Wow. OK Ray.
This issue of 100% rated under continious use is interesting. Thanks for
helping me get my head around it.
The exception in 210.19 is certainly explicit. Too bad, for this one
man, the exception in 690.8 is less so.
Mark
On 8/23/2014 10:35 AM, Ray Walters wrote:
The 100% exce
The 100% exception is listed in 2 places:
690.8(B)(1) which sizes the conductor, and 690.9(B) which sizes the OCD.
Article 210 doesn't apply, as that is for branch circuits, not PV source
circuits.
690.8 basically walks you through conductor sizing. 690.8(B) requires 2
calculations one for B(1)
HI Mark,
I"ve been having this discussion with some others.
690.9B I think means that the 2nd 125% is for breaker derating.
I have looked and can't find anywhere in the code about conductors being
derated for continuous use. Other deratings yes, temp, conduit etc etc.
But there are many othe
Ray,
I can't follow you all the way down that path.
Is an insulated wire conductor permitted to be use at 100% of it's
rating under continuous operation? No. The ampacity is reduced and the
conductor must be up-sized. Hence, for a defined load (Isc * 1.25),
under continious operation, the con
use of
the fuse rating or the fuse holder rating though.
Brian Teitelbaum
AEE Solar
-Original Message-
From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On
Behalf Of Ray Walters
Sent: Friday, August 22, 2014 6:14 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Assembl
Most combiner boxes, DC rated breakers, and DC rated fuses and fuse
holders we use today, qualify as assemblies for the 100% exception
(Outback, Midnite, etc.) so you only have to size the OCP by 125% of
short circuit current rating for edge of cloud effects.
Since the conductor is sized bas
Thanks Chris,
It's one of those great things about the solar industry that there is
always more stuff going on than one man can keep track of:
http://www.bentek.com/solar-products/recombiners/circuit-breaker/
> Mark,
> The term "recombiner" to me is an electrical panel used on the AC output
>
Mark,
The term "recombiner" to me is an electrical panel used on the AC output of
multiple inverters to combine their electrical outputs.
That is different to a "combiner" which connects solar strings through
fuses to a busbar for connection to the inverter using one conductor pair.
In grid tied s
Folks,
In looking at a circuit breaker based re-combiner for the first time, I am
now pondering the meaning of the Exception below:
NEC 2014 690.8 (B) Conductor Ampacity. PV system currents shall be
considered to be continuous. Circuit conductors shall be
sized to carry not less than the larger o
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