Stand Alone PV System with Underground Enclosure - Code Violations

**Xamacho** · 07-12-18, 01:53 PM

I was called onto an "art project" that has major malfunctions. The major ones being a homemade (unlisted), uncoated ferrous metal, underground enclosure that contains: the inverter, the charge controller, the panel board, and the batteries.

I am very surprised that PV company installed it without saying anything. Maybe they did, but it was installed nonetheless. I was called in two months after it was installed and upon opening up the enclosure, found 4" of standing water at the bottom of it. A GFCI outlet was below water and had tripped, but all the rest of the equipment was above water and appeared to be undamaged.

I am writing an extensive report about the code violations, but could use some help. I am indicating they need a new, listed enclosure.
They need to install the Panelboard above ground (is this a clearance violation, or can I point to somewhere else?).
If the inverter and charge controller are listed for wet locations, are they allowed to be installed underground in the new listed enclosure? My thoughts are NO as there is little ventilation. Where would I find clearances needed for PV equipment.
There are two 12 V Marine Grade batteries in series, and there is a simple 3" vent pipe. I am claiming this is not "sufficient diffusion and ventilation of battery gases to prevent accumulation." Am I wrong on this? Will this 3" vent pipe in this underground enclosure prevent accumulation without an exhaust fan? Are batteries allowed to be installed below ground?

Thanks for anyone's help,

Michael Camacho, P.E.

**ggunn** · 07-12-18, 02:22 PM

Originally Posted by Xamacho

I was called onto an "art project" that has major malfunctions. The major ones being a homemade (unlisted), uncoated ferrous metal, underground enclosure that contains: the inverter, the charge controller, the panel board, and the batteries.

I am very surprised that PV company installed it without saying anything. Maybe they did, but it was installed nonetheless. I was called in two months after it was installed and upon opening up the enclosure, found 4" of standing water at the bottom of it. A GFCI outlet was below water and had tripped, but all the rest of the equipment was above water and appeared to be undamaged.

I am writing an extensive report about the code violations, but could use some help. I am indicating they need a new, listed enclosure.
They need to install the Panelboard above ground (is this a clearance violation, or can I point to somewhere else?).
If the inverter and charge controller are listed for wet locations, are they allowed to be installed underground in the new listed enclosure? My thoughts are NO as there is little ventilation. Where would I find clearances needed for PV equipment.
There are two 12 V Marine Grade batteries in series, and there is a simple 3" vent pipe. I am claiming this is not "sufficient diffusion and ventilation of battery gases to prevent accumulation." Am I wrong on this? Will this 3" vent pipe in this underground enclosure prevent accumulation without an exhaust fan? Are batteries allowed to be installed below ground?

Thanks for anyone's help,

Michael Camacho, P.E.

Let me guess... Marfa?

**Xamacho** · 07-12-18, 04:29 PM

Originally Posted by ggunn

Let me guess... Marfa?

I can neither confirm nor disconfirm that I live and work and my firm's registration address is Marfa.

**don_resqcapt19** · 07-12-18, 04:37 PM

The 110.26 clearances apply to all electrical equipment. While most boxes are not required to be listed products, boxes installed in wet locations are required to be listed. 314.15

**Xamacho** · 07-12-18, 06:39 PM

Originally Posted by don_resqcapt19

The 110.26 clearances apply to all electrical equipment. While most boxes are not required to be listed products, boxes installed in wet locations are required to be listed. 314.15

Thank you Don. My goal is too move all equipment from underground. Assuming this "underground box does not allow the equipment to meet the clearances, no electrical equipment is allowed inside it", is the simplest way I will describe it to owners of the project. However, as a hypothetical question, should the listed underground box be big enough and meet other NEC requirments, then the equipment would be allowed inside? A hypothetical "Equipment Cellar". I know the Battery racks and trays must be made of treated metal or fiberglass, so I also see this being a violation of 480.8 as well.

**don_resqcapt19** · 07-12-18, 07:07 PM

Unless the equipment all faces up and is directly accessible by removing a top cover, I don't know how you could have the required access.

**jaggedben** · 07-12-18, 09:06 PM

You haven't described any code violations, to my knowledge. Of course equipment can be installed below grade, in a basement, for example. And the basement isn't required to be listed. It's unclear if any of the equipment isn't listed for wet locations, although I would guess it is fine for that, with the exception of the batteries. If there isn't any language in the code that requires rooms where equipment is installed to have proper drainage, perhaps there should be, or perhaps someone can point out where it is. There may very well be violations of non-electrical building codes, but I couldn't tell you what. Perhaps there's a working space violation but you didn't give us the box dimensions.

**gadfly56** · 07-12-18, 09:27 PM

Originally Posted by Xamacho

I can neither confirm nor disconfirm that I live and work and my firm's registration address is Marfa.

That's OK, the TBPE answered that question for you.

If the client is resistant to relocation of the affected equipment, how about suggesting a 6P enclosure? Or mount the equipment above ground and have it wrapped in an outer shell resembling, oh, I don't know, maybe a large boulder?

**pv_n00b** · 07-19-18, 02:40 PM

How about a sump pump?

**petersonra** · 07-19-18, 03:12 PM

Originally Posted by Xamacho

I was called onto an "art project" that has major malfunctions. The major ones being a homemade (unlisted), uncoated ferrous metal, underground enclosure that contains: the inverter, the charge controller, the panel board, and the batteries.

I am very surprised that PV company installed it without saying anything. Maybe they did, but it was installed nonetheless. I was called in two months after it was installed and upon opening up the enclosure, found 4" of standing water at the bottom of it. A GFCI outlet was below water and had tripped, but all the rest of the equipment was above water and appeared to be undamaged.

I am writing an extensive report about the code violations, but could use some help. I am indicating they need a new, listed enclosure.
They need to install the Panelboard above ground (is this a clearance violation, or can I point to somewhere else?).
If the inverter and charge controller are listed for wet locations, are they allowed to be installed underground in the new listed enclosure? My thoughts are NO as there is little ventilation. Where would I find clearances needed for PV equipment.
There are two 12 V Marine Grade batteries in series, and there is a simple 3" vent pipe. I am claiming this is not "sufficient diffusion and ventilation of battery gases to prevent accumulation." Am I wrong on this? Will this 3" vent pipe in this underground enclosure prevent accumulation without an exhaust fan? Are batteries allowed to be installed below ground?

Thanks for anyone's help,

Michael Camacho, P.E.

A. Why does the enclosure need to be listed?
B. I don't recall anything in the code about panelboards being required to be above ground.
C. Seems to me the problem is inadequate drainage more than anything else. I don't think you will find much electrical equipment rated for submersion.
D. Clearance is required where you have to be able to work energized.
E. I don't think the vent pipe is an issue. Sealed lead acid batteries don't outgas much.