Protection of Fire Pump Wiring

[jar546]

In this case you are looking at a service rated fire pump controller and ATS all in one. The conduit on the right comes from the service meter as the ATS acts as the service disconnect. The conduit on the right in the back is for the bond to the metal water piping. The 2 conduits on the left are as follows:

One is the feeder to the fire-pump and the other is the feed from the generator. This fire pump ATS and controller in one combo is split into 2 cabinets with the service conductors being the only connection on the right side.

The fire pump is within this same room and they are not planning on using any fire rated cable assemblies, hence the conduit for the wires. With that being said:

You can see that they have encased the PVC conduit in concrete throughout the room except for the last section that feeds into the fire pump ATS/Controller combo.

What conduit(s) is required to be fully encased in concrete all the way to the bottom of the controller/ATS housing even though the pump is in the same room?

 

[steveray]

I would assume PVC and not RMC......

 

[Builder Bob]

Not correct at all - PVC should not be exposed - conduit should have been encased in concrete minimum of two inches in depth

All conduits including grounding should be encased in concrete.

 

[jar546]

OK let's break this down:

First off, NFPA 70 (NEC), Article 695 covers this but does refer to other articles.

695.6 Supply Conductors is where you want to look first. Let's take a look:



So the above exception tells us that the supply conductors that originate and terminate in the fire pump room such as the load side feeder to the pump itself does not have to be encased. The generator, in this case is not in the same room, therefore those conduits must be encased in concrete.

This then forces us to look at NEC 700.10(D) to see if all of it needs to be encased if they are not using fire rated wiring/cable assemblies