Comms/Power Vaults

FaradayFF

Senior Member
Greetings,
Does anyone know reasoning behind why an underground concrete duct bank comes into two separate vaults/MHs before entering a building? Since we typically run one duct containing communications and power conduits, why would we have two separate vaults? Why not have a single vault?

I was just curious, this seems like a standard industry practice.

Thanks,
EE
 

hbiss

EC, Westchester, New York NEC: 2014
I've not seen "ducts within a duct", normally power and communications conduits are run separately around here at least. I would hazard a guess and say that the answer to your question is that the conductors/cables emerge from their conduits in the vaults so separate ones are needed to separate power from LV? Dunno, I've never see what you are talking about.

-Hal
 

FaradayFF

Senior Member
I meant that there is a separate vault/PB for electric conduits and communications conduits. Even if the said conduits are part of the same concrete encased duct bank. When these conduits emerge into their separate pull boxes before entering a building, power and comms conduits are not routed through a shared pull box.

Thanks for your replies.
 

Hv&Lv

Senior Member
I meant that there is a separate vault/PB for electric conduits and communications conduits. Even if the said conduits are part of the same concrete encased duct bank. When these conduits emerge into their separate pull boxes before entering a building, power and comms conduits are not routed through a shared pull box.

Thanks for your replies.
Didn’t think they were supposed to be...
 

hbiss

EC, Westchester, New York NEC: 2014
Aren't they run in separate conduits within the concrete encased ductbank? Don't the cables or conductors emerge from those conduits in the pull boxes? You do realize that you can't have line voltage and LV in the same enclosure. Or is there something I'm missing?

-Hal
 
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