Gear Switch Install

A

Alwayslearningelec

Senior Member
Location
NJ
Occupation
Estimator
So the GC said another electrical sib suggested the following in lieu of temp genertor.

Step 1. De-energize the main gear and disconnect the bars( or whatever they are) from the main bus bar to the existing switch being replaced). Liven up gear. Now the switch being replaced in isolated from main bus bar and not live.
Step 2. De-energize gear and put new bars( or whatever they are called) from main bus bar to where new breaker will be installed. Liven up gear.
Step 3. De-energize gear and install new breaker. Liven up gear.

Done. Is this doable? THanks
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All of those steps require a shutdown with no power to loads for the duration of the work. Is that acceptable?
 
Very few bus bar people will now do any work in a section if the horizontal bus is still energized. Putting insulating blankets over 3000A bus will not leave a lot of room to physically work in the section.

I have seen many of these replacements done in a single 8 hour outage, often over night. Given normal LOTO and restart procedure timings, I can't think 3 outages would make sense.

Replacing Bolted Pressure switches with breakers should be a simple task for an experienced service shop. You might want to touch base with one for their thoughts.
 
The only way to know if you can do that would be by looking at the detailed bus drawings for that gear.
Even with the bus link removed, that may be energized work and require PPE for the incident energy available at that point.
It would make more sense to just turn the source power off, lock it out and install the new breaker.

Has anyone verified that the existing bus connection for the 3000 amp switch will line up with the line side terminals of the new 2500 amp breaker?
 
Personally I would not guarantee that three shutdowns will get the job done because there are too many variables. Those variables can be mitigated by spending some extra money to temp out the existing loads after the 2000 amp OCPD and then there are no time constraints on changing the switch to a breaker.
 
don_resqcapt19 said:
Has anyone verified that the existing bus connection for the 3000 amp switch will line up with the line side terminals of the new 2500 amp breaker?
Click to expand...
I would bet they do not. Custom bussing should be assumed to be needed.
For sure the spacing across the fuses is often greater than the width of a new breaker.
 
don_resqcapt19 said:
The only way to know if you can do that would be by looking at the detailed bus drawings for that gear.
Even with the bus link removed, that may be energized work and require PPE for the incident energy available at that point.
It would make more sense to just turn the source power off, lock it out and install the new breaker.

Has anyone verified that the existing bus connection for the 3000 amp switch will line up with the line side terminals of the new 2500 amp breaker?
Click to expand...
So there are area on the but where the existing 3000A connects. Those HAVE to line up with the line side terminals of the new breakers? If not then what?
 
Alwayslearningelec said:
So there are area on the but where the existing 3000A connects. Those HAVE to line up with the line side terminals of the new breakers? If not then what?
Click to expand...
You need custom fabricated bus assemblies. If those are not designed and on hand prior to starting the project it could take a number of days to have the bus assemblies fabricated.
Some gear manufacturers have crews that do this kind of work and if so, I would sub the breaker change to them.
 
don_resqcapt19 said:
You need custom fabricated bus assemblies. If those are not designed and on hand prior to starting the project it could take a number of days to have the bus assemblies fabricated.
Some gear manufacturers have crews that do this kind of work and if so, I would sub the breaker change to them.
Click to expand...
Yeah, the service shops i have dealt with have bussing trucks/trailers so fabbing simple run backs and extensions is not hard for them.
 
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