Re: [RE-wrenches] Busbar 120% rule

2014-04-03 Thread Phil Forest
, 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

Re: [RE-wrenches] Busbar 120% rule

2014-04-03 Thread Glenn Burt
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

Re: [RE-wrenches] Busbar 120% rule

2014-04-03 Thread William Korthof
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

Re: [RE-wrenches] Busbar 120% rule

2014-04-02 Thread Troy Harvey
] 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

Re: [RE-wrenches] Busbar 120% rule

2014-03-28 Thread Troy Harvey
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:

Re: [RE-wrenches] Busbar 120% rule

2014-03-28 Thread Bill Brooks
. 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

[RE-wrenches] Busbar 120% rule

2014-03-27 Thread Troy Harvey
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

Re: [RE-wrenches] Busbar 120% rule

2014-03-27 Thread Dave Click
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:

Re: [RE-wrenches] Busbar 120% rule

2014-03-27 Thread Brian Mehalic
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

Re: [RE-wrenches] Busbar 120% rule

2014-03-27 Thread Nathan Charles
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)