I am changing out a 3 phase 100 amp panel fed with #2 aluminum. It has 30 circuits and the only way to change it is to upgrade it to a 200 amp to cover the circuits since they don't make a 100 amp with that many circiuts in it anymore. They do make a 125 amp with 12 circuits or 150 amp with 24 circuits which I would have to use twins on.
The problem is, can I upgrade to a 200 amp panel with only #2 aluminum feeders?
Use a 200A panel with a 100A main circuit breaker.
As far as I know, you can do this. However, check the lugs on the new 200 amp panel to make sure that the wire that you connect to them is in the listed range of acceptable wire sizes.
Also, if that #2 aluminum wire is being protected by a 100 amp breaker, change that breaker to 90 amps.
Tom, why do you say to change the breaker to 90? Since this is a service or feeder, not a branch circuit, the code allows #2AL for 100 amps.
[This message has been edited by Electric Eagle (edited 07-31-2003).]
Table 310.15(B)(6) only applies to 120/240 volt 3-wire single-phase dwelling services and feeders.
If the terminations on both ends of this #2 AL are rated for 75C the 75C column can be used which shows that ampacity as 90 amps. If the terminations on either end are only rated for 60C conductors then the 60C column must be used which shows the ampacity as 75 amps.
[This message has been edited by caselec (edited 07-31-2003).]
nevermind
[This message has been edited by Electricmanscott (edited 08-01-2003).]
Electricmanscott, what does that mean?
I wrote something, then I read the question again. I gave the wrong info. Missed the three phase part. Anyway I would go with the 200 amp panel and back feed a breaker if the lugs can't be used. I think you will have to go with the 90 amp breaker anyway. I assume that this will be enough for the loads to be served?
Ya, may have to do that. I put an amp clamp on one leg and it was drawing 80 amps, panel is maxed out. Maybe I can use a 200 amp panel without the 90 or 100 amp main since it is fused at the main disconnect.