Changing breaker live

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rookie4now

Senior Member
I consider myself to be pretty safe, but maybe I'm wrong about this. We have to change a breaker (HKD65K 400A 3-Pole). I was going to shut down the breaker we are changing, and change it. My boss says I'm crazy to change that breaker with the panel live and that we shoud shut down the main feeing the bldg to kill our panel, then change the breaker.

I agree it would be better to kill the power, but it would kill power to 20 tenants in a mall. I figure that's why the management calls a trained professional who isn't going to kill themselves in a panel.

Is it common practice to kill the main first? I don't want to be unsafe, but I don't know why he feels this is risky. Obviously I'll do it however he want is done, I'm just curious what others do.

Thanks.
 

daleuger

Senior Member
Location
earth
That's not the BEST option. Like you said you should kill the main if possible but it's not always feasible. It can be done if you do it very carefully.

Quick question though. Is it a snap in or bolt in breaker?
 

zog

Senior Member
Location
Charlotte, NC
Your boss is correct. Changing that breaker live is a violation of the NFPA 70E and OSHA (See FAQ #3 here http://forums.mikeholt.com/showthread.php?t=99114 )

Change it when the mall is closed, simple as that. A "trained professional" should know the dangers of changing that live, have you calulated the Ei for that panel? I dont think you understand what the dangers really are. You need some 70E training my friend, and quick.
 

iwire

Moderator
Staff member
Location
Massachusetts
1910.333(a)(1)

"Deenergized parts." Live parts to which an employee may be exposed shall be deenergized before the employee works on or near them, unless the employer can demonstrate that deenergizing introduces additional or increased hazards or is infeasible due to equipment design or operational limitations. Live parts that operate at less than 50 volts to ground need not be deenergized if there will be no increased exposure to electrical burns or to explosion due to electric arcs.


Note 1: Examples of increased or additional hazards include interruption of life support equipment, deactivation of emergency alarm systems, shutdown of hazardous location ventilation equipment, or removal of illumination for an area.


Note 2: Examples of work that may be performed on or near energized circuit parts because of infeasibility due to equipment design or operational limitations include testing of electric circuits that can only be performed with the circuit energized and work on circuits that form an integral part of a continuous industrial process in a chemical plant that would otherwise need to be completely shut down in order to permit work on one circuit or piece of equipment.


Note 3: Work on or near deenergized parts is covered by paragraph (b) of this section.



I agree it would be better to kill the power, but it would kill power to 20 tenants in a mall.

My safety is not worth less then the tenants power, do it off hours.

I figure that's why the management calls a trained professional who isn't going to kill themselves in a panel.

I see, so all the electricians that have been killed doing hot work where simply not professionals and you are.

Yeah you should go for it and be man.

http://www.youtube.com/watch?v=PHs14ZTo96M
 

daleuger

Senior Member
Location
earth
Look up what "feasable" means. This situation is feasable.


You're going to butcher me over a spelling error? Seriously?
The part that is not "feasable" is shutting off 20 stores in the middle of the day. Sure he could go in at night but he never said if that was an option or not. It may not be.
 

iwire

Moderator
Staff member
Location
Massachusetts
That's not the BEST option. Like you said you should kill the main if possible but it's not always feasible. It can be done if you do it very carefully.

Anything supplied by the utility can be shut down, it happens when cars hit poles and during storms. Generally it is better to be planned then unplanned.

If you do just 'go for it' and an accident happens and does not happen to hurt anyone the damaged equipment will likely keep the power off much longer then a planned outage.
 

iwire

Moderator
Staff member
Location
Massachusetts
You're going to butcher me over a spelling error? Seriously?
The part that is not "feasable" is shutting off 20 stores in the middle of the day. Sure he could go in at night but he never said if that was an option or not. It may not be.

No not your spelling, your understanding of the definition of infeasible.
 

daleuger

Senior Member
Location
earth
Anything supplied by the utility can be shut down, it happens when cars hit poles and during storms. Generally it is better to be planned then unplanned.

If you do just 'go for it' and an accident happens and does not happen to hurt anyone the damaged equipment will likely keep the power off much longer then a planned outage.


Ok, Bob.....I'm getting tag teamed now.
Is "practical" a slightly better term?
 

zog

Senior Member
Location
Charlotte, NC
You're going to butcher me over a spelling error? Seriously?
The part that is not "feasable" is shutting off 20 stores in the middle of the day. Sure he could go in at night but he never said if that was an option or not. It may not be.
I did not even notice a spelling error, spelling is not my forte' and I hate grammer cops. No matter how you spell it shutting down power to 20 stores in a mall is very feasable when it comes to OSHA's ruling in electrical accidents. IMO your advice to the rookie4now is dangerous and a violation of OSHA laws.
 

iwire

Moderator
Staff member
Location
Massachusetts
Ok, Bob.....I'm getting tag teamed now.
Is "practical" a slightly better term?

Driving up to the mall at noon time and thinking you can dump 20 stores is infeasible.

Planing in advance with mall management to come in after hours while only the cleaning staff is in the mall is entirely feasible and the type of thing I do all the time.
 

daleuger

Senior Member
Location
earth
I did not even notice a spelling error, spelling is not my forte' and I hate grammer cops. No matter how you spell it shutting down power to 20 stores in a mall is very feasable when it comes to OSHA's ruling in electrical accidents. IMO your advice to the rookie4now is dangerous and a violation of OSHA laws.

Haha well we did spell feasible two different ways and you had it in quotes. I thought it was a double entendre with the spelling and definition. It's not a regular thing obviously but I challenge anyone on this forum with more than 5 years in the trade to be able to HONESTLY say that they have NEVER changed out ANYTHING live.
 

iwire

Moderator
Staff member
Location
Massachusetts
I challenge anyone on this forum with more than 5 years in the trade to be able to HONESTLY say that they have NEVER changed out ANYTHING live.

And that means what exactly? :smile:

I am sure many of us have done a lot of things over the course of our own lives that where stupid and dangerous, that does not mean we should recommend others to follow our stupid decisions.

In this case the OP is talking about installing a 400 amp breaker, it is a safe bet the panel it is going in has a very large avaible fault current.

So lets say he makes a mistake and shorts a phase...

http://www.youtube.com/watch?v=-iClXrd50Z8


and if it goes badly this can happen
 

daleuger

Senior Member
Location
earth
And that means what exactly? :smile:

I am sure many of us have done a lot of things over the course of our own lives that where stupid and dangerous, that does not mean we should recommend others to follow our stupid decisions.

In this case the OP is talking about installing a 400 amp breaker, it is a safe bet the panel it is going in has a very large avaible fault current.

So lets say he makes a mistake and shorts a phase...

http://www.youtube.com/watch?v=-iClXrd50Z8


and if it goes badly this can happen

Ok....COMPLETELY my bad!!! I don't know how I skimmed over the part about it being 400A. Holy foot in my mouth now :rolleyes:

That's a different animal all together. That's just ludicrous. I'll jump on the band wagon and say whoever said do that needs to be shot if it's 400A.
 

Twoskinsoneman

Senior Member
Location
West Virginia, USA NEC: 2020
Occupation
Facility Senior Electrician
How about praticable? That is a uncommon word the code likes to throw around..

Just want to throw my opinion out there. Absolutely shut off the power. As a professional I would certainly offer to come in after hours but even if it is not an option I would shut off power. A half hour of inconvience will be forgotten instantly. A life time of suffering of a family without there loved one....not so.
 

iwire

Moderator
Staff member
Location
Massachusetts
How about praticable? That is a uncommon word the code likes to throw around..

I think so too and I think it is worth noting that the code uses the term Impracticable which IMO is much different then Impractical.

Some here do not agree with me but it is my opinion that

Impracticable = Imposable

Impractical = Difficult
 

Twoskinsoneman

Senior Member
Location
West Virginia, USA NEC: 2020
Occupation
Facility Senior Electrician
I think so too and I think it is worth noting that the code uses the term Impracticable which IMO is much different then Impractical.

Some here do not agree with me but it is my opinion that

Impracticable = Imposable

Impractical = Difficult

Seems like it would be hard argue a definition.

Impracticable meens impossible I agree with you 100%.
 
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