Add a lug - live or dead...

[e57]

Situation - need an additional lug on each of the tabs of this 4000A vertical bus on this feeder. Roughly 18 floors from the service, 19 from the transformer - Engineer currently calc'ing the AIC...

Shutting down includes 18 floors of high rise resi, which I am more than happy to do - but will take some doing and coordination... My concern is that the fused switch for it has not opened since 1963 - nor have many of those attached to it down stream. I figure on taking most of the units off individually, knocking down the main - DOING IT - then main back on, then all the units that get taken out first.

Or - suit up and go live - pull one bolt and add one to the back side with just the units on this floor off...

I have no way of assessing the 4000A switch condition without shutting it off....

 

[M4gery]

I'd do it hot, but that's just cause I'm silly like that. New tricks, old dog, you know how it goes...

 

[hillbilly1]

Since they obviously have not done any preventive maintaince, it would be better to have a scheduled shut down, and find out if there any problems now, instead of the problem surfacing down the road at the wrong time with the building full of people.

 

[cadpoint]

Since they obviously have not done any preventive maintaince, it would be better to have a scheduled shut down, and find out if there any problems now, instead of the problem surfacing down the road at the wrong time with the building full of people.

Let the POCO do it on the street! Do all the other turn off as you said.

Or bring in one of those generators on a flat bed, I've sure they love the thought of that!

Call ahead for the Fuses... you are going to replace them aren't you?

Good Luck!!! :thumbsup:

 

[e57]

Let the POCO do it on the street! Do all the other turn off as you said.

Or bring in one of those generators on a flat bed, I've sure they love the thought of that!

Call ahead for the Fuses... you are going to replace them aren't you?

Good Luck!!! :thumbsup:

POCO transformer is in the 4th sub-basement of a 20 story building - and POCO does not own the 4000A riser buss from the 8000A service - they just have 3 meters per floor on the feeders to each unit. The building service will still be up, as will the house panels so I wont have to do it in the dark.

I have no way of knowing what the fuses are until I open the 4000A switch that would allow me to open the hatch to see them.

Generator - now thats funny???

 

[hurk27]

Or - suit up and go live - pull one bolt and add one to the back side with just the units on this floor off...

View attachment 5958

Ok now I have done a few "add a lug" installations before, but not sure what you mean about pulling a bolt?

If it means removing the bolts holding the existing lugs then I got to say that is crazy, to loosen up a lug under load would be suicidal, and even if you could floating the neutral would not be a good idea?

I'm I missing something?

 

[jumper]

I just do not know what to say.......:happysad:

 

[M4gery]

Ok now I have done a few "add a lug" installations before, but not sure what you mean about pulling a bolt?

If it means removing the bolts holding the existing lugs then I got to say that is crazy, to loosen up a lug under load would be suicidal, and even if you could floating the neutral would not be a good idea?

I'm I missing something?

After the part of his quote that you highlighted in red he said "with just the units on this floor off...". Because of that, the lugs that he would be loosening would not have any load on them.

 

[iwire]

Situation - need an additional lug on each of the tabs of this 4000A vertical bus on this feeder. Roughly 18 floors from the service, 19 from the transformer - Engineer currently calc'ing the AIC...

Shutting down includes 18 floors of high rise resi, which I am more than happy to do - but will take some doing and coordination... My concern is that the fused switch for it has not opened since 1963 - nor have many of those attached to it down stream. I figure on taking most of the units off individually, knocking down the main - DOING IT - then main back on, then all the units that get taken out first.

Or - suit up and go live - pull one bolt and add one to the back side with just the units on this floor off...

e57 that was a stupid question.

You shut it off, period.

OSHA requires you to shut it off and you would be an idiot not to shut it off.

You are no longer in the military, you are not expected to risk your life or comfort so that people don't miss Judge Judy.

 

[M4gery]

OSHA requires you to shut it off

How does OSHA require e57 to shut it off?

 

[iwire]

How does OSHA require e57 to shut it off?

You really want to split hairs on this?

Even if OSHA and 70E did not exist it would be a stupid move to do this work hot. I have done similar in the past when I still young enough to be stupid.

But I assume e57 is an employee.

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.

None of the above allows installing new equipment to live gear in this building.

 

[M4gery]

You really want to split hairs on this?

No, not at all.

But I assume e57 is an employee.

His profile says that he is a "Contractor" which means that OSHA does not require him to shut it off.

I am not splitting hairs, just discussing facts.

 

[Hv&Lv]

No, not at all.
His profile says that he is a "Contractor" which means that OSHA does not require him to shut it off.

I am not splitting hairs, just discussing facts.

I wonder if he will be attempting this all alone without any help...

 

[M4gery]

I wonder if he will be attempting this all alone without any help...

In my experience, working in tight gear like this, it is easier and safer to work by yourself. It's much easier to coordinate your own two arms without someone else's in there too.

 

[iwire]

No, not at all.
His profile says that he is a "Contractor" which means that OSHA does not require him to shut it off.

I agree OSHA does not apply to an employer and yes I agree that is a fact.

Now, what do many contracts require?

Full compliance with 70E.

 

[M4gery]

I agree OSHA does not apply to an employer and yes I agree that is a fact.

Now, what do many contracts require?

Full compliance with 70E.

If that were the case, then the answer to his question is very clear.

 

[jeremysterling]

My concern is that the fused switch for it has not opened since 1963


I had the same concern about some "older" gear (not 50 years old, though!). I was like cadpoint wanting the POCO to put the switching on their gear. My boss heard my concern but the the job went forward with sequential load shedding, operating the "older" gear and the scheduled outage went fine. Some broken partition brackets were replaced in addition to the original scope of work and everything sequentially reenergized.

Schedule an outage to add the lugs.

 

[Volta]

No, not at all.
His profile says that he is a "Contractor" which means that OSHA does not require him to shut it off.

I am not splitting hairs, just discussing facts.

I agree OSHA does not apply to an employer and yes I agree that is a fact.

Now, what do many contracts require?

Full compliance with 70E.

He would pretty much need to be a sole-proprietor or a partner, if he has organized a corporation then he would still be an employee.

But physics don't care.

I am gonna guess that this incident energy could be over 40 cal. And you can certainly get a suit that is rated to protect from heat higher than that. But the reason that 40 is used as the top-end limit is not the heat.

Remember that an arc flash has more than the incredible heat, but the explosive force too. The best reason for a 100 cal suit is to contain the mushy jelly one is expected to be turned into when slammed into the opposite wall. Holds the juices in.

But if you did do this energized, you probably have a good chance of being ok. I mean, you are pretty darn likely to live . . . over 90%, I bet. :roll:

 

[Cow]

I'd schedule an outage too. Sounds like a good time to excersise some switches, if you're really worried they haven't been opened or maintained since '63. Maybe you could use that as an excuse to have someone go through and do some preventative maintenance on the switches at the same time you work on the lugs.

 

[M4gery]

But if you did do this energized, you probably have a good chance of being ok. I mean, you are pretty darn likely to live . . . over 90%, I bet. :roll:

If you want to partake in throwing out baseless odds, I'll join in too. I'll bet that an experienced, skilled electrician has a better chance of getting hurt in a car accident while driving to work one day than adding the lugs as the OP described.