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wiredInUSA - May 2014
20
ire I
- ay 2014
With equipment available in Europe tested
to 1,000 volts DC, regulatory authorities
in the US are beginning to approve the
components that allow 1,000-volt DC
installations, as opposed to a previous
600-volt maximum.
California-based Fresco Solar has just
completed two rooftop installations using
the newly available parts. One is a 102kw
array on the roof of a nine-story office
building in San Jose, and the other is a
440kw array on an industrial building in
Hayward, CA.
“The building departments of both
cities confirmed that these are the first
commercial thousand volt systems they
have plan checked,” said Sean Kenny,
CEO of Fresco Solar. “It was careful
attention to the nuances of the National
Electrical Code that saw us through, that
and the fact that we could show that
the installations were only accessible
to authorized personnel and not to the
public.”
The Hayward solar array uses over 15,000
feet of 1,000V PV wire. “This is half of what
we would have needed at six hundred
volts,” said Mark Jacobi, VP of operations
for Fresco Solar. “And half the complexity.
In both cases we passed inspection first
time which is also a great reflection on our
crews.”
There are over 1,400 panels on the roof
and 15 ABB Power One inverters. The San
Jose installation also uses a distributed
inverter strategy with four similar inverters.
Only the small three-phase 480v AC,
1,000V DC inverters that meet US rules for
grid interconnection make such projects
possible.
1,000-volt rooftop installations