Any thoughts on how to flash a copper pipe roof penetration on a metal
roof. The brazed copper flashing we typically use would cause
corrosion with the steel roof I'm afraid. WHat have others used in
this situation?
Troy Harvey
---------------------
Heliocentric
801-453-9434
[EMAIL PROTECTED]
On Dec 10, 2008, at 11:07 AM, R. Walters wrote:
I have a volt drop spreadsheet on our website as well at
http://www.solarray.com/TechGuides/TGmain_T.php
It uses NEC temp correction for resistance, and another temp
correction for ampacity. One is based on ambient air temp, and one
is wire temp. All calculations are taken directly from the 2005
NEC( don't think wire changed in 2008) Also, it lets you look at
various wires at the same time like William's. I don't currently
have AC on it, but it's getting cold here, so maybe I'll add that
this winter.
I hid the ampacity stuff I attempted, since NEC has so many factors
to consider, but its still on there, if you unhide all the rows. I
also tried to do a sizing based on wire cost thing, but when wire
pricing shot up, it threw all that off too.
You can still use that, you just have to enter your per ft cost for
each wire size. The idea was to not spend $1000 putting in 4/0 cable
to save $100 worth of solar power.
Ray
On Dec 10, 2008, at 8:16 AM, Wind-sun.com wrote:
The NEC values are for 75C, but not everything operates at that
temperature (167F), nor or all uses of wire under NEC codes. I
understand why the spreadsheet is set up for NEC since that covers
probably 98% of all uses.
At room temperature (25C), the resistance values are almost 20%
less - the "standard" physics value of #10 AWG is almost exactly 1
ohm per 1000 feet at 26C.
http://en.wikipedia.org/wiki/American_wire_gauge
..................................................................................................
Northern Arizona Wind & Sun - Electricity From The Sun
..................................................................................................
----- Original Message ----- From: "William Miller" <[EMAIL PROTECTED]
>
To: "RE-wrenches" <re-wrenches@lists.re-wrenches.org>
Sent: Tuesday, December 09, 2008 11:48 PM
Subject: Re: [RE-wrenches] voltage drop
Dear Wind & Sun:
What "standard" are you referring to? We are using the 75C values
from the NEC in order to assure code compliance. We need to have
a direct link to the NEC in case of compliance or liability issues.
Thanks for asking.
William Miller
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R. Walters
Solarray.com
NABCEP # 04170442
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