[RE-wrenches] Square D Disconnects mounted on the slope of the roof.
boB at midnitesolar.com
boB at midnitesolar.com
Mon Nov 11 18:01:14 PST 2013
Robin had a comment on the breaker issue...
I'll just copy and paste since he says it better than I can for this
kind of stuff.
boB
Square D breakers are thermal breakers and are never used on PV
combiners. I am not familiar with any solar applications where thermal
breakers are used on a roof top. They would not be a good choice due to
the high heat on a roof top. Square D thermal breakers are only rated
for 50 volts DC anyway. The solar industry has always used CBI
hydraulic/magnetic breakers up on the roof top for PV combiners. They
come in 150 and 300VDC configurations. Some CBI breakers are also used
for 600VDC disconnects up on the roof. Carling hydraulic/magnetic CX
600V breakers are also used up on the roof for disconnecting combiners.
These breakers will change by about 5% for trip characteristics if laid
on their back. Remember when you mount a breaker facing you and it is
horizontal or vertical, this is still considered the vertical
orientation because the front plane is vertical. PV combiners that use
CBI breakers are made by OutBack and MidNite. There are over 2 million
breakers in the field in all sorts of orientations. No problem with trip
have ever been reported to me. That is a pretty good record. CBI
breakers in the future will be non-polarized in accordance with NEC2014
so they can continue to be used in PV combiners.
On 11/11/2013 2:42 PM, Bill Hoffer wrote:
> Dan
>
> Hydraulic actuated breakers like the Classic Heiniman GJ,used in off
> grid battery based systems ( now made by Carlon and Airpax, since
> Henimans's patent ran out) it is very critical that they be used in
> the vertical position as is marked on the breaker's chassis. I know
> this from experience because I designed and got UL listed the GFI
> breaker ( common tripped GJ breakers with a .5 amp ground circuit,
> common today in many systems ) for Trace engineering and it kept
> failing the UL test for no apparent reason until we discovered the
> technician at UL was testing it on it's back, not in compliance with
> their own UL sticker on the device! Go figure.
>
> But in support of Dan's comment, unless marked on the breaker itself,
> breaker operation is not dependent on orientation. Water proof rating
> of the enclosure is also another matter and the manufacturer should
> have specifics as to the mounting angle that keeps the outdoor rating.
> The angle can be very critical for any box that uses a lip to deflect
> water (NEMA 3R rating) rather than a seal to keep water out at any
> orientation (NEMA 4 or better). That is more of the issue here along
> with the fact that breakers are operating at less than ideal
> temperature ranges for the designed trip levels This would be
> relevant to the Square D disconnect that I am familiar with that uses
> an overlapping lip to get water spary out for it's 3R rating, if it
> was only tested in a vertical position than tiliting it would not be
> within the paramaters of the UL listing.
> Bill
>
>
> On Mon, Nov 11, 2013 at 9:21 AM, Exeltech <exeltech at yahoo.com
> <mailto:exeltech at yahoo.com>> wrote:
>
> Wrenches,
>
> There appears to be some misinformation getting into this thread.
>
> The "trip" mechanism within standard thermal over-current
> protective devices ("OCP devices") is mechanically spring-loaded,
> and is triggered by heat.
>
> Eric mentions below that Square D breakers are tested in a
> vertical orientation only - the implication being that's their
> only "UL certified" position. If this were true, it would imply
> the breakers cannot be used in any other orientation. This would
> potentially limit the Square D OCP market to sub-panels and other
> enclosures where the devices are vertical. Inasmuch as the vast
> majority of panelboards I've encountered in my 40+ years in this
> industry have the breakers stacked horizontally, it would not be a
> wise business decision for the manufacturer to self-inflict such a
> limitation on their product.
>
> This also does not mean any such limitation (real or not) applies
> to all breakers.
>
> By way of example, OCP devices work in a horizontal position,
> stacked "pancake" style in a main panelboard, as well as
> vertically oriented side-by-side in a sub-panel. In either
> orientation, they are in full compliance with UL 489, (UL
> Standard for Circuit Breakers, Switches, and Circuit Breaker
> Enclosures). If an OCP device *was* positionally-sensitive, UL
> Standards require this sensitivity to be noted in the
> documentation accompanying the device. Further to that point, UL
> 489 Section 7.1.1.13 states: "In determining if a circuit breaker
> complies with the test requirements, the device shall be mounted
> or supported as in service and tested under conditions
> approximating those of intended operation, except as otherwise noted."
>
> Mounting position notwithstanding, a greater concern would be the
> ambient temperature of a rooftop location, whereby summer heat
> would tend to make the OCP device more sensitive than necessary,
> potentially causing it to trip at an amperage below that of its UL
> ratings. While a nuisance, a more serious issue arises when
> operating the OCP device in cold ambient conditions, whereby the
> device may allow MORE than its rated trip current to flow.
>
> Per UL 489, OCP devices are tested at either 25C or 40C ambient.
> Again per UL 489, if an OCP device is to be used in ambient
> conditions other than those two ranges, the acceptable temperature
> range for that OCP device shall be marked on the body of the device.
>
> In UL 489, Supplemental Annex, Section 2, Subsection 2.3.3,
> mechanical vibration testing is conducted with OCP devices
> oriented vertically, horizontally, and inclined 30 degrees from
> vertical, with all devices energized up to 200% of the device
> rated current during the testing.
>
> Given the preceding, and per implication of UL 489 testing
> methods, OCP devices are NOT positionally sensitive.
>
> In conclusion, if you DO install a rooftop OCP system, and for
> proper protection, please ensure the OCP devices utilized are
> rated for the worst-case ambient temperatures involved.
>
>
> Regards to all,
>
>
> Dan Lepinski
>
>
>
>
> At 09:33 AM 11/8/2013, you wrote:
>
> Hi Kirpal,
>
> All Square D safety switches are UL tested in the Vertical
> position ONLY, so if someone is trying to install a switch in any
> other position other than vertical, that will be between them and
> the inspector.
>
> Hope this helps.
>
> Eric
> ____________________________________________________________________________________
>
> Eric Bentsen | Schneider Electric | Solar Business | UNITED
> STATES | Technical Support Representative
> Phone: +(650) 351-8237 ext. 001# | Email:
> eric.bentsen at schneider-electric.com
> <mailto:eric.bentsen at schneider-electric.com> | Site:
> www.schneider-electric.com/solar
> <http://www.schneider-electric.com/solar> | Address: 250 South
> Vasco Rd., Livermore, CA 94551
>
>
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> --
> Bill Hoffer
> 161 SE Fourth Ave
> P.O. Box 1823
> White Salmon, WA 98672
> sunengser at gmail.com <mailto:bhoffer at sunergyengineeringservices.com>
>
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