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Thread: Precautions for long run 400 VDC cabling?
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face BY : James Cameron email (remove spam text)



Thanks Stephen.  Your questions are interesting.  ;-)

I've measured the 400V run just now with a pole, and calculate it at
about 45.5 m.

(Half width of the array string is 4.5 m, then about 3 m to get into
trench, then 35 m of trench, then about 3 m to get out of trench to
equipment bay.  Tall trees that we are unwilling to remove are the
cause of 20 m extra trench length.)

Don't know if the four runs will be bundled or separately trenched,
but the layout of the array suggests two trenches in a V or Y shape
would maintain minimum lengths.

System was sized for extended outages; minimum loads for domestic
health; water pump, heat pumps, and cooking.  Export uninteresting,
because of high regulatory compliance costs, low price paid, and no
time of export pricing.  That may change later.  Reposit looks good.

(Grid did nearly collapse last summer; forecast demand above available
generator capacity, and I'm estimating 10% probability of a day long
collapse this summer, and 30% the year after. It is difficult to plan
when so many factors may perturb the system on a whim, and the
perturbations haven't been long term lately.  Call me the leading edge
of the death spiral.)

Array is to be ground mounted on a structural steel frame with
concrete around the verticals.

Two tiers; 18 modules on upper tier, 18 modules on lower tier; about
18 m wide, and 3.3 m from top to bottom.  Fixed orientation to solar
North, and not tracking.

You didn't ask, but I'll also mention the equipment bay is to be
inside the house envelope, to increase the life of the batteries.  We
had some 45°C 10% RH days last summer.

On Tue, Sep 05, 2017 at 04:25:19AM +0000, stephen.forrestTakeThisOuTspamagilent.com wrote:
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