As I follow this thread and just got off a 12 and 12 roof, I wondered
how the fire departments deal with roofs you cannot get to easily?
I've seen lots of photos of firefighers on roofs, but pretty much all
flat roofs or low angle ones.
For example
a metal roof in the wet,
steep roofs
steep
Hi Jay,
You are right. A lot of photos and almost all live shots are from news
helicopters usually showing commercial flat roof fires. Most of the smaller
fires and residential fires are knocked down too fast for reporters to get
to the scene or the news services think are not eye-catching. Mo
Here is an issue that has been bothering me for some time and I finally was
asked to explain it to a junior member of our Company and had to admit
ignorance...
I am referring to the issue of derating the ampacity of wire in a raceway or
conduit with other current carrying wires. I refer to Table B
Peter,
Where do you read the 50% diversity? My 2005 NEC handbook clearly says that
the raceway adjustment table is based on NO diversity--all conductors loaded
at maximum.
Bill.
-Original Message-
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrench
All,
Here is the refuting post by my friend Matt Paiss of the San Jose Fire
Department. Our thanks go out to him for his responsiveness. It is now
posted on the homepage of www.FireFighterCloseCalls.com
FIREFIGHTING AND SOLAR PANELS: FACT VS FICTION
URL: http://firefighterclosecalls.com/fullstor
NEC 2005 Handbook, Annex B, page 1204, Table B.310.11
I see now that 100% diversity applies to 4-6 and 7-9 ccc's but 50% above
that. Sorry.
- Peter
Peter T. Parrish, President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
Ph 323-258-8883, Mobile 323-839-6108, Fax 32
Some of this just puts me to sleep It's a blonde thing, I guess!
-Original Message-
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Peter
Parrish
Sent: Thursday, January 08, 2009 12:01 PM
To: 'RE-wrenches'
Subject: Re:
In any case,I believe "load diversity" refers to the duty cycle of the
various circuits with constant load levels, as opposed to the instant
current flowing in the conductors to any given load.
Mark Frye
Berkeley Solar Electric Systems
303 Redbud Way
Nevada City, CA 95959
(530) 401-8024
www.ber
Peter,
We cannot use load diversity to increase the number of conductors in a PV
conduit since there generally is little diversity among the conductors,
particularly on large arrays.
The more traditional conduit adjustment table to use is Table
310.15(B)(2)(a). The value from this table is multip
Boy did I light one off. Can I steer an enlightened soul back to my specific
question:
"In specific: if we have two DC PV circuits (4 wires: 2 positive, 2
negative) in EMT and we have taken into account the "PV 125% circuit current
calculation", "cable sizing of 125% for proper operation of overcu
I can't speak for larger depts, but we train our folks to always work off roof
ladders -- regardless of pitch. just because rafters can become surprisingly
unstable in a fire. (it takes only 400 F to cause those stamped on metal plates
to warp and fall off prefab rafters). as for firefighter
Hi Jay --What we do for nasty slopes and bad weather is use roof ladders. Firefighters ladder conventionally up to the eaves, one secures the ladder and stands at the top, and a roof ladder is passed up from below. It has big hooks on one end that are designed to hook over the roof peak, and they
I'm curious to hear any horror stories (or simple nuisances) relating to
open field ground mounted arrays involving wildlife. Either wildlife or
array being damaged by the other. The only hassles we've had have been
the occasional squirrel under flush mounted rooftop arrays. We've had a
few grou
Don't forget to tell people to let their rural vfd know where their
inverter disconnects are.
REgards,
Ezra Auerbach
(off grid ex volunteer firefighter.
On 8-Jan-09, at 4:18 PM, Dan Fink wrote:
Hi Jay --
What we do for nasty slopes and bad weather is use roof ladders.
Firefighters l
People and animals have walked into PV ground mounts (and wind tower guy wires)
in the dark. Livestock and wild animals have used arrays and other ground
mounted equipment for scratching posts. Children and others have climbed on
arrays and ground mounted equipment (attractive nuisance). Fences
Hi Bill,
Who puts this into a spread sheet or computer program?
thanks,
jay
peltz power
On Jan 8, 2009, at 11:56 AM, Bill Brooks wrote:
Peter,
We cannot use load diversity to increase the number of conductors in
a PV
conduit since there generally is little diversity among the
conductors
Peter,
No--is that short enough.
Imax is defined by 690.8(A). Imax is the value used for doing all conditions
of use calculations including temperature corrections, conduit fill, and
sunlight impact.
The overcurrent protection device (OCPD) must be sized to 125% of Imax for
continuous operation
We did a pole mount system several years ago for an off-grid home we also designed earlier that had a rooftop array. The pole mount system was an add to expand the existing solar capacity. The pole was the "normal" height that should have been used, but because the ground was so steep then flatt
All,
This message from Matt Paiss shows that the message is getting out:
Bill,
Not only did it go on their homepage, but it got sent out on what they call
their "Secret List", which is not really very secret, as it has a subscriber
base of somewhere near 100,000. Needless to say, my inbox, cell
19 matches
Mail list logo
