[RE-wrenches] TL inverter with long DC Feeder

[frenergy]

William,

        Just about a week ago I asked Greg Smith at SMA to confirm that it would be appropriate to use THWN-2 in the buried PVC conduit for the DC run from a pole mount array with it's DC disco to the SMA DC disco below their inverter......Just to be sure you're not thinking you have to use PV wire all the way back to the DC disco at the inverter.  He confirmed that THWN-2 used for the run from the array disco was AOK.

        We have been using Midnight discos with touch-safe fuses and clear signage to not disconnect under load.....authorized solar bozos only.

Bill


  ----- Original Message ----- 
  From: William Miller 
  To: RE-wrenches 
  Sent: Monday, October 06, 2014 11:40 AM
  Subject: [RE-wrenches] TL inverter with long DC Feeder


  Wrenches:

   

  We are getting up to speed on using transformer-less inverters.  I have advocated long for the additional safety offered by these inverters but I am realizing the trade-offs with the new technology:  The implementation gets more complicated with the requirement for PV wire, OCPD and disconnecting means for plus and minus and plus providing  Arc Flash rated equipment.

   

  I am currently designing a system that will locate the PV about 400 feet from the residence.  The system will utilize 2 Solectria 5200 watt inverters at the residence.  I would like to provide disconnecting means for the 4 strings at the array, in case of any needed service or excavating.  Preferably I'd like the disconnecting means to be deployable by a lay person (i.e. the gardener).

   

  Finding an 8 pole, arc flash, 600 VDC rated disconnect is not easy.  I could install an Outback 8 circuit combiner with 8 touch-safe fuse holders.  The new combiners have had dead-fronts for a while now.  The gardener needs only to have a Philips screw driver to open this cover.  Any better ideas out there?

   

  Thanks,

   

  William

   

   


  Lic 773985
  millersolar.com
  805-438-5600

   



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