outdoor concrete pads

[mshields]

What governs the size of a concrete pad relevant to the equipment sitting on it? e.g. If you have a pad mounted transformer that's 10 x 10 (let's pretend they come perfectly square), is there any code mandated limitation on how much larger the pad should be. i.e. you could certainly make the pad 10'-6" by 10'-6", but is there anything to prevent you from making it 11 by 11 or 12 by 12? Also does the code have anything to say on the height above grade of the pad?

 

[Npstewart]

I always had to have the pad sized by a structural engineer. The PSI is a function of the footprint of the equipment and the weight. The higher the PSI the thicker is has to be generally and the same thing with the overhang. If the overhang is not sufficient then the concrete will crack at the corners.

 

[mshields]

how about the height of the pad

how about the height of the pad

I believe the code defines somewhere a maximum height for that pad. I would expect it to be somewhere in Article 110 as the work clearance cannot include a large step down. e.g. if your pad extended 12 inches in front of the equipment, you wouldn't want the end of it to be like a small cliff!

It seems to me that 4 inches is the norm, but I'm looking for the code requirement.

Thanks,

Mike

 

[Npstewart]

I know our building code limits the height of equipment to 30". You can have equipment located greater then 30" but you need to provide a railing 42" high.

 

[GoldDigger]

And then presumably working clearance inside the railing unless it is removable?

Tapatalk!

 

[mgookin]

Whose tranny is it? Is it a POCO tranny or the customers?

 

[Npstewart]

And then presumably working clearance inside the railing unless it is removable?

Tapatalk!

If the railing was removed that would defeat the purpose of having the railing. I would say the railing and pad would have to be 36" away on the service side.