Bottom Fed Switchgear

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Alwayslearningelec

Senior Member
Location
NJ
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Estimator
How are conduits/feeders fed/run to bottom fed switchgear? THrought the slab? Not sure how you would gain entry? Thanks.
 

charlie b

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Staff member
Location
Lockport, IL
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Retired Electrical Engineer
It helps if the precise location of the gear, and the exact model to be installed, can be identified before the slab is poured. Then you can lay out the conduit from the outside of the building to the location of the gear, and pour the concrete afterwards.
 

chris kennedy

Senior Member
Location
Miami Fla.
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60 yr old tool twisting electrician
It helps if the precise location of the gear, and the exact model to be installed, can be identified before the slab is poured. Then you can lay out the conduit from the outside of the building to the location of the gear, and pour the concrete afterwards.

Beau, the following is an example of what Charlie describes. Also note that most if not all the large bottom fed gear I have installed allows side, top and rear entry. This info is also found in the gear specs. Slabbing in the bottom is my preferred method.

DSCN0544.jpg
 

Alwayslearningelec

Senior Member
Location
NJ
Occupation
Estimator
Thanks everyone. What I was really curious was about the outgoing feeders to the loads. If it is bottom fed gear does that mean the feeder feeding the gear and the feeds going out to the loads are bottom fed. It is definetely only bottom fed.....actually then I guess it would be ALL the feeders..incoming and outgoing. THe slab is already poured....existing work.

Thanks..
 

charlie b

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Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
The phrase "bottom fed" only refers to the power source to the gear. Outgoing conduits can leave via the bottom, if you can plan their routing before you pour the concrete. Otherwise, the outgoing feeders will leave via the top of the gear, and that does not alter the fact that the gear was "bottom fed."
 

Alwayslearningelec

Senior Member
Location
NJ
Occupation
Estimator
The phrase "bottom fed" only refers to the power source to the gear. Outgoing conduits can leave via the bottom, if you can plan their routing before you pour the concrete. Otherwise, the outgoing feeders will leave via the top of the gear, and that does not alter the fact that the gear was "bottom fed."

So when you say "refers to power source" you mean the what is feeding the gear. What the gear is feeding....bottom fed doen not apply to??
 

jim dungar

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Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
So when you say "refers to power source" you mean the what is feeding the gear. What the gear is feeding....bottom fed doen not apply to??
We often use terms like Bottom Fed and Bottom Exit, because they are often not the same.
 

iwire

Moderator
Staff member
Location
Massachusetts
I will point out that before making design decisions based on slang like bottom fed, top fed, etc. that you get cut sheets to see the equipments layout.

Some equipment that says 'bottom fed' is virtually imposable / or a code violation / or just poor workmanship to top feed. (Or the other way around as well)
 

SG-1

Senior Member
From one manufacturer's perspective, we call this Bottom Entry or Top Entry. It does not refer to a incoming line or feeder, only the direction the cable enters the gear. This information is important so we know which way to turn the risers that your cables will meet. Side Entry or Back Entry can be accommodated as well.

All this information is on a drawing called a Floor Plan.
 

necnotevenclose

Senior Member
This may be a seperate post, but I'll try here first since the topic is Bottom Fed Switchgear.

I've heard electricians talk about using "conduit bathtubs" or "conduit lobby" under switchgear to bring in conduits when exact entry points may not be know. I've also heard of some AHJ's disliking this method. Is using "conduit bathtubs" or a "conduit lobby" legal per code?
 
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