Relocating an existing 400A single phase panel about 3 feet away

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Cartoon1

Cartoon1

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Location
Florida
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Electrical Engineer
Hello! I have a building that they are expanding (making bigger), currently the building is being fed by a main 400A panel. Unfortunately the architect decided to take the wall where the existing 400A is. So i have to relocate the panel about 3 feet to another nearby wall. What worries me is the existing wiring length is not long enough, what is the best solution for this? we don't want to run new wires for the existing branch circuits. Also, keep in mind the existing panel location currently can not be used as a junction box since that wall is being removed.

thank you
 
ruxton.stanislaw said:
How is it currently wired? E.g. MC, NMC, EMT/Rigid? Please put up some photos if you would, to help inspire us.
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PXL_20240301_140926664.jpg

This wall will be removed. Both panels will have to be relocated. A mix of MC and Rigid conduits. I do plan on providing new panels at the new locations, just worried about the extensions of the existing branch circuits.
 
Cartoon1 said:
I do plan on providing new panels at the new locations, just worried about the extensions of the existing branch circuits.
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Then you'll have to provide a junction box and extend the existing conductors to the new location.
 
infinity said:
Then you'll have to provide a junction box and extend the existing conductors to the new location.
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Would there be an issue in providing a junction box above the ceiling? where the old wall is being removed (where the current electrical panels are).
 
Cartoon1 said:
Would there be an issue in providing a junction box above the ceiling? where the old wall is being removed (where the current electrical panels are).
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Do we know which direction the home runs go, up or down, or both?

The only options are using junction boxes or re-pulling the home runs.
 
LarryFine said:
Do we know which direction the home runs go, up or down, or both?

The only options are using junction boxes or re-pulling the home runs.
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The branch circuit breakers go into the ceiling. I presume put a big junction box above ceiling and extend into the new panel location. I don't see any other way around it.
 
Cartoon1 said:
The branch circuit breakers go into the ceiling. I presume put a big junction box above ceiling and extend into the new panel location. I don't see any other way around it.
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That's a good spot for a junction box. Then you can calculate how many conductors you'll need between the box and the panel. From there you can figure out the number of raceways you'll need also and if derating needs to be applied.
 
LarryFine said:
What abo

What about the feeders?
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The expansion to this building caused the exterior wall where the existing meter is currently (outside) to be relocated also. The main feeders come underground but I'm going to have a new meter with a main disconnect outside and new feeder to feed to the relocated new panel location (above ceiling). The relocated new main panel is going to be main lugs only instead of main circuit breaker now since the building didn't have a main disconnect next to the meter.
 
Cartoon1 said:
The expansion to this building caused the exterior wall where the existing meter is currently (outside) to be relocated also.
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You fixed bid or hourly? It was sooo easy for the architect to slide what wall over in the Chief Architect software.... maybe there was no realization of how difficult and, yes, risky, the MSP move will be.
 
Cartoon1 said:
What worries me is the existing wiring length is not long enough, what is the best solution for this?
Click to expand...
It's time for you to remove all the ceiling tiles and the drywall, and see. I mean you might be lucky and everything feeds from the top, and you can establish a passive splice box at that distance. But the bookmakers in Vegas not going to give much spread there....
 
brycenesbitt said:
You fixed bid or hourly? It was sooo easy for the architect to slide what wall over in the Chief Architect software.... maybe there was no realization of how difficult and, yes, risky, the MSP move will be.
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Bid! A bathroom in place of the existing electrical room is more important to them lol. Once they see the electrical contractor cost, they might reconsider ha
 
brycenesbitt said:
It's time for you to remove all the ceiling tiles and the drywall, and see. I mean you might be lucky and everything feeds from the top, and you can establish a passive splice box at that distance. But the bookmakers in Vegas not going to give much spread there....
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Yup, I plan to get in the ceiling and see if there space up there.
 
Cartoon1 said:
Hello! I have a building that they are expanding (making bigger), currently the building is being fed by a main 400A panel. Unfortunately the architect decided to take the wall where the existing 400A is. So i have to relocate the panel about 3 feet to another nearby wall. What worries me is the existing wiring length is not long enough, what is the best solution for this? we don't want to run new wires for the existing branch circuits. Also, keep in mind the existing panel location currently can not be used as a junction box since that wall is being removed.

thank you
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I guess this is why you leave extra slack before cutting cables? There’s always someone changing things later
 
Little Bill said:
And how would slack help when using conduit?
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If you used schedule 80 pvc you could carefully cut and add extensions as needed. I wasn’t saying this was your fault.

It seems you can’t win either way because if you leave too much slack, people get mad for waste but if you cut it to where you intend to terminate then last minute changes screw up the whole project.


At my company the owner tells us the motors he needs to be powered but after he selects a feeder size and has us install it he later keeps adding more and more loads to it
 
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