Removing old equipment

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dema

Senior Member
Location
Indiana
I am an electrical engineer who does design documents for construction. There is a situation where there are 1600A MDP's containing 13.8KV to 208V transformers. Looking at current information, these transformers likely weigh 6500 lbs or so.

The electrical contractors who toured the facility didn't seem to think that the phases could be separated with a blow torch. Why would that be?

Would somebody please describe for me the general procedure - and the responsibility of each task - of getting equipment like this out of the building?

I have stated from the beginning that this is not part of my scope as an electrical designer. There is no issue of my liability at all. However, I don't feel like anybody is taking this issue particularly seriously except the electrical contractors who are looking to me to tell them something. Which I won't - I understand liability - but I want to be able to ask enough of the right kinds of questions and provide enough of the right type of information so that this issue is properly addressed.

Thank you.
 

JFletcher

Senior Member
Location
Williamsburg, VA
I am an electrical engineer who does design documents for construction. There is a situation where there are 1600A MDP's containing 13.8KV to 208V transformers. Looking at current information, these transformers likely weigh 6500 lbs or so.

The electrical contractors who toured the facility didn't seem to think that the phases could be separated with a blow torch. Why would that be?

Would somebody please describe for me the general procedure - and the responsibility of each task - of getting equipment like this out of the building?

I have stated from the beginning that this is not part of my scope as an electrical designer. There is no issue of my liability at all. However, I don't feel like anybody is taking this issue particularly seriously except the electrical contractors who are looking to me to tell them something. Which I won't - I understand liability - but I want to be able to ask enough of the right kinds of questions and provide enough of the right type of information so that this issue is properly addressed.

Thank you.

Aside from communication cables, there is no requirement in the NEC that requires old/abandoned equipment be removed.

Are you saying the equipment would have to be partially/completely disassembled to remove it from the building? If a new MDP of the same size were to be installed, how would you get it in the building?

You might contact someone who specializes in salvage/scrapping to get some different ideas.
 

dema

Senior Member
Location
Indiana
The old equipment has dry type transformers. The new equipment is going into another location. Part of the difficulty is that the new equipment is going in first in a more open location. The new transformers are 480V primaries. The old ones are 13.8KV primaries. The difference in weight for the same KVA is phenomenal. The high voltage according to modern tables are over 6000 pounds. The 480V are only 2000 pounds. (Only and 2000 shouldn't go in the same sentence. :) )

New ones are near window walls. Old ones are tucked under other floors behind staircases.

We have considered that they may end up abandoned in place - or at least the transformer section may.

I'm an engineer and not a contractor and I am constantly trying to learn new things about how to make a job easier, less frustrating, and therefore less expensive. For large gear the meter shouldn't be directly on the outside of the gear. Offsetting it makes the turns easier - that kind of thing. So anything that you can tell me that would help me to smooth out this process would be great.

(I think the contractors find me easy to work with. I do get comments and suggestions - and the bids on my jobs tend to come in very close to the same number. I think getting three bids within 1-4% of each other is one indication of comprehensive drawings. But I can always do better.)
 

Ingenieur

Senior Member
Location
Earth
Is this a pre-bid rfi?

I've never seen anything that could not be removed
they got it in, it can be gotten out lol
function of time and money
methods and means should be up to the contractor and he should price accordingly

without seeing the floor plan and equipment details hard to evaluate
may need to take a wall down etc
make sure the spec requires them to put it back to like they found it
 

growler

Senior Member
Location
Atlanta,GA
The electrical contractors who toured the facility didn't seem to think that the phases could be separated with a blow torch. Why would that be?


A "blow torch" is not used for cutting or welding but is use to supply heat over a large surface area.
 

growler

Senior Member
Location
Atlanta,GA
Would somebody please describe for me the general procedure - and the responsibility of each task - of getting equipment like this out of the building?


Once the equipment is disconnected and safe it doesn't really matter who moves it out of the building. It becomes the responsibility of the company that contracts to do the work. Moveing an old peice of equipment would be a job for millwrights ( that's the type of work they normally do and they probably have the equipment to do it). 6500 LBS isn't that heavy if there is room to get the equipment out.
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
So much of this seems odd to me, coming from an electrical engineer...

I am an electrical engineer who does design documents for construction. There is a situation where there are 1600A MDP's containing 13.8KV to 208V transformers. Looking at current information, these transformers likely weigh 6500 lbs or so. MDP stands for Main Distribution Panel, yet you are talking about 6500lb MV transformers? That sounds more like a Secondary Unit Substation where your primary is coming in directly from the utility at their local transmission line voltage..

The electrical contractors who toured the facility didn't seem to think that the phases could be separated with a blow torch. Why would that be?
Why would anyone be concerned with "separating phases"? And if you are really asking about a bus duct connection, why do you think they would need to use a (cutting) torch? Are there no bolts?

Would somebody please describe for me the general procedure - and the responsibility of each task - of getting equipment like this out of the building?
As others mentioned, once the power is disconnected, removal from the building is no longer an electrical issue, it's a rigging / grunt work project that would need no input from an EE, other than if they wanted you to consult on the best way to preserve it for possible re-use or resale. If not, call a scrap yard and have them deal with it. The ECs likely don't want to hassle with the grunt work.

...The old equipment has dry type transformers. The new equipment is going into another location. Part of the difficulty is that the new equipment is going in first in a more open location. The new transformers are 480V primaries. The old ones are 13.8KV primaries. The difference in weight for the same KVA is phenomenal. The high voltage according to modern tables are over 6000 pounds. The 480V are only 2000 pounds. (Only and 2000 shouldn't go in the same sentence. )
If the old equipment had 13.8kV primaries and the new equipment has 480V primaries, you are not talking apples to apples, you are talking about the difference between a substation and a distribution transformer (forget the "MDP" completely), so weight comparisons are meaningless. By the way, 13.8kV is not "high voltage", that is "Medium Voltage".
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
The cynic in me says it is more likely that some kind of collusion is responsible for numbers that close. :)
I have seen some very close bids where there was absolutely no collusion of any kind. We had a job that we bid a just over $1 million and we were second by less than $600.
 

growler

Senior Member
Location
Atlanta,GA
So much of this seems odd to me, coming from an electrical engineer...


Well the idea of useing a cutting torch I'm not sure is such a good idea.

If they are thinking to cut the gear into small easy to manage sections. It sounds like this is a closed in area and I'm not sure what would happen if you put a torch to those windings ( a real heavy section). I'm thinking a lot of smoke and fumes that may be hazardous ( the insulation material is going to burn ).

If they are worried about weight then you are right and it could be disassembled into sections that would weigh less than the whole.
 

Fulthrotl

~Autocorrect is My Worst Enema.~
Well the idea of using a cutting torch I'm not sure is such a good idea.

yeah. what on earth for?

if it's being scrapped, a porta band works well for disassembly.
better yet is a battery operated rattle gun.

my first though is.... if they are that old, what's the winding made of?
a 6,000# xfmr would have a couple thousand pounds of copper in it's core.....

so a bank of three of them....

:happyyes: we like copper......


 
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