1000v accessibility

[augie47]

This may be obvious in the Code ('08 enforcement) and I have overlooked it and it may be a AHJ call.. but input is welcomed (especially Code references)
40kw Solar install. Array has 1000v DC output. Array is accessible at ground level and is located at a poultry farm. The entire farm (chicken houses, etc) is fenced (barbed wire) and behind locked gates. Solar installer is of the opinion that no other fencing or protection is needed. Inspector is of opinion additional protection is needed but would like references besides 90.4.

 

[Smart $]

I suspect that the fence around the entire farm does not deter access to the 1000V equipment by unqualified personnel, and I assume the fence is not at least 7ft high. See 110.31.

 

[augie47]

I suspect that the fence around the entire farm does not deter access to the 1000V equipment by unqualified personnel, and I assume the fence is not at least 7ft high. See 110.31.

I'm not necessarily in disagreement as I am still reading, but it appears that most of that section addresses "live parts". All the live parts are enclosed and locked. The primary exposure is to
1000v PV wire under the array..

 

[SolarPro]

See 690.31(A). The language varies somewhat from cycle to cycle. The 2014 Code reads: "Where PV source and output circuits operating at maximum system voltages greater than 30 volts are installed in readily accessible locations, circuit conductors shall be guarded or installed in raceways." A note in the Handbook clarifies: "Most PV modules do not have means for attaching raceways. These circuits may have to be made 'not readily accessible' by use of physical barriers such as wire screening." See example in photo.

Here are some alternatives to fencing that may be acceptable in this type of scenario:

http://www.millersolar.com/MillerSolar/practices/PV_wiring/Wire_shielding/_Wire Shielding.html

http://www.solarscrim.com/

These are often ad hoc solutions. There are wide variety of materials that could be used, generally in concert with very intentional wire routing and wire management. Form an AHJ's perspective it's kind of an "I know it [is adequately guarded] when I see it" kind of deal.

 

[jaggedben]

Note that 1000V vs. 600V doesn't matter.

 

[Smart $]

I'm not necessarily in disagreement as I am still reading, but it appears that most of that section addresses "live parts". All the live parts are enclosed and locked. The primary exposure is to
1000v PV wire under the array..

The exposed, though insulated wiring is the main concern. See 110.31(C)(1), which stipulates compliance with Article 225... the go to 225.60. It's a bit debatable whether this area qualifies as open land, but could an animal graze there? ...or go to 225.61. Would the area qualify as "Over or under roofs or projections not readily accessible to people"?

 

[Smart $]

Note that 1000V vs. 600V doesn't matter.

Not under 2008 anyway. Under 2014 it could.

 

[Carultch]

This may be obvious in the Code ('08 enforcement) and I have overlooked it and it may be a AHJ call.. but input is welcomed (especially Code references)
40kw Solar install. Array has 1000v DC output. Array is accessible at ground level and is located at a poultry farm. The entire farm (chicken houses, etc) is fenced (barbed wire) and behind locked gates. Solar installer is of the opinion that no other fencing or protection is needed. Inspector is of opinion additional protection is needed but would like references besides 90.4.

Out of curiosity, is this the same project where you were asking about whether EMT is acceptable inside a poultry house?

 

[jaggedben]

Not under 2008 anyway. Under 2014 it could.

Not sure why you think that. The part of 690.31 quoted above says 30V.

 

[Smart $]

Not sure why you think that. The part of 690.31 quoted above says 30V.

Okay. It didn't sink in when I skim read it. :ashamed1:

 

[augie47]

Out of curiosity, is this the same project where you were asking about whether EMT is acceptable inside a poultry house?

Nope Having enough problems OUTSIDE of the chickenhouse
In all probability it's wired in open THWN like most of it's neighbors.

 

[Smart $]

Not sure why you think that. The part of 690.31 quoted above says 30V.

Okay. It didn't sink in when I skim read it. :ashamed1:

Anyway, let's get back to compliance with 110.31, which the general statement says, in part...

For installations other than equipment as described in
110.31(D), a wall, screen, or fence shall be used to enclose
an outdoor electrical installation to deter access by persons
who are not qualified. A fence shall not be less than 2.1 m
(7 ft) in height or a combination of 1.8 m (6 ft) or more of
fence fabric and a 300 mm (1 ft) or more extension utilizing
three or more strands of barbed wire or equivalent. The
distance from the fence to live parts shall be not less than
given in Table 110.31.

And (D) says...

(D) Enclosed Equipment Accessible to Unqualified Persons.
Ventilating or similar openings in equipment shall be
designed such that foreign objects inserted through these
openings are deflected from energized parts. Where exposed
to physical damage from vehicular traffic, suitable
guards shall be provided. Nonmetallic or metal-enclosed
equipment located outdoors and accessible to the general
public shall be designed such that exposed nuts or bolts
cannot be readily removed, permitting access to live parts.
Where nonmetallic or metal-enclosed equipment is accessible
to the general public and the bottom of the enclosure
is less than 2.5 m (8 ft) above the floor or grade level, the
enclosure door or hinged cover shall be kept locked. Doors
and covers of enclosures used solely as pull boxes, splice
boxes, or junction boxes shall be locked, bolted, or
screwed on. Underground box covers that weigh over
45.4 kg (100 lb) shall be considered as meeting this
requirement.