ECN Forum
Posted By: BigB Roof Top Inverters - 12/10/13 04:57 AM
Are roof top inverters common? Here in Tucson we have a "solar readiness ordinance" which requires, among other things, a raceway from the panel to the roof top during construction of new SFRs. Since 690.31 requires the DC output to be run in metallic conduit and kept at least 10" below the roof deck, which can be a tough in some of the multi-story sfrs we are doing with interior panels, we would like to use ENT. This would mean the inverter would have to be located on the roof. The other option is to run from the roof to a location outside the building with EMT, then back inside to the panel via ENT. We did this on the last one but it was a royal PITA. Of course no conduit may show on the building.
Posted By: HotLine1 Re: Roof Top Inverters - 12/10/13 02:30 PM
The only thing I have seen to date is micro-inverters.

We (NJ) do not have a solar prep mandate yet, and the majority of solar is installed on existing SFDs.

Yes, some of the conduit installs are not IMHO attractive, but...code compliant. Some are downright ugly, but again MHO.

Posted By: shortcircuit Re: Roof Top Inverters - 12/10/13 04:39 PM
Like John said, micro-inverters are on the roof. Then you can run any chapter 3 wiring method to the roof. But that all depends on your solar prep rules.

Are you still on the 2005 NEC there in Tucson?
Posted By: BigB Re: Roof Top Inverters - 12/11/13 03:15 AM
Originally Posted by shortcircuit
Like John said, micro-inverters are on the roof. Then you can run any chapter 3 wiring method to the roof. But that all depends on your solar prep rules.

Are you still on the 2005 NEC there in Tucson?


No, we adopted both the 08 and 11 in one swoop Jan 1st. Had 2 days of classes.
Posted By: HotLine1 Re: Roof Top Inverters - 12/11/13 03:43 AM
Thinking on this, not knowing the design of a 'future' PV install is tough.

Are there any 'specs' within the solar prep ord.?
Does the Architect of the SFD have anything within the plans?

Are micro inverters common in your area?

Posted By: harold endean Re: Roof Top Inverters - 12/18/13 05:06 AM
Has anybody seen anything about higher voltage PV systems? I heard of a new style which runs voltages around 1000 volts. Only on the roof though, it gets stepped down to (I assume) 480/277 volts on the ground.

I have seen a couple of 480 volt systems, but I don't believe the roof voltage was 1K. I don't remember what It was, I think it was 600 volt.
Posted By: BigB Re: Roof Top Inverters - 12/18/13 03:43 PM
Originally Posted by HotLine1
Thinking on this, not knowing the design of a 'future' PV install is tough.

Are there any 'specs' within the solar prep ord.?
Does the Architect of the SFD have anything within the plans?

Are micro inverters common in your area?



The architect is required to show on the drawings where the solar panels would be placed. If there is no possible place for the solar panels, then nothing needs to be done. If there is space for the solar panels, we are required to provide a raceway from that location to the service panel location. I don't really know how popular micro inverters are here but I know they are not unheard of.
© ECN Electrical Forums