480V Electrical Cabinets

[hillbilly1]

Risk to human life under greater hazard test
The other exception the task infeasible in deenergized state and third testing and troubleshooting.
These three exceptions for live work with documentation allowed in court

The second exception is where they can get you (lawyers) you better have all of the PPE up to date and worn, all the precautions taken if there is an incident. Of course the could get you on the other too also, if an incident happened and any safety rules were violated.

 

[don_resqcapt19]

Risk to human life under greater hazard test
The other exception the task infeasible in deenergized state and third testing and troubleshooting.
These three exceptions for live work with documentation allowed in court

Those, other than troubleshooting are very difficult to document in the real world, and in the first case is not something I would ever do, energized work permit or not. The risk of energized work causing a shut down is just too big of a risk where the power must remain on to protect human life.

 

[jim dungar]

The risk of energized work causing a shut down is just too big of a risk where the power must remain on to protect human life.

Amen.

When I taught NFPA70E, I always asked why people were willing to accept an unplanned outage rather than a planned one.

 

[Deltaforce]

the first case is not something I would ever do, energized work permit or not. The risk of energized work causing a shut down is just too big of a risk where the power must remain on to protect human life.

Scenario the risk of a work-induced shutdown more the risk of the work live—is the primary justification the entire regulatory framework governing energized work (like NFPA 70E, Section 130.2(A)(1)).

 

[Deltaforce]

I always asked why people were willing to accept an unplanned outage rather than a planned one.

Because unplanned outage Hobson's choice

 

[Jraef]

In a nutshell, if you consider 480V to be “high voltage”, you are not qualified to open the door of that cabinet…

 

[tom baker]

Federally and most states employer domentation of knowledge, skills and training make a qualified person not just a Certified Electrician for live work
But in other states like California license may also required
OSHA rules on live work nfpa 70e followed in all states

Washington has not adopted 70E, but our rules are similar.

 

[ron]

That is not always the case.
In most cases, especially NFPA70E, it the employer that gets to decided which person(s) are qualified to perform specific tasks.

Even as a consulting engineer many companies considered me as a qualified person for performing some tasks associated with exposed energized equipment/conductors.

Agreed. Before I had my PE, my employer considered me to be a Qualified Person (although not an Electrician), and since my PE, they still do.

 

[don_resqcapt19]

Scenario the risk of a work-induced shutdown more the risk of the work live—is the primary justification the entire regulatory framework governing energized work (like NFPA 70E, Section 130.2(A)(1)).

Will never agree that live work can be justified in any case where a failure while doing the live work would result in loss of power to any equipment required to maintain life.

 

[Strathead]

In a nutshell, if you consider 480V to be “high voltage”, you are not qualified to open the door of that cabinet…

Let alone 220V.

 

[Strathead]

Stated simply as others have implied. When you work it hot, there is always the possibility that any "accident" will cause the power to shut off anyway. What if that happens? Is the owner actually saying they can't turn it off on purpose, but they have plans in place that can cover an accidental shutdown?

 

[pipe_bender]

Often times the electrical hazards associated with live maintenance in plants are just outdated designs, where something that has to be routinely done involves opening a 480V cabinet but nothing to do with touching 480V.
I occasionally get to pulled in to help out a plant-shutdown when they upgrade as they want to be up and running as fast as possible. After the last process line upgrade I noticed a pattern they designed it with lower voltage components in a few spots.

About 8 or 9 480V motors were replaced with VFD driven 240V,
120VAC PLC control panels and control circuits were replaced with 24V,
more separation and barriers between 480V stuff in the layouts.
240V panels that are a category 1.
Also the new PLC cabinets have two doors, one for the 480V side and a smaller one that was just the PLC / 24V / digital IO side. A tech used to have to open one door exposing him to 480V to just plug in a USB cable and update a program.
The panel is totally custom I was thinking it must have been very expensive but its worth the cost to avoid a shutdown.

 

[ggunn]

But if there is an accident, they have to prove the risk was worth working energized. Thats where lawyers come in. Mainly if risk to human life due to shutdown, is the only reason you can really get away with it. Financial loss will be not be a good excuse in a court case.

Not to put too fine a point on it, but risk to human life is a risk of financial loss.

 

[pipe_bender]

Specifically, a Cabinet that is energized and cannot be de energized.

In your bio-med equipment is the technician actually working on the hi-voltage parts while energized? or is it just other equipment in the same enclosure.?
The problem with the plant here was the panel builder was stupid,
the techs had to open up a full 400A 480V panel the size of a refrigerator to plug in a USB cable and update a program, or check a 120V relay nothing to do with the 480V at all.
So the redesign (by a new panel builder) simply separated PLC from the 480V.
They also have these 480V indicators on all the panels now so you know if the panel is de-energized before opening, because thats a another OSHA gotcha, you need PPE to open a de-energized panel unless you have those.

 

[BiomedTech]

In addition to everything else it must be justified energized work. It is not common when you can meet the requirements to justify energized work. However, there are provisions to permit troubleshooting on energized equipment.

Exactly what cannot be shutdown?

In the plant I spent a lot of time at, there was NO energized work, other than troubleshooting. They did have an energized work permit, and it required the signature of the plant electrical engineer and plant manager, but it was never used because the word from corporate was that if they signed that permit and something went wrong both of those persons would be fired.

There were a lot of projects where we did the preliminary work, and then waited months for an outage to complete the work. Even landing conductors for 120 volt controls was not permitted if the panel was energized.

MRI Machine

 

[BiomedTech]

In addition to everything else it must be justified energized work. It is not common when you can meet the requirements to justify energized work. However, there are provisions to permit troubleshooting on energized equipment.

Exactly what cannot be shutdown?

In the plant I spent a lot of time at, there was NO energized work, other than troubleshooting. They did have an energized work permit, and it required the signature of the plant electrical engineer and plant manager, but it was never used because the word from corporate was that if they signed that permit and something went wrong both of those persons would be fired.

There were a lot of projects where we did the preliminary work, and then waited months for an outage to complete the work. Even landing conductors for 120 volt controls was not permitted if the panel was energized.

I don't think the company got permits to even do the work. I am trying to educate myself, because my husband lost his job, but I don't think he lost his job because of what they stated. I think he lost his job because he got shocked and he brought to his company the fact that he/they should be wearing the proper PPE for the job and he would not have gotten shocked. No, I am not using any of this info for a lawsuit. I just want to be able to contact OSHA and know what I am talking about, so they do not write me off. I would hate to find out someone died because this company is not working within proper guidelines.

 

[roger]

MRI Machine

They can be shut down and cooled by outside water supply. There is more to it as far as bringing the whole unit down but it can be done.

 

[BiomedTech]

In your bio-med equipment is the technician actually working on the hi-voltage parts while energized? or is it just other equipment in the same enclosure.?
The problem with the plant here was the panel builder was stupid,
the techs had to open up a full 400A 480V panel the size of a refrigerator to plug in a USB cable and update a program, or check a 120V relay nothing to do with the 480V at all.
So the redesign (by a new panel builder) simply separated PLC from the 480V.
They also have these 480V indicators on all the panels now so you know if the panel is de-energized before opening, because thats a another OSHA gotcha, you need PPE to open a de-energized panel unless you have those.

It goes to the MRI, which never gets de energized without the Manufacture getting involved. don't think the company got permits to even do the work. I am trying to educate myself, because my husband lost his job, but I don't think he lost his job because of what they stated. I think he lost his job because he got shocked and he brought to his company the fact that he/they should be wearing the proper PPE for the job and he would not have gotten shocked. No, I am not using any of this info for a lawsuit. I just want to be able to contact OSHA and know what I am talking about, so they do not write me off. I would hate to find out someone died because this company is not working within proper guidelines.

 

[roger]

I don't think the company got permits to even do the work. I am trying to educate myself, because my husband lost his job, but I don't think he lost his job because of what they stated. I think he lost his job because he got shocked and he brought to his company the fact that he/they should be wearing the proper PPE for the job and he would not have gotten shocked. No, I am not using any of this info for a lawsuit. I just want to be able to contact OSHA and know what I am talking about, so they do not write me off. I would hate to find out someone died because this company is not working within proper guidelines.

Look into OSHA 1926 sub part K. I may not be citing the correct part but the PPE is required.

 

[BiomedTech]

They can be shut down and cooled by outside water supply. There is more to it as far as bringing the whole unit down but it can be done.

I understand it can be done, but once a unit is brought up, it takes a major act and a lot of upset people to take it down. It does not happen, else a repair is needed or someone is stupid. I have only seen one get shut down in my 25 yrs and that was because a hospital was stupid and performed water repairs without telling the Biomed Dept. Any others were being removed from service.