Is this allowed by the NEC?

MJSullivan56

I have an Outback FPR-4048 which I hope to commission before the end of the year. My basement space is VERY tight with low ceilings and little wall space (1800's barn). The output will be 60A distributed over 5 critical loads. I hope to double that over the years by adding more batteries and inverters -- for an eventual total output goal of 125A. One layout that would "fit" my space would be to use two small 8"x11" 120V subpanels turned on their sides instead of one "normal" 240V subpanel (see attached illustration). Is this allowed by the NEC?

Thanks
Michael

Dave Angelini

Buy good subpanels that have alot more spaces if you are going to expand. If you have insurance on the structure, you should get it inspected. Without an inspection the insurance can be denied on new electrical work. I have seen alot of that the past few years.

The inspector will tell you what you need for your county. Basements can be an issue also. Batteries, all types need a space to live in that is large. Turning panels on their side is not intended in the design and could easily be rejected.

MJSullivan56

Thanks for the feedback. I absolutely intend on getting everything inspected and doing everything thing to code (hence the original question). These panels I have shown above are UL listed and can be rotated as per the manufacturer. Still leaves the question about the NEC though.

RCinFLA

It should be legal but you need to have separate ground wires to each subpanel case back to main panel and subpanel should have their neutral bus bars floating and brought back to main box.  Don't daisy chain grounds or neutrals.

No relying on metal conduit to common ground boxes.

You also have to meet the current carrying wire current limit and number of current carrying conductors in given conduit sizing.  This is based on per wire heating and ability to dissipate heat within given conduit size and type. There is a section in NEC for this derating and is a bit complicated and confusing.

Just from picture,  you may have a problem with conduit size and number of current carrying wires inside.

MJSullivan56

I was wondering about that. Thanks for the clarification. 

MJSullivan56

So something more like this, correct?

MJSullivan56

BTW, the spec sheet provided by Schneider doesn't suggest any issues with current carrying capacity (see: https://www.se.com/us/en/product/HOM612L100S/load-center,-homeline,-1-phase,-6-spaces,-12-circuits,-100a-fixed-main-lugs,-nema1,-surface-cover/?range=6030-homeline™-load-centers&selected-node-id=41993832826&filter=business-4-low-voltage-products-and-systems&parent-subcategory-id=51210).

There are several 1", 1.25" and 1.5" conduit knockouts provided by Schneider for this single-phase load center. I was assuming I would use 1.5" -- are you suggesting I might need a greater than 1.5" conduit?

Also: I assume PVC conduit would be acceptable for this application -- correct?

Dave Angelini

The reason I asked if it would be inspected is that your county will be able to tell you exactly what they require. Pretty hard to guess and a total waste of your time if you have to do it again. Look for FAQ or a guide on your county website or just call and ask to speak with the Director of the building department. Once you take out a permit they often are very helpful to a taxpayer.

MJSullivan56

In theory you’d be right. However the AHJ here is very anti DIY. I’ll let the licensed electrician that I hire deal with him directly.