[RE-wrenches] Long MC Cable Mid String

[Walt Ratterman]

Drake:

 

The voltage lost between the two points is the product of the current
flowing in the wire, and the resistance of that section of wire (times 2
depending on how you figure the distance.).

 

Walt

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Drake
Chamberlin
Sent: Wednesday, April 22, 2009 7:15 AM
To: dkatz at aeesolar.com; RE-wrenches
Subject: Re: [RE-wrenches] Long MC Cable Mid String

 

I have scratched my head on this one before, because it seems that two
terminals bonded together by a wire are essentially the same terminal.  The
theoretical voltage difference on a terminal is zero.  How do we figure a
voltage drop on a wire that has near zero volt potential between the ends of
the wire.  Can we really use the voltage of the entire array to figure the
drop on an interconnect between two modules?   If so, why can we do this?

Thanks,

Drake 



At 07:49 PM 4/21/2009, you wrote:



David,
There will be less than a 1 volt drop in 36 feet of 10 AWG at the 11 amps
you get from the Evergreen modules.  I don't think anyone will notice.
David

David Katz


David Palumbo wrote: 



Does the following series string wiring cause a problem? With  (18)
Evergreen ES-A 205's (low voltage modules 18.4Vmp) in series feeding a grid
tie inverter with a long series connector in the middle of the string.  (2)
Top Of Pole 9 module mounts with the series connection from module #8 on the
first pole to module #9 on the second pole. This MC cable connection would
be, about, 36 feet in length to go 10' down the pole below grade 18" for 13'
and back up the second pole 10' (in conduit all the way) .
 
Will this extra long series wire cause problems?
 
I could use other modules of course but that would raise the cost per watt
by 70 cents.
 
Dave
 
David Palumbo, President
Independent Power LLC
462 Solar Way Drive
Hyde Park, VT 05655
NABCEP Certified
www.independentpowerllc.com 
 

 
 
 
 
 

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Drake Chamberlin
Athens Electric
OH License 44810
CO License 3773
740-448-7328
740-856-9648 

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