[RE-wrenches] PV Basics - Sting Shading

Friends, Help disabuse this old timer of his outdate notions: crystalline modules MPPT tracking inverter a sting of modules operate at max power in full sun shading causes enough cells in the first substring in the first module to go into resistance to the point that the substring "turns off" a

[RE-wrenches] DC circuit breakers in parallel

Hello Wrenches, I am installing a Classic 150 controller in an RV with potential 95 amps output at 12 volts. The customer has a Midnite DIN box and wants me to use it for the controller output. I am out of 150VDC breakers but I have two 60 amp breakers. Is it safe and reliable to use the 2 brea

[RE-wrenches] Sheets of snow vs ice breakers

Hello Wrenches, We are trying to understand what will happen on a fairly steep roof (34 degree pitch) when snow comes off a large array and hits ice breakers on the metal roof. Before the ice breakers were installed on the bottom couple of feet of the roof, the gutters experienced damage fro

Re: [RE-wrenches] DC circuit breakers in parallel

Why not use one of Midnite's new 100 amp din breakers? Jonathan Hill Solar applications engineer Solar Electric Supply 530-559-3781 solar...@solarelectricsupply.com On Feb 27, 2013, at 8:06 AM, "Larry Crutcher, Starlight Solar Power Systems" wrote: > Hello Wrenches, > > I am installing a Clas

Re: [RE-wrenches] Sheets of snow vs ice breakers

Drake, We deal with issues like this in New England all the time. Yes there are times when a large buildup of snow will overshoot the ice breakers. We just had 2'+ of snow and I had one array with a pitch similar to yours where the snow overshot an Alpine Snow guard and ripped half the snow g

Re: [RE-wrenches] DC circuit breakers in parallel

We are installing the system today and I only have 60amp in stock. Customer lives in CA and is leaving today after the installation. Larry Crutcher Starlight Solar Power Systems On Feb 27, 2013, at 9:17 AM, Jonathan Hill wrote: Why not use one of Midnite's new 100 amp din breakers? Jonathan H

Re: [RE-wrenches] DC circuit breakers in parallel

Larry Our 100 amp din rail is essentially 2 breakers in parallel. So in theory the 2 60 amp breakers "Could" work but. My concern would be that they may not be tripped at the same time where they are not internally ganged. I can't say "Go Ahead" but. Ryan -- Ryan Stankevitz Technical Support

Re: [RE-wrenches] DC circuit breakers in parallel

Hi Ryan, There is a pin whole through each handle. If I connect the handles together with a pin, they can only be set or tripped as a set. So will this external "ganging" do the same thing? Thank you, Larry Crutcher Starlight Solar Power Systems On Feb 27, 2013, at 9:44 AM, Ryan wrote: La

Re: [RE-wrenches] DC circuit breakers in parallel

Check out NEC 240.8dbDan BrownFoxfire Energy Corp.Renewable Energy Systems(802)-483-2564www.Foxfire-Energy.comNABCEP #092907-44 Original Message Subject: Re: [RE-wrenches] DC circuit breakers in parallel From: "Larry Crutcher, Starlight Solar Power Systems"

Re: [RE-wrenches] DC circuit breakers in parallel

Larry: The Code requires parallel breakers to be designed for this application (internally ganged). Just using a handle tie does not allow you to use the poles in parallel. Best Regards, John Berdner General Manager, North America SolarEdge Technologies, Inc. 3347 Gateway Boulevard, Fremont CA

Re: [RE-wrenches] DC circuit breakers in parallel

Hi Dan, NEC does not apply to mobile systems. Thus the reason for asking about "safe and reliable" instead of code compliant. Thank you, Larry Crutcher Starlight Solar Power Systems On Feb 27, 2013, at 11:56 AM, wrote: Check out NEC 240.8 db Dan Brown Foxfire Energy Corp. Renewable

Re: [RE-wrenches] DC circuit breakers in parallel

Use a good "pin" to lock them together.  Make sure they can't disengage (lock-tite the hardware, etc.) and you're good to go. Stay warm out there (ha!). Dan --- On Wed, 2/27/13, Larry Crutcher, Starlight Solar Power Systems wrote: From: Larry Crutcher, Starlight Solar Power Systems Subject:

Re: [RE-wrenches] DC circuit breakers in parallel

This is true. They must be internally ganged when tripping. Be aware that these breakers may not be internally ganged when you manually switch them on and off though. That is where the pin comes in. boB On 2/27/2013 11:05 AM, John Berdner wrote: Larry: The Code requires parallel breake

Re: [RE-wrenches] DC circuit breakers in parallel

And perhaps, size each of the conductors for the entire 95 Amps. Dick Ratico Solarwind Electric --- You wrote: Use a good "pin" to lock them together. Make sure they can't disengage (lock-tite the hardware, etc.) and you're good to go. Stay warm out there (ha!). Dan --- On Wed, 2/27/13, Larry

[RE-wrenches] Conductor Sizing for Supply Side Connection

Wrenches, On an upcoming job we have a Xantrex XW4548 interconnecting with a 200A service, and I'd very much appreciate some advice if y'all are willing. Since the inverter output OCPD is required to be 60A we are looking at a supply side connection, and I have two questions: 1.

Re: [RE-wrenches] DC circuit breakers in parallel

Makes me wonder how many dual breakers I have taken the handle tie off and used as singles in the past. It has been several, and none with no internal connections that I could find or notice, with the exception of longer rivets holding them together. Granted it has been a while since I have don

Re: [RE-wrenches] DC circuit breakers in parallel

On 2/27/2013 1:23 PM, bob ellison wrote: Makes me wonder how many dual breakers I have taken the handle tie off and used as singles in the past. It has been several, and none with no internal connections that I could find or notice, with the exception of longer rivets holding them together.

Re: [RE-wrenches] Conductor Sizing for Supply Side Connection

Hi Garrison, In my opinion you only need to size the conductors to the overcurrent protection. Bill Brooks addressed a similar question of mine a few months ago - I've attached the email here. If you do a node analysis (ie see what would happen under both normal operation and fault conditions at

Re: [RE-wrenches] Conductor Sizing for Supply Side Connection

There is an exception in NEC2011 regarding the point of connection. This may not apply, but you could avoid the supply side. 4500W / 240V = 18.75 x 1.25 = 23.4A, well under the 120% rule. reference 705.12(D)(2) Jeremy All Solar CO,USA - Original Message - From: Garrison Riegel T

Re: [RE-wrenches] Conductor Sizing for Supply Side Connection

Thanks August. I couldn't get the attachment to open, but I see what you're saying. You do bring up a good point about the AHJ as well. Few here have seen solar, and fewer are familiar with 690 so anything out of the ordinary usually gets flagged. As Jeremy points out the 2011 NEC would allo

Re: [RE-wrenches] Conductor Sizing for Supply Side Connection

Jeremy, Good point. Even under the 2008 NEC 690.64(B)(2) you can install up to a 40 Amp breaker on the load side as long as it is on the opposite side of the input feed per 690.64(B)(7). Garrison, do you need a 60 A breaker? I haven't used this product myself, but if the continuous output pow

Re: [RE-wrenches] Conductor Sizing for Supply Side Connection

August, The 60A breaker is intended to allow grid power to pass through to the loads in excess of the inverter's stand-alone output. The point of 705.12 (moved in the 2011 NEC from 690.64 (B)(2)) is to differentiate between load pass-through current and sell curre

Re: [RE-wrenches] Conductor Sizing for Supply Side Connection

Alan, Thanks for the clarification. I believe you and Jeremy are talking about the exception listed on the last paragraph of 705.12(D)(2). I've never used that rule but it is good to know about. When we do battery backup we typically route the critical loads through an external transfer switch r

Re: [RE-wrenches] DC circuit breakers in parallel

Larry: I was tempted to advise against this. I see a similar concept with people trying to parallel PV feeds and then putting two charge controllers at the destination. Not good. However, I see many 200 amp main breakers that are 4 100 amp breakers ganged, with two for each phase. I can n