Electrical Equipment Clearances

[WA_Sparky]

I know the typical clearances for electrical equipment is 30 in laterally, 36in in front of equipment and minimum requirements for above, but what about below?
Say you have to find a space to put a 45KVA transformer and the only available space is in an office. Could you technically have a ceiling mounted transformer and 8' below the bottom of the xfmr you have an office desk, as long as the desk did not extend past the front edge of the transformer? Technically you would not be violating the 3' clearance in front, and 30in side to side would be maintained..

 

[EC Dan]

The wording of 110.26(A)(3) says "The work space shall be clear and extend from the grade, floor, or platform to a height of 2.0 m or the height of the equipment, whichever is greater" so I take that to include all space below the equipment as well, extending out and to the sides of the proper depth and width, respectively. The more important question is whether a transformer is even subject to 110.26(A). I sure wouldn't want to sit below a wall mounted transformer though...

 

[don_resqcapt19]

Most authorities do not see transformers as being covered by the working space rules in 110.26(A). Wall mounted transformers and transformers above a ceiling are common. They are also not in list of equipment that requires dedicated equipment space, 110.26(E).