steve holt
Member
- Location
- Hawaii
If the fire pump controller is listed for use as a service disconnect, does the OCP needs to be based on Locked Rotor Current? The OCP in all controllers that I have seen, are sized based on FLA, not Locked Rotor.
Fire Pump Service Disconnect at Fire Pump Controller
- Thread starter steve holt
- Start date
- Status
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
If it’s a listed assembly, that sizing is all part of the listing. For fire pump service disconnect controllers, the is no OCP, just short circuit and ground fault.
The concept is sacrifice the motor in the event of a fire
The concept is sacrifice the motor in the event of a fire
steve holt
Member
- Location
- Hawaii
Does that mean if it is listed, the breaker is supposed to be sized based on LR?
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
I don’t know, I have only installed 2 fire pump controllers and they were sized by HP, voltage snd phase
hhsting
Senior Member
- Location
- Glen bunie, md, us
- Occupation
- Junior plan reviewer
Hi steve holt inside of the fire pump controller listed device is all NFPA 20.
In NFPA 20 2013 section 10.4.4 says if you have squirrel cage motor as fire pump then the minimum the breaker is set at is 300% of fla of fire pump motor. It also says that the breaker is set to trip between 8 secs to 20 secs at locked rotor current.
Please not minimum 300% can mean different manufacturer can set breaker at 400%, 500% all the up to 600%.
Outside of the fire pump controller listed device if designer choses to place breaker in line side then that breaker is sized per NEC 2017 Section 695 and if utility is source then it is sized based on locked rotor current but this outside breaker will trip after the breaker inside the fire pump controller.
Inside the fire pump controller NFPA 20 2013 section 10.3 top of my head but don’t quote me on that says that breaker inside fire pump controller frame size is 115% of full load amps But this is not where the breaker is set at according to 10.4.4.
Hope that helps
hhsting
Senior Member
- Location
- Glen bunie, md, us
- Occupation
- Junior plan reviewer
Inside fire pump controller listed device breaker is sized and set by the manufacturer you dont touch. If you want to know where it set at contact your manufacturer if it complies per nfpa 20 then see previous thread. But still you dont touch
Last edited:
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Which is what I said in post #2
hhsting
Senior Member
- Location
- Glen bunie, md, us
- Occupation
- Junior plan reviewer
Ahh you bet me to it. I am not fast enough
hhsting
Senior Member
- Location
- Glen bunie, md, us
- Occupation
- Junior plan reviewer
Since you installed 2 fire pump controllers Tom do you know what size equipment grounding conductor lug and incoming phase conductors where? Did the EGC lug came with manufacturer fire pump controller or you provided them?
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Tulsa Electrician
Senior Member
- Location
- Tulsa
- Occupation
- Electrician
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
The first one was in 1999 and the second in 2010. I didn't provide the lugs. Incoming was about 3/0 CU
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Thats a sneaky way to get a question answered from another post
hhsting
Senior Member
- Location
- Glen bunie, md, us
- Occupation
- Junior plan reviewer
Thanks Tulsa. The one in link by Firetrol appears to have no ground lug size?
Tulsa Electrician
Senior Member
- Location
- Tulsa
- Occupation
- Electrician
Here is a good read for you. Directly related to your question.
www.neca-neis.org
Your welcome.
The way I read it your co worker is incorrect, unless you have some kind of an amendment.
Enjoy your read and review applicable code sections.
I know sometimes artical 250 seams to be confusing however don't read more into it than what it says.
Soares is a great source of info on the subject. I would get the book and read thought it. It helped me a lot with artical 250.
It will guide you though the calculations you seek. It also holds the key to your question on 250.122 is set up.
There is a paper that called history of residential grounding. Search this and read. I think you find it interesting. It dates way back as the code was developed.
Here is an insert from the paper. As you read though it you find key items that directly relate to today's NEC code on grounded systems.
I know I like learning so I hope you enjoy.
CQD: 11/28/2014
The way I read it your co worker is incorrect, unless you have some kind of an amendment.
Enjoy your read and review applicable code sections.
I know sometimes artical 250 seams to be confusing however don't read more into it than what it says.
Soares is a great source of info on the subject. I would get the book and read thought it. It helped me a lot with artical 250.
It will guide you though the calculations you seek. It also holds the key to your question on 250.122 is set up.
There is a paper that called history of residential grounding. Search this and read. I think you find it interesting. It dates way back as the code was developed.
Here is an insert from the paper. As you read though it you find key items that directly relate to today's NEC code on grounded systems.
I know I like learning so I hope you enjoy.
Attachments
hhsting
Senior Member
- Location
- Glen bunie, md, us
- Occupation
- Junior plan reviewer
Here is a good read for you. Directly related to your question.
Your welcome.CQD: 11/28/2014
The way I read it your co worker is incorrect, unless you have some kind of an amendment.
Enjoy your read and review applicable code sections.
I know sometimes artical 250 seams to be confusing however don't read more into it than what it says.
Soares is a great source of info on the subject. I would get the book and read thought it. It helped me a lot with artical 250.
It will guide you though the calculations you seek. It also holds the key to your question on 250.122 is set up.
There is a paper that called history of residential grounding. Search this and read. I think you find it interesting. It dates way back as the code was developed.
Here is an insert from the paper. As you read though it you find key items that directly relate to today's NEC code on grounded systems.
I know I like learning so I hope you enjoy.
Thanks will do. By the way do you know what size ground lugs do they have on fire pump motor itself? Is their any sheet for that?
hhsting
Senior Member
- Location
- Glen bunie, md, us
- Occupation
- Junior plan reviewer
Do you know the fire pump ground lug size in those?
- Location
- Illinois
- Occupation
- retired electrician
What difference does it make? If the EGC lug in the fire pump controller won't accommodate the size of EGC being installed, you simply replace the lug.
Doesn't matter, the electrician can supply whatever he/she needs.
You should look into an apprenticeship program to see how things work in the field.
Many times I provided transformer lugs from stock I had on the truck instead of buying an overpriced manufacturers kit.
hhsting
Senior Member
- Location
- Glen bunie, md, us
- Occupation
- Junior plan reviewer
Not fire pump controller the Fire pump itself. Fire pump must have phase lugs as well as EGC lug.
Difference is in listed equipment changing lug may invalidate the listing. Its like changing what manufacturer provided
Contact the manufacturer for your answer.
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