hi! I have a question regarding fire pumps. So, I am trying to figure out how to supply normal power to a fire pump. I have been looking through the code and am a little confused. For instance, it says that the fire pump can have a separate service or service tapped ahead of the building’s main disconnect. I understand that the utility provides power to the main panel or main disconnect. Is the fire pump’s power supply coming from the main panel or is it coming directly from the utility? Does it mean that that the fire pump’s power supply will be completely separate from the main panel, and is it connected to a separate breaker or is the main panel distributing power to the fire pump just in a different configuration? I am confused on how the fire pump can be supplied by an independent power source and am having a hard time visualizing it. I would appreciate your help!
Fire pump
- Thread starter zaid200
- Start date
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Most fire pumps are fed from a totally separate service. This can be from a separate transformer; tapped from the building transformer; or tapped into the building service ahead of the building service disconnect.
See 695.3(A)(1)
See 695.3(A)(1)
What do you mean by "tapped into building service ahead of the building service disconnect"? The word "ahead" is throwing me off. Does it just mean that the separate service is just ahead or separate from the building service disconnect? So, it is not connected to the main panel then right?
From 695.3
A fire pump shall be permitted to be supplied by a separate service, or from a connection located ahead of and not within the same cabinet, enclosure, vertical switchgear section, or vertical switchboard section as the service disconnecting means. T
A fire pump shall be permitted to be supplied by a separate service, or from a connection located ahead of and not within the same cabinet, enclosure, vertical switchgear section, or vertical switchboard section as the service disconnecting means. T
- Location
- New Jersey
- Occupation
- Journeyman Electrician
It can be "tapped" from the service supplying the building as long as the connection is ahead of the building service disconnect(s). From there those "tap" conductors will feed their own service disconnect which will feed the fire pump controller.
There is a good Standard at
www.nema.org
Application Guide for Electric Fire Pump Controllers
Application Guide for Electric Fire Pump Controllers
- Occupation
- Licensed Electrician
Correct. Ahead means before the main disconnect.
Note the wording says not in same cabinet or section. I'm sure some here have seen more than I but the "tapped" ones I've seen were in the pull section adjacent to the main breaker section or in a c t cabinet
zbang
Senior Member
- Location
- Roughly 5346 miles from Earls Court
The word "ahead" is often used to mean "before", the same goes for "upstream".
"behind" and "downstream" mean "after"
"behind" and "downstream" mean "after"
Suzuki360
Touched by the current.
- Location
- Central Virginia
- Occupation
- Master Electrician
So the purpose is so the fire pump can take priority over other electrical loads and cannot be shut off Inadvertently 4 consume power needed to run the pump. That bar pump takes priority over everything else. They are designed to run at 300% capacity. A literally are designed to burn up before they give out or trip and overload. The purpose of this is said that the firepow will give its dying rather trying to put the fire out and maintain the high water pressure volume to water needed to put out a fire.
Set a lot of electrical switch gas design. Said it that buyer department connection is actually right at the meter, but ahead of the name it's got it. I'm designated connection section. It's also required to be considered outside of the building. Cannot just be ran intermingled with other time. Do it in the wretch it has been tasted. Or ram outside of the perimeter of the building.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Might look like this, the "tap" is connected between the meter section (first section) and the first service disconnect (third section):
Suzuki360
Touched by the current.
- Location
- Central Virginia
- Occupation
- Master Electrician
So the purpose is so the fire pump can take priority over other electrical loads and cannot be shut off Inadvertently 4 consume power needed to run the pump. That bar pump takes priority over everything else. They are designed to run at 300% capacity. Literally are designed to burn up before they give out or trip an overload. The purpose of this is so that the firepump will give its dying breath trying to put the fire out and maintain the high water pressure volume to the water needed to put out a fire.
You will see a lot of electrical switch gear designed so just after the metering section connection is actually right after the meter, but ahead of the main OCP. In a designated connection section. It's feeders are also required to be considered outside of the building. It cannot just be ran intermingled with other raceways and racks. It will either require to be ran outside the footprint of the building or beneath the slab under 4" of concrete encasement.
Obviously there is a lot more that should be added to this but hopefully you get the idea.
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
I bid one many years ago, coming out of the pad mount transformer, running on the outside of the building to the fire pump room to the other side of the building. The contractor that did get the job obviously did not permit it, (most likely) or the inspector did not know what he was doing. They flexed out of the service disconnect enclosure (no pull section) inside the building, ran overhead in the open bar joists ( no firewall) inside thru the sales floor, to receiving where the fire pump room was located!
You will see a lot of electrical switch gear designed so just after the metering section connection is actually right after the meter, but ahead of the main OCP. In a designated connection section. It's feeders are also required to be considered outside of the building. It cannot just be ran intermingled with other raceways and racks. It will either require to be ran outside the footprint of the building or beneath the slab under 4" of concrete encasement.
I believe 695.6 allows feeders to be run inside the building IF they meet specific requirements.
I believe 695.6 allows feeders to be run inside the building IF they meet specific requirements.
- Location
- Illinois
- Occupation
- retired electrician
Actually the requirements in NFPA 20 for the fire pump controller permits the locked rotor overcurrent protective device within the fire pump controller to trip after 3 minute at 300% of motor full load current. Note this is within the fire pump controller and the OCPD on the line side of the controller must carry the locked rotor current forever.
So, the fire pump has its own panel (not connected to the main panel)?
Does this wiring diagram make sense?
Most of the one I have seen have a service directly to the FP controller (no disconnect ahead) and the ATS is built into the FP controller but all, that can vary depending on the particulars of your install.
Thanks! This is just a general diagram that I drew. I guess my question is would this be an appropriate wiring diagram based on all the codes and requirements?
gadfly56
Senior Member
- Location
- New Jersey
- Occupation
- Professional Engineer, Fire & Life Safety
I would say "yes". Make sure that the disconnect ahead of the ATS can carry the locked rotor current for the fire pump. See NFPA 20 for calculation of the locked rotor current; don't use the usual rules of thumb.
As augie47 mentioned, the ATS is usually a combo with the fire pump controller. That way you can be sure that all the particulars are correct since we are dealing with a fire pump, and they are always a bit confusing. You could keep the upstream disconnect if you get a combo controller and ATS, but is also comes with a disconnect built in, so, why bother?
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