Fire Pumps - 695.6 (E) Pump Wiring

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SIRSPARKSALOT

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I was recently reading fire pump code section as I have another pump to do. I am curious as to the why EMT raceways cannot be used as an approved method. It states that the following can be used:

RMC
IMC
LFMC
LFNC
MC (with an impervious covering)
MI Cable

I am assuming is has to do with possible water contact. Why would EMT with R/T connectors and couplings not be acceptable? Any thoughts? :?
 
Rigid metal conduit is required from the motor control to the fire pump motor.( this is ussualy located next to it) if i not wrong this is because years ago the RMC had a 1 hr fire rate listed.
Also when you connect the motor most of the time you have to run the pipe across the ceiling amd down next to the pump and change to sealtight or flex, the trader on the rigid make this installation more strong than EMT that the screws can felt down and pipe can be ripped apart.
The 2 hrs fire rate requirements is required only from the load side of the first disconnect switch to the fire pump motor control, in that case one opcion is use a EMT pipe with a fite rate wire as a RHH that is a 2 hrs fire rate cable. Hope this help.
 
DARUSA said:
Rigid metal conduit is required from the motor control to the fire pump motor.( this is ussualy located next to it) if i not wrong this is because years ago the RMC had a 1 hr fire rate listed.
Also when you connect the motor most of the time you have to run the pipe across the ceiling amd down next to the pump and change to sealtight or flex, the trader on the rigid make this installation more strong than EMT that the screws can felt down and pipe can be ripped apart.
The 2 hrs fire rate requirements is required only from the load side of the first disconnect switch to the fire pump motor control, in that case one opcion is use a EMT pipe with a fite rate wire as a RHH that is a 2 hrs fire rate cable. Hope this help.
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The strength and durability of RMC or IMC makes sense - but then they allow LFMC, and LFNMC both of which may be outperformed by EMT for strength and durablilty:?
 
kwired said:
The strength and durability of RMC or IMC makes sense - but then they allow LFMC, and LFNMC both of which may be outperformed by EMT for strength and durablilty:?
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Because LFMC an LFNMC are limited in lenght by the code !!!! 3 feet unsupported and 6 feet supported you can not run LFMC from the motor control to the pump if the leng of the LFMC or LFNMC is longer than 6 feet.
 
DARUSA said:
Because LFMC an LFNMC are limited in lenght by the code !!!! 3 feet unsupported and 6 feet supported you can not run LFMC from the motor control to the pump if the leng of the LFMC or LFNMC is longer than 6 feet.
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Please give us references for that information, I find no limit on length of either raceway, support requirements are a little more complicated than other raceways, and there are limitations on use of LFMC as an equipment grounding conductor, but pull a separate EGC and that is no longer an issue.
 
kwired said:
The strength and durability of RMC or IMC makes sense - but then they allow LFMC, and LFNMC both of which may be outperformed by EMT for strength and durablilty:?
Click to expand...

I'm with kwired on this one, hence the reason for my questions...LFMC & LFNMC allowed but EMT not...this does not make sense. That's why I was thinking maybe it was a water issue.

Also, in regard to the length of LFMC and LFNMC I do not recall any length restrictions as long as it is supported per code and the possible addition of a ground wire when required.
 
kwired said:
Please give us references for that information, I find no limit on length of either raceway, support requirements are a little more complicated than other raceways, and there are limitations on use of LFMC as an equipment grounding conductor, but pull a separate EGC and that is no longer an issue.
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Soory!!! You are right but some times I just keep rules in my mind in order to use every day.
NYC have an amendment to the 350.12, they add a subsection #3 to read as follows.

350.12 Uses not permitted


(3) In lenghts exceding 1.83m (6feet)
 
SIRSPARKSALOT said:
I'm with kwired on this one, hence the reason for my questions...LFMC & LFNMC allowed but EMT not...this does not make sense. That's why I was thinking maybe it was a water issue.

Also, in regard to the length of LFMC and LFNMC I do not recall any length restrictions as long as it is supported per code and the possible addition of a ground wire when required.
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But they now have "raintight" EMT fittings, but don't even ask my opinion if they are necessary compared to the standard compression fitting we used for years in raintight type locations, that is (and has been) for another thread of its own.

Besides I'm willing to bet on typical three phase induction type motor you could submerge it in water and it would keep running. And a fire pump is one of those things you don't really care what the conditions are, you want it to run until it fails if it is being called upon to do its job, that is why there is no overload protection and overcurrent device is supposed to be able to carry locked rotor current indefinately for fire pumps.
 
kwired said:
But they now have "raintight" EMT fittings, but don't even ask my opinion if they are necessary compared to the standard compression fitting we used for years in raintight type locations, that is (and has been) for another thread of its own.
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I remember when they came out. It was like a witch hunt the inspectors were on to find the guy that didn't know about them. At my old shop we installed two pipe runs on the roof. One with standard compression fittings and one with R/T fittings as a test. I should call my old boss and ask how the "inferior" compression fittings are holding up against the "superior" R/T ones.:lol:
 
SIRSPARKSALOT said:
I remember when they came out. It was like a witch hunt the inspectors were on to find the guy that didn't know about them. At my old shop we installed two pipe runs on the roof. One with standard compression fittings and one with R/T fittings as a test. I should call my old boss and ask how the "inferior" compression fittings are holding up against the "superior" R/T ones.:lol:
Click to expand...

My guess is both have had approximately same amount of water inside raceway, but not because of leaking at fittings it is because of condensation within raceway.
 
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