[RE-wrenches] Grounding detached buildings

[Chris Worcester]

Hi fellow wrenches,

We just inherited a two year old off grid system consisting of a separate
home and a big shop/garage that has a mechanical room and battery room. The
OBFW500 power center feeds a main/meter panel. The two Kohler generators
(25kW LPG & 60kW Diesel) feed a transfer switch that feeds another
meter/mains panel. 

1. The previous electrician didn't run any grounding to the home with the
two service feeds, where there are two separate AC load centers, A 200A main
panel and a 100A subpanel for the overflow. both fed from the inverter
meter/mains panel. We have installed the ground one. Now he is claiming 

"code requires separate grounds on detached buildings. 1. House and garage
are not bonded together , they again have  

separate  ground-rods  as required."

I flat can't find any reference to his statement in the code, and he didn't
say where in the code he is referencing. I quoted NEC 250.50, 250.66 as my
reason to correct the lack of grounding between buildings.

 Can anyone shed some light on this, thanks.

Elsewhere I am removing redundant neutral to ground bonds in both the
generators, the generator meter/main panel the home's 200A main panel, and
leaving the one in the inverter meter/main as the one point of bonding.  We
grounded the generator chassis too.

 

Sincerely,

Chris Worcester

Solar Wind Works
NABCEP Certified PV Installer
Phone: 530-582-4503
Fax: 530-582-4603
 <http://www.solarwindworks.com/> www.solarwindworks.com
 <mailto:chris at solarwindworks.com> chris at solarwindworks.com
"Proven Energy Solutions"

 

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