Customer wants a 100 A panel on the 2ND floor of his garage. There is now an existing 100 A panel on the 1st floor of the garage that is fed from a lateral URD from the main house. It's a #2 three wire URD ALUM, two hots and a neutral. Two grounding electrodes installed at this panel and no other metallic path back to the house. The neutral is bonded to the panel and as far as I can see everything looks good. I plan to feed the 2ND floor panel from a 100 A disconnect in the 1st floor panel with #2 SER ALUM run on the inside of the garage protected from physical damage. The grounding and grounded conductors will be isolated and the bonding screw removed in the new 2ND floor panel. This is the first time I've done this sub panel to sub panel in a remote building and wanted to see if you guys see any holes in my plan. Thanks
panel to panel remote building
- Thread starter malty
- Start date
- Status
Jim W in Tampa
Senior Member
- Location
- Tampa Florida
Sounds fine. Way i see the first panel in garage is as service and not really a sub.
- Location
- Logan, Utah
You won't be able to use Table 310.15(B)(6) for this installation so the #2 aluminum SER cable will need to be protected by a 90 amp circuit breaker if you are not under the 2008 NEC. If you are working under the 2008 NEC then the #2 SER cable must be protected by no more than an 80 amp circuit breaker (Depending on the calculated load).
Chris
Chris
I'm in NY state (2002 nec for residential) I see 310-16 is 90A for #2 ALUM . Table 310-15 (b) (6) is for services AND feeders (#2 ALUM-100A), not just service feeders. Article 100 defines feeders as all circuit conductors between the service equipment, the source of a separately derived system or other power supply source and the final branch circuit over-current device. I'm probably wrong but please tell me how I'm reading this funny. 240-6 has a 90 Amp breaker as a standard size but I'm not sure I've ever used one or if my supplier has one. I suppose I could use #1 ALUM OR # 2 COPPER . I've used #2 SER for 100 amp sub panels before in the same building as the service and have had no problems with my inspectors with it.
2002 Code used the terminology "main power feeder to a dwelling unit".
There was some controversy as to the exact meaning, but subsequent Codes clarified that to mean a feeder that carried "all loads associated with the dwelling unit", so unless your feeder does feed all loads to that dwelling unit, it does not qualify under 310.15(B)(6). Now, You have an opportunity to teach your inspectors :grin:
The garage is not a dwelling unit BUT the 2ND floor that the SER feeds is a dwelling unit and the SER will feed ALL loads to that unit.
Thats a wonderful "challange" for your inspector. Your install might be to Code but the original feeder would not be.
- Status