, March 28, 2014 1:35 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Busbar 120% rule
Very interesting.
So, it is not a overcurrent risk, but a heat issue that may lead to a
nuisance breaker tripping issue?
On Mar 27, 2014, at 12:46 PM, Dave Click davecl...@fsec.ucf.edu wrote
Lots of supply side connections (not line side taps) here in NY.
Glenn
-Original Message-
From: Troy Harvey tahar...@heliocentric.org
Sent: 4/2/2014 13:40
To: RE-wrenches re-wrenches@lists.re-wrenches.org
Subject: Re: [RE-wrenches] Busbar 120% rule
Thanks Bill, Makes sense to me too
In situations where the supply wires can be tapped, it's reasonable to tap in
as much as 50% of the service rating.
But in California, we mostly seem to have combo meter/main/distribution
services, precluding service taps in most projects.
1) 200 amp service w/ 40 amp * 80%
= 7.68 kW maximum
] On Behalf Of Troy Harvey
Sent: Friday, March 28, 2014 1:35 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Busbar 120% rule
Very interesting.
So, it is not a overcurrent risk, but a heat issue that may lead to a
nuisance breaker tripping issue?
On Mar 27, 2014, at 12:46 PM, Dave
Very interesting.
So, it is not a overcurrent risk, but a heat issue that may lead to a nuisance
breaker tripping issue?
On Mar 27, 2014, at 12:46 PM, Dave Click davecl...@fsec.ucf.edu wrote:
I had a nice response all typed up before rediscovering my original source.
Simple answer:
.
Bill.
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Troy Harvey
Sent: Friday, March 28, 2014 1:35 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Busbar 120% rule
Very interesting.
So, it is not a overcurrent risk
I am wondering about the busbar 120% rule, and if there is any wiggle room in
the 2014 NEC.
Fundamentally I don't understand the 120% rule. If my solar breaker is
installed properly at the bottom of the busbar, and the grid-tie breaker is
installed at the top, and the busbar itself is rated
I had a nice response all typed up before rediscovering my original
source. Simple answer: there's still a thermal load to deal with even
though there's no point on the bus seeing a current above the busbar
rating. I am a linking machine today:
The 120% rule in 2014 is 705.12(D)(2)(3)(b). Ugh. Anyway, the inverter
current is 125 percent of the inverter(s) output circuit current, aka the
minimum OCPD and conductor ampacity value per 705.60(B) and 690.8(B)(1).
This is actually a bit of wiggle room: in 2011 the 120% rule was based on
the
Also in 2014 we get 705.12(D)(2)(3)(c) which should be very useful in
distribution panelboards.
-N
On Thu, Mar 27, 2014 at 3:00 PM, Brian Mehalic br...@solarenergy.orgwrote:
The 120% rule in 2014 is 705.12(D)(2)(3)(b). Ugh. Anyway, the inverter
current is 125 percent of the inverter(s)
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