Fire pump conduit-Concrete encasement

[Ithinkimstillhere]

I have a new service entrance rated switchboard in the basement of a historical structure. The basement is completely exposed. The service meter is internal to the board and a fire pump is connected ahead of the main breaker. In my documents I indicated that the conduit needs to be concrete encased from the termination at the switchboard, all the way to the fire pump (unless its ran outside-which is impossible).

Contractor is stating that it's impossible for them to concrete encased conduit in the ceiling space of the basement and asking if they can just run RMC. As I understand it, given we can't physically run these conduits outside, they have to be concrete encased, unless I'm missing something here.

 

[hillbilly1]

Doesn’t have to be encased in concrete, just needs to be totally enclosed in a fire wall, which can be of a fire rated material.

 

[don_resqcapt19]

Doesn’t have to be encased in concrete, just needs to be totally enclosed in a fire wall, which can be of a fire rated material.

It appears to me that these are service conductors in the building beyond the point of entrance, so 230.6 will apply.

230.6 Conductors Considered Outside the Building.
Conductors shall be considered outside of a building or other structure under any of the following conditions:

• (1)Where installed under not less than 50 mm (2 in.) of concrete beneath a building or other structure
• (2)Where installed within a building or other structure in a raceway that is encased in concrete or brick not less than 50 mm (2 in.) thick
• (3)Where installed in any vault that meets the construction requirements of Article 450, Part III
• (4)Where installed in conduit and under not less than 450 mm (18 in.) of earth beneath a building or other structure
• (5)Where installed within rigid metal conduit (Type RMC) or intermediate metal conduit (Type IMC) used to accommodate the clearance requirements in 230.24 and routed directly through an eave but not a wall of a building

 

[hillbilly1]

It appears to me that these are service conductors in the building beyond the point of entrance, so 230.6 will apply.

But if a service disconnect is installed at the main tap, then it becomes a feeder, and should only require a fire rated cover?

 

[infinity]

Just run Vitalink 2-hour rated cable.

VITALink® MC 2-Hour Fire Rated Power Cable Cable #VLH1_101108 | OmniCable

www.omnicable.com

 

[don_resqcapt19]

Just run Vitalink 2-hour rated cable.

VITALink® MC 2-Hour Fire Rated Power Cable Cable #VLH1_101108 | OmniCable

www.omnicable.com

I don't see that as being permitted if these are service conductors.

 

[don_resqcapt19]

But if a service disconnect is installed at the main tap, then it becomes a feeder, and should only require a fire rated cover?

The OP says it is connected ahead of the main breaker. 695.3(A)(1) requires the fire pump to be connected on the line side of the building service disconnect, or requires it to be supplied by a separate service.

 

[infinity]

The OP says it is connected ahead of the main breaker. 695.3(A)(1) requires the fire pump to be connected on the line side of the building service disconnect, or requires it to be supplied by a separate service.

That's typically done by "tapping" the line side of the switchboard which would require a service disconnect grouped with the other service disconnects. From the the service disconnect to the pump room there would be no service conductors so a 2-hour rated cable assembly can be used.

 

[hillbilly1]

The OP says it is connected ahead of the main breaker. 695.3(A)(1) requires the fire pump to be connected on the line side of the building service disconnect, or requires it to be supplied by a separate service.

But still can have its own service disconnect at that point.

 

[Joethemechanic]

THHN in ridgid?

 

[infinity]

THHN in ridgid?

Needs to be in a 2-hour rated enclosure. We've done it before. The carpenter encloses the RMC in core board and Sheetrock to achieve the 2-hour rating.

 

[augie47]

If it's service it appears the follwing applies:

695.6 (A) Supply Conductors. (1) Services and On-Site Power Production Facilities.
...............................................Where supply conductors cannot be physically routed outside of buildings, the conductors shall be permitted to be routed through the building(s) where installed in accordance with 230.6(1) or (2).

230.6

• (1)Where installed under not less than 50 mm (2 in.) of concrete beneath a building or other structure
• (2)Where installed within a building or other structure in a raceway that is encased in concrete or brick not less than 50 mm (2 in.) thick

Feeders are more lenient

 

[don_resqcapt19]

That's typically done by "tapping" the line side of the switchboard which would require a service disconnect grouped with the other service disconnects. From the the service disconnect to the pump room there would be no service conductors so a 2-hour rated cable assembly can be used.

I see that as an addition set of service entrance conductors and there is no requirement that the service disconnects for one set of service entrance conductors be grouped with the service disconnects for the other set(s) of service entrance conductors.

 

[augie47]

I see that as an addition set of service entrance conductors and there is no requirement that the service disconnects for one set of service entrance conductors be grouped with the service disconnects for the other set(s) of service entrance conductors.

Agree.. In fact, in 695.3(B) it actually asks that the FP service disconnect not be grouped...
(4) Be located sufficiently remote from other building or other fire pump source disconnecting means such that inadvertent operation at the same time would be unlikely.
as does 230.72(B)
(B) Additional Service Disconnecting Means. The one or more additional service disconnecting means for fire pumps, emergency systems, legally required standby, or optional standby services permitted by 230.2 shall be installed remote from the one to six service disconnecting means for normal service to minimize the possibility of simultaneous interruption of supply

 

[Ithinkimstillhere]

If it's service it appears the follwing applies:

695.6 (A) Supply Conductors. (1) Services and On-Site Power Production Facilities.
...............................................Where supply conductors cannot be physically routed outside of buildings, the conductors shall be permitted to be routed through the building(s) where installed in accordance with 230.6(1) or (2).

230.6

• (1)Where installed under not less than 50 mm (2 in.) of concrete beneath a building or other structure
• (2)Where installed within a building or other structure in a raceway that is encased in concrete or brick not less than 50 mm (2 in.) thick

Feeders are more lenient

Agree.. In fact, in 695.3(B) it actually asks that the FP service disconnect not be grouped...
(4) Be located sufficiently remote from other building or other fire pump source disconnecting means such that inadvertent operation at the same time would be unlikely.
as does 230.72(B)
(B) Additional Service Disconnecting Means. The one or more additional service disconnecting means for fire pumps, emergency systems, legally required standby, or optional standby services permitted by 230.2 shall be installed remote from the one to six service disconnecting means for normal service to minimize the possibility of simultaneous interruption of supply

The fire pump doesn't have a service disconnect on the normal side. Does this mean that IF i install a disconnect, I can consider the conductors as "Feeders" and use 2hr rated assembly in lieu of concrete?

 

[don_resqcapt19]

Agree.. In fact, in 695.3(B) it actually asks that the FP service disconnect not be grouped...
(4) Be located sufficiently remote from other building or other fire pump source disconnecting means such that inadvertent operation at the same time would be unlikely.
as does 230.72(B)
(B) Additional Service Disconnecting Means. The one or more additional service disconnecting means for fire pumps, emergency systems, legally required standby, or optional standby services permitted by 230.2 shall be installed remote from the one to six service disconnecting means for normal service to minimize the possibility of simultaneous interruption of supply

And exception #5 to 230.40 sends you to 230.82(5). The combination of these two rule makes the fire pump conductors an additional set of service entrance conductors and requires them to be installed as service conductors.

 

[augie47]

The fire pump doesn't have a service disconnect on the normal side. Does this mean that IF i install a disconnect, I can consider the conductors as "Feeders" and use 2hr rated assembly in lieu of concrete?

It doesn't make sense to me but that is how I read it. I would appreciate input from others.

 

[don_resqcapt19]

The fire pump doesn't have a service disconnect on the normal side. Does this mean that IF i install a disconnect, I can consider the conductors as "Feeders" and use 2hr rated assembly in lieu of concrete?

NFPA 20, which is the controlling document for fire pumps says that a feeder can only originate at a service that is dedicated to the fire pump.

9.2.2
The normal source of power required in 9.2.1 and its routing shall be arranged in accordance with one of the following:

• (1) Service connection dedicated to the fire pump installation
• (2) On-site power production facility connection dedicated to the fire pump installation
• (3) Dedicated feeder connection derived directly from the dedicated service to the fire pump installation
• (4) As a feeder connection where all of the following conditions are met:
  • (a) The protected facility is part of a multibuilding campus-style arrangement.
  • (b) A backup source of power is provided from a source independent of the normal source of power.
  • (c) It is impractical to supply the normal source of power through the arrangement in 9.2.2(1), 9.2.2(2), or 9.2.2(3).
  • (d) The arrangement is acceptable to the authority having jurisdiction.
  • (e) The overcurrent protection device(s) in each disconnecting means is selectively coordinated with any other supply side overcurrent protective device(s).
• (5)Dedicated transformer connection directly from the service meeting the requirements of Article 695 of NFPA 70