[RE-wrenches] Landing into a sub-panel without a main service panel, just a main switch

Pekka Laine pekka at photonsolarpower.com
Thu Dec 22 10:34:26 PST 2011


All,

We have been contracted to install a 10kW-ac system into a 45-year old house that has no main service breaker panel, only a 200A fused main switch (Zinsco). There are five 125 A rated sub-panels throughout the house, some of which have 50A & 60A breakers in them.  I have been told that we are not limited to 40 A max. PV as per 690.64 (B) since there is no main bussbar. I have three questions:
1. Can we land 60A into one of these existing sub-panels
2. If not, how would you recommend "tapping" in the old 200 A fused main switch wires?
3. What do you think is the maximum amperage of PV that can be backfed in to this service?

Any other recommendations welcome.

Respectfully,

Pekka Laine

President
Photon Solar Power Inc.
www.PhotonSolarPower.com
Cell. 760-556-8170
Toll Free 888-SUN-ACDC
CA Lic. #933648
NABCEP Certified PV Installer # 032611-174




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