Feed through panel

[clint morgan]

I have a one-line diagram showing a 400 amp main switch feeding 2- 400 amp bussed panel boards. It is showing being fed with 2-2" pipes each carrying 4-3/0 cu. My question is in paralleling 3/0 cu. wouldn't one line be significantly longer than the other causing me a problem? My thinking was to run 1-2 1/2 pipe with 250 mcm cu. feeding then 250 mcm cu. feeding the other panel.
I've always thought that the parallel wires had to be the exact same length or it could cause significant problems. Please advise. The run is 240' away from the main switch, with 2- 90 degree bends in it. Please advise. Thank you, Clint morgan

 

[nakulak]

match mark the conductors before installing them and you can make them exactly the same length. (in reality small differences don't amount to beans IMO.) Not using parallels is always an option - in my case we always use cost to decide.

 

[mcclary's electrical]

I have a one-line diagram showing a 400 amp main switch feeding 2- 400 amp bussed panel boards. It is showing being fed with 2-2" pipes each carrying 4-3/0 cu. My question is in paralleling 3/0 cu. wouldn't one line be significantly longer than the other causing me a problem? My thinking was to run 1-2 1/2 pipe with 250 mcm cu. feeding then 250 mcm cu. feeding the other panel.
I've always thought that the parallel wires had to be the exact same length or it could cause significant problems. Please advise. The run is 240' away from the main switch, with 2- 90 degree bends in it. Please advise. Thank you, Clint morgan

Welcome to the forum. These runs are not actually parallel, one could be a different length than the other with no problem. One could be beside main 400 amp switch, and the other could be 240 feet away without a problem

 

[Ruff-N]

Welcome to the forum. These runs are not actually parallel, one could be a different length than the other with no problem. One could be beside main 400 amp switch, and the other could be 240 feet away without a problem

I agree. I would stick with the diagram.

 

[Dennis Alwon]

I have a one-line diagram showing a 400 amp main switch feeding 2- 400 amp bussed panel boards.

Clint, in order to be parallel the conductors would have to originate and terminate at the same place. This does not sound like what you have.

Caution-- if you are saying you have one 400 amp breaker feedingSomething is wrong here. You cannot have 3/0 copper going to 2 panelboards at 400 amps. Please explain better what you have because what I read is totally illegal.