[RE-wrenches] 1000V System Wiring Details

[William Miller]

August:

Most commercial jobs we work have a vertical ladder through a roof hatch or a vertical enclosed exterior ladder.  Being vertical they are not comfortable to climb, so we immediately set up a ladder outside. 

A fair portion of our work is repairing faulty installs. We always seem to find a compelling reason to take the inverters off the roof. The last two jobs were SMA upgrades from 2599s to 5000us inverters which don't fit on the back of a low rack. This is why these units are coming off and this was fresh in my mind when I saw your post. 

Something about making the parts most likely to fail less accessible seems counterintuitive to me. 

William

Miller Solar

> On Mar 27, 2014, at 7:06 AM, August Goers <august at luminalt.com> wrote:
> 
> Hi William,
> 
> I should have clarified that I was speaking about commercial system with
> the Sunny Tripower or Power-One Trio type 1000 V string inverters. Many
> commercial roofs have stairwell access which makes getting the inverters
> up and then later servicing them relatively easy. But, yes, we have also
> used lifts to get inverters on the roof which does add an expense.
> Typically we get the inverters up with the same equipment that we use to
> lift up the modules and racking as you mention below. There is the
> potential maintenance cost issue down the road if they need to be RMA'd.
> Mostly I think it makes sense for larger commercial systems.
> 
> Best,
> 
> August
> 
> -----Original Message-----
> From: re-wrenches-bounces at lists.re-wrenches.org
> [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of William
> Miller
> Sent: Wednesday, March 26, 2014 9:15 PM
> To: RE-wrenches
> Subject: Re: [RE-wrenches] 1000V System Wiring Details
> 
> 
> August:
> 
> What about the expense of servicing and/or replacing roof mounted
> inverters?  There is a very finite limit on the weight that is
> practical/legal to haul up a ladder. Sure it's easy to toss an inverter on
> the roof at the install when there is already a lift in the budget to
> hoist the PV.  Later on your crew might be tempted to slide a replacement
> inverter up the ladder, but this is not always safe or OSHA legal.
> 
> It's at least $400 to bring a scissors lift and a reach lift is about
> $600. Is this really good economics / safety practice?
> 
> William
> 
> 
> Miller Solar
> 
>> On Mar 26, 2014, at 7:31 PM, August Goers <august at luminalt.com> wrote:
>> 
>> . Going forward, we are going to strive to put inverters on the roof to
> minimize the expense of dealing with the 1000 V runs.
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