[RE-wrenches] Code reference needed

[Dave Click]

At a Xantrex training once upon a time, they explained that the three 
foot minimum height was to keep the unit out of reach of a typical lawn 
sprinkler. I don't know of an NEC reference for any minimum height required.

Peter Parrish wrote:
> I spent some time putting together information on the "2'-6" Lower Limit"
> and the "6'-6" Upper Limit" for operable equipment; and then when I went to
> send out the results of my efforts, the content in the email disappeared.
> Since the information I thought would be helpful, I have re-assembled the
> information. I also found the 6" depth of working space citation. Here goes.
>
>
> First, there has been a pretty complete move to metric units in the NEC
> a/k/a "SI or metric Units". In some places in the NEC, distances are defined
> in terms of meters and decimal fractions of meters, in other places they are
> defined in terms of millimeters, and in some others, they remain defined in
> terms of feet and inches. So the oft mentioned 6'-6" (1.98 meter) limit has
> occasionally been redefined to be 2.0 m (or 6'-6.7" and rounding up becomes
> 6'-7"). However, in many other sections of the NEC designates 2.0 m as 6-1/2
> ft; go figure.
>
> 600 V or less:
>
> Height of working space (headroom) is 2.0 m (6-1/2 ft) or height of
> equipment. Reference is 110.26(A)(3) "Height of Working Space", which in
> turn refers to 110.26(E) "Headroom", with some exceptions.
>
> Depth of working space 150 mm (6 in.). Reference is 110.26(A)(3) "Height of
> Working Space".
>
> Overcurrent Protection needs to be "readily accessible" and the "center of
> the grip of the operating handle" be no more than 2.0 m (6'-7"). Reference
> is 240.24(A).
>
> Switches: "center of the grip of the operating handle" be no more than 2.0 m
> (6'-7") above floor or working platform. There are some exceptions for fused
> switches and circuit breakers on busways, motor switches; and there is a
> exception for "Hookstick operable switches".
>
> Inverters. I have data on SMA, Xantrex and Fronius.
>
> SMA: The Sunny Boy must be mounted so that there is at least eight inches of
> clearance around the Sunny Boy. The clearance between the inverter or the
> SMA DC-Disconnect (if applicable) and the ground has to be at least 3 ft.
> Sunny Boy Installation manual (Ver. 2.2, 2008) p. 26.
>
> Xantrex: Table 2-2 Inverter Clearance Requirements Location Minimum
> Clearance
> Above 300 mm (12 inches) Below There is no clearance requirement between the
> bottom of the inverter and the ground. Front 300 mm (12 inches) minimum. 910
> mm (36 inches) are recommended for easy access for reading the display,
> avoiding accidental contact with hot surfaces, and servicing the inverter.
> Sides Units can be mounted side by side with no clearance between them, but
> 150 mm (6 inches) of clearance around the outside edges of the outermost two
> units is recommended. In hot climates, some clearance between units may be
> needed to prevent thermal derating. Xantrex Grid Tied Owner's Manual,
> December 2009, Revision D, p. 2-7.
>
> Fronius: To get the most out of your FRONUS IG unit, observe the following
> rules... Only install it on a solid vertical wall at a minimum of 3 ft. (0.9
> m) above
> the ground and to a maximum of 6.5 ft. (2 m). Operating instructions
> Grid-connected inverters for photovoltaic systems 02/2008.
>
> I, too, can't find the 2'-6" lower limit specified anywhere in the NEC 2008.
>
> Peter T. Parrish, Ph.D., President
> California Solar Engineering, Inc.
> 820 Cynthia Ave., Los Angeles, CA 90065
> CA Lic. 854779, NABCEP Cert. 031806-26
> peter.parrish at calsolareng.com
> Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885
>
>
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