Underground Work

[mstrlucky74]

So have a job were a lot of the dist. equipment is on the slab on grade. They are running the MV feeders underground to the substation as you can see but all the other conduits feeding the slab on grade dist. equipment is run overhead. And there is a lot more than what you see in the pic. They are looking for VE ideas and someone mentioned to me why don't we run all the conduits contained within slab on grade switchgear rooms underground. Is there any reason why you wouldn't do that and just stub-up into the equipment? Why wouldn't they design/show it that way as they do the MV conduits.

 

[gadfly56]

So have a job were a lot of the dist. equipment is on the slab on grade. They are running the MV feeders underground to the substation as you can see but all the other conduits feeding the slab on grade dist. equipment is run overhead. And there is a lot more than what you see in the pic. They are looking for VE ideas and someone mentioned to me why don't we run all the conduits contained within slab on grade switchgear rooms underground. Is there any reason why you wouldn't do that and just stub-up into the equipment? Why wouldn't they design/show it that way as they do the MV conduits.

There is a limit as to how much you can run in a slab without compromising it. Under the slab should be fine. The usual issue is how sure are you as to the brand and location of each and every piece of distribution equipment so you can be sure the stub ups are in the right place? If there is high confidence on those two issues, I'd say go for it.

 

[mstrlucky74]

There is a limit as to how much you can run in a slab without compromising it. Under the slab should be fine. The usual issue is how sure are you as to the brand and location of each and every piece of distribution equipment so you can be sure the stub ups are in the right place? If there is high confidence on those two issues, I'd say go for it.

Thanks. What do you mean by the brand? Eaton, GE etc.? Why does that matter? Affects where conduits come up in gear?

 

[gadfly56]

Thanks. What do you mean by the brand? Eaton, GE etc.? Why does that matter? Affects where conduits come up in gear?

How would it not? Maybe everybody puts all the stub ups in the same place; I don't do gear. However, this is the sort of thing where you absolutely can't afford to be left holding the bag if there is a screw up.

 

[sameguy]

How would it not? Maybe everybody puts all the stub ups in the same place; I don't do gear. However, this is the sort of thing where you absolutely can't afford to be left holding the bag if there is a screw up.

Who supplies the gear, you? If you then you will have/get the locations for your gear. No not all gear is the same, you need to know where the bracing is etc. Remember to leave room for bushings in your layout. Your pipes could go deep like 10' so remember that when counting wire footage.

 

[mstrlucky74]

thanks