was installing it i WOULD NOT bottom feed it, because i am the one installing it. because it is best practice IMHO. not against codes or nothing. but as Lancie 1 said

That is one thing to ask when you see a stupid situation like this: who benefits from allowing it to continue?

it is possible that the reason its not illegal is due to corporations. we dont have all the power. money talks... but that is a different conversation altogether


back to the point i agree with some of your points GEOSPARK, but i have seen numerous threads where you demand people thing exactly like you. no, we should all decide for ourselves. he asked for advice on his beliefs, and the posts before yours helped him with that. Lancie1 and PLC kid, both have alot to share with the community here. i know i have learned a bunch from them.

 

[Geospark]

It appears I have some catching up to do? I have been traveling for work and also had a short family holiday. So now I'm back and ready to continue. I'm glad to see a debate opening up on this matter, but let's try keep it civil.

Dan, both these fine gentlemen have a lot of experience and knowledge to dispense on these forums, but the right to do so is not exclusive to them. I have also learned a lot from them over the years reading here. I have the highest respect for both of them. But the relevance and weight of posts here should not be determined, alone, by the number of posts one has on this forum. As great as this forum is, my experience did not start at post one, it started many years ago on the job. The fact I have only recently become active on these forums is because I feel I now have some knowledge of my own to dispense, which, like others, I also freely do. What I do here, I feel, is for the good of others, not for the sake of argument. I am not here to start a fight with, or discredit anyone.

You recently defended Lancie1's honour on his admission of being incorrect in another matter. Now you are here to defend him again. I understand that and share your final sentiments in that other thread.

Lancie1, regarding that other topic, I think more of you for admitting when your were incorrect, not less. I was sad to read you are considering posting less on these forums. Don't let it stop what you obviously love doing, helping people.

Having said all that. It shows how any of us, no matter how experienced we think we are, are not always correct and should be open to criticism and correction where it needs be, including me.

You are correct, Dan, to point out my hypocrisy in that case. I am clearly biased in this matter, for good reasons I feel. But I have not, or am not, intentionally trying to make anyone's mind up for them. I do want people to decide for themselves. I apologize to anyone who may feel otherwise. However, I don't apologize for my passion for safety. I am merely putting a strong case across as I am trying my best to promote the safe practices that should be default in all of us exposed to this risk, electricity. I did not invent these safe practices, they have been around for a very long time.

It appears to me that some think these safe practices are optional in our duties, and want to rely on other methods to safe guard them, when a safe and proved method of test and verification exists. One which will not only safe guard them from this assumed greater risk, but the many variations we are likely to come across during the course of our duties.

Winklehoffen, I appreciate you replying in my absence. You may have felt I had given up? Not so, I was just busy.
I'll now reply to Lancie1's post #26, and others.

...if the dead man knew that the bottom of the breaker was hot...

He could never know, for certain, if the top or bottom was hot, until he tested. Anything else is an assumption.

...he might not have stuck his probe on the bottom terminals without checking it first...

He should not have stuck his probe on the bottom terminals without checking it first.

...He might have been more careful, but he assumed it was dead and safe...

He should have been more careful, he should not have assumed it was dead and safe.

...willing to risk his life based on a false assumption.

If he was "willing to risk his life based on a false assumption", he was negligent with his own life. It was his own fault, not the fact the supply was on the bottom.

The bottom line I stated was if the breaker had been wired in the standard way, probably this guy would still be alive

I fully agree, but the assumption should never have been there. He did not fully respect the potential danger before him.

If he placed his probe on or near the bottom of the breaker on the assumption that it should be dead, without testing his probe first, he was complacent. It is highly probable that this is what happened, but we may never know.

You are picking at straws, old buddy. Just because you can't understand why it is dangerous doesn't make the practice safe either.

I don't pick at straws, Lancie1. I explain my position in detail. Picking at straws is when someone has no real argument to make and so picks anything and everything to try make a case. I wrote a lot, including that statement, but that was all you chose to pull me up on? Who is really straw picking?

However, I agree with your statement. I was indicating the reverse of what they think in this case. From a neutral point of view, it should not be considered to be either, until you weight it up and decide for yourself. That's the message I was trying to convey to cjd1965, albeit hypocritical in the end, thank you Dan.

We all make assumptions every day where we will be killed if our assumption is wrong. For example, did you drive through a green traffic light today? You assumed that the probability was high that you would be safe, but that was only an assumption. Why did you think it was safe though? Was it because you had done it thousands of times before and got away with it? The only automobile accident I have ever been in was while going through a green light. My assumption was wrong, and I could have been killed.

Now you are assuming that I assume? These damned assumptions!
I'm trying to point out how too many people make assumptions for themselves, but now your making assumptions for others, namely me.

But your quite right, we all make assumptions every day of our lives. We become conditioned to the environments around us. We probably assume way too much, but, we need to live as well.

So how do we strike a balance?

The assumptions we make should only be in situations where there is little to no risk. Decisions with higher risk, particularly with regard to safety of life, should be treated differently. So what do we do instead of assuming?

We take calculated risks.

A calculated risk is where we decide whether or not something is worth the risk for the reward.

Driving is highly useful in todays world, essential we might say. So we decide it is worth the risk for the reward.
So, as part of this calculated risk, we set safety standards for the automotive industry, introduce laws to deter bad drivers, we set speed limits, limit or prohibit drink driving, we use traffic lights to control movements, we use signage, we mark roads and junctions clearly, we use seat belts to help protect us and we train drivers to be competent and safe on the roads. All this helps reduce the risks involved, but not remove them. But even with all these measures, you still need to have a healthy respect for the inherent dangers of driving.

When I go through that green light, the only thing I'm assuming is that anything could happen. I try to use my training. I make sure I'm concentrating to the best of my ability. I cannot control what others may do, but I can try to control how and when I react. The measures in place will hopefully help to reduce any possible accidents I may have. I'm taking a calculated risk each time I drive.

"My assumption was wrong, and I could have been killed"

There are many factors involved in driving that are outside of our control. So we need to be alert to their possibilities at all times.
If you are driving around assuming you will be safe all the time, you are not using safe practices in driving. You are being complacent. I'm trying to convince you to think the opposite way my friend. Try assuming you will be killed every time you go through those green lights and see what difference it might make?

Likewise with electricity. You do not assume anything as you carry out your work, other than everything is live until you verify it is off. We are skilled labourers, highly trained at what we do. We should be competent and authorized persons. This is what sets us apart from everyone else prohibited access to this risk. If we do not posses this competency, we should not be anywhere near electricity.

More to come...

 

[Geospark]

UL Reverse Feed Standards Requirements

UL 489—Molded case circuit breakers, molded case switches, and circuit breaker enclosures
Per UL 489, there are clear test performance and marking requirements for circuit breakers and molded case switches that are UL Listed as being suitable for reverse-feed applications. UL 489 requires reverse-feed circuit breakers to meet certain construction requirements, and to be tested and marked accordingly, as follows:
1 Tested per UL 489, Paragraph 7.1.1.18
2 Markings per UL 489, Paragraph 9.1.1.13

Testing Requirements
Per UL 489, Paragraph 7.1.1.18: Except for single-pole circuit breakers tested singly, if a circuit breaker is not marked “Line” and “Load,” one sample of each set tested, or one additional sample, shall be connected with the line and load connections reversed during the overload, endurance and interrupting tests.

This UL test requirement specifies that for circuit breakers and molded case switches to be UL Listed for reverse-feed applications, samples shall be tested with the line and load terminals reverse-fed, as shown in Figure 2, and that the test results shall be the same as those of “normally” fed circuit breakers. Depending on the design configuration and construction, the circuit breaker may or may not be affected by the application of power in a reverse-feed connection during these tests.

Marking Requirements
Per.UL.489.Paragraph 9.1.1.13: Circuit breakers shall be marked “Line” and “Load” unless the construction and test results are acceptable with the line and load connections reversed. This marking requirement specifies that UL Listed circuit breakers and molded case switches shall be marked with the word “Line” on one end of the circuit breaker and the word “Load” on the other end, as shown in Figure 3, if they are unable to successfully meet the reverse-feed test requirements per Paragraph 7.1.1.18 of UL 489. Conversely, a UL Listed circuit breaker does not have to be marked with “Line” and “Load” if it successfully meets the reverse feed test requirements.

I don't see how citing UL 489 is relevant here? No one is disputing what anyone calls either method of wiring a circuit breaker. The argument you are making is why it is more dangerous. They call it normal and reverse, not normal and abnormal, or dangerous? This is just terminology.

UL 489 is the reverse feed test procedures that must be carried out on a circuit breaker, that does not carry the markings "line" and "load", before it can be UL listed.

"...a UL Listed circuit breaker does not have to be marked with “Line” and “Load” if it successfully meets the reverse feed test requirements."

They are outlining what must be done to prove reverse feed meets the same requirements as normal feed. Unless they changed the description at some stage, it does not indicate that Underwriters Laboratories are moving in the direction towards banning reverse feed circuit breakers. The wiring diagram clearly shows the direction of the conductors, in this case, to remove all ambiguity while carrying out the reverse test. It does not stipulate this is how it should be represented in wiring schematics.

then why "Line" and "Load" markings if there is NO difference.

Katratzi, I don't think you've read the above correctly? "line" and "load" should only be marked on circuit breakers that do not meet the requirements of UL 489 reverse feed tests. Any circuit breaker you see with these markings should not be reverse fed. No one here is saying they should be.

You can not understand why it is dangerous if you look only at the physics, the performance, and the electical characteristics of a circuit breaker. That will lead you to the conclusion that most circuit breakers are two-way streets, and that electric current can and will flow either direction. All true.

The danger comes when you bring in human characteristics. People get into modes of action-reaction without ever thinking about what they are doing? Do you flip on your turn signal when you turn your car steering wheel sharply, even if you are not making a turn? Do you sit down on the commode without checking the position of the lid? Do you flip a light switch down to turn it off, even if that turns it on because it is a 3-way switch?

If we were machines or computers we would do none of these things. Neithter would we assume that the dead wires on an OFF circuit breaker are on the bottom. But we are not machines and we do make those assumptions. The Human Factor is why certain practices can be dangerous. It is a real problem, and no amount of instructon or training can completely overcome the fact that we are failable, weak, soft, unstable Humans.

As you state...A "human" looks at the electrical characteristics of a circuit breaker. This is how they draw the conclusion that the electricity may potentially flow in both directions. This is the real danger I demonstrated in my very first post. How are "human characteristics" not involved in this process? Trained, competent people, do not "get into modes of action-reaction without ever thinking about what they are doing". It does not take us being machines to remember this simple rule.

Always verify the supply is off at the point of work.

"The human Factor is why certain practices can be dangerous."

Yes, the unsafe practice of not testing because you are assuming it should be dead.

Human characteristics is what my argument is all about. Helping people to keep themselves safe by training their characteristics to a much safer mentality. Using this method is what keeps me safe and gets me home each day, not how someone wires things. I choose to use the safer method of thinking that everything is dangerous, including top fed circuit breakers, but no less dangerous than bottom fed ones.

Winklehoffen, you are one super human. I wish I was that capable.

Is it too much to comprehend that someone may not be as forgetful as you are? Blindly sitting on toilets or chairs, which I'm also not in the habit of doing, only hurts your pride. It has nothing to do with what a trained professional does when dealing with life threatening tasks.

TurpoUrpo, It seems that you think safey codes and standards should be based on what humans should be and hope to be, not what they really are?

Safety codes and standards are based on having humans, working in dangerous environments, competently trained. Anyone else should not be there.

Then we find out that Someone Else has done something that if we follow our usual old safe methods (checking a breaker on the Load Terminals), makes our normal safe repetitive daily actions dangerous to our lives.

This is the whole point my friend. Our normal daily repetitive actions are not safe. They are dangerous to our lives, always.

Also, remember, all the codes and standards in the world will not stop an individual from intentionally, or inadvertently, wiring something incorrectly. Why assume when you need not?

To keep arguing that we do, and should continue to, go around assuming certain things are safe, while working on dangerous equipment, does not hold water, and again, is dangerous in itself.

G.

 

[The Plc Kid]

I will say this. GeoSpark has very valid points and one should always test and verify and never assume. In a perfect world that is how it would be but unfortunately we live in the real world.

The will always be someone who is poorly trianed,In a rush with a production god breathing down their neck,etc,etc that will make a assumption or not verify because it has always worked or every breaker he has encountered in his carreer has been top fed,etc.

These are by no means an excuse not to check and verify as GeoSpark said and I fully agree but the cold hard fact is people do assume even when they should not. People do turn the disconnect off and don't verify with a meter. It should not happen but in reality it does and that's all I am saying.

If you can avoid bottom feeding a breaker or disconnect and it saves the life of that one poorly trained or incompetent person who assumed when they should have check and verified In my opinion it's worth it. But to each his own.

I myself have bottom fed breakers before but their was a need to do so and it would have been difficult to avoid / change and I did document and and label it not for the seasoned sparkie but for the person who assumes when he should not.

Their is no harm in labeling it so why not do it? Just in case? Their is no harm in avoiding bottom feeding if you can so why not avoid it? Why take a risk where there is no gain?

The same argument could be held from wiring be fed from another panel. Code makes you color it Orange or Yellow but why? You should always check and verify right? But sometimes people don't even when they should and thats why you use orange or yellow to designate that.

I will continue to avoid bottom feeding when at all possible and when I have to I will mark and document it to the best of my ability and I will sleep well at night knowing that I did all that I could. If someone gets killed working in a panel I built my conscience will be clear knowing that I did all that I could to avoid a accident or death of someone.

Anyone else can do as they wish because we all have to answer for our own actions.

Party on

 

[Geospark]

The Plc Kid, you are dead right, pardon the pun.
If incompetent people, within our trade, did not exist, we would not be discussing this at all. It is these very people you are in fear for that I am trying to reach with my message.

If only some might read this thread and think a little bit more the next time they are carry out their work, I will sleep a little more soundly too.

G.