Fire Pumps Overcurrent Protection

[rikcoop]

For Fire Pump Overcurrent Protection I believe that we can use Magnetic Breakers, which provide a disconnecting means and short circuit protection only, for the main disconnect.

Can anyone confirm this for me. I have two jurisidictions with conflicting opinions.

 

[roger]

What is the negative jurisdiction using to turn this down? As long as 695.4(B) (especially 695.4(B)(2)) is followed there is no problem.

Roger

 

[don_resqcapt19]

Are magnetic only breakers listed for use where not part of a combination starter?
Don

 

[ron]

You'll find that most molded case switches are magnetic only breakers. They have an instantaneous (magnetic) characteristic for self preservation .

 

[don_resqcapt19]

Ron,
I never knew that...I thought that a molded case switch was just a switch.
Don

 

[Pierre C Belarge]

Ron
Like Don, your post caught me by surprise. I know you are very good at what you do, but are you sure that the molded case switch also have magnetic breaker capabilities?

I will see what I can dig up, if that is true, we learn something new each day.

 

[frenchelectrican]

Ron;
Even so some breaker case are just switch but i try to grasp your words to my coffee mug. [ excuze moi pour a min ]

what case size are you refering i know few name brand breaker the smaller one dont have any OCPD in there but that part it caught me off guard for a min i guess i going have to look at one of my master catalog book to confermed this scoop about the breaker sans OCPD.

but is that common with most namebrand breakers or just a handfull specal items ??


Thanks for getting my attetion on this one Ron


Merci, Marc

 

[ron]

As an example, the GE Spectra molded case switch on Page 13 of the PDF below
http://www.geindustrial.com/publibrary/checkout/38652.30055.1824.57077/PDF/GET-7002C1.pdf
indicates that the instantaneous setting is fixed and approx 10-12 times the ampacity.
It is essentially the same for almost every MCS except for some large low voltage power breakers which act as a MCS, and have a very low withstand rating.

 

[ron]

Here's the one for Square D on page 145
http://ecatalog.squared.com/pubs/Circuit%20Protection/Molded%20Case%20Circuit%20Breakers/Current%20Limiting%20Molded%20Case%20Circuit%20Breakers/KIL/0601CT9101R12_03.pdf

 

[ron]

Not to belabor the point but here is the last one I used from Siemens http://www.sea.siemens.com/circuit/product/circuitbreakers/MG_Cut-Sheet.pdf on the bottom right of page MG-2

 

[frenchelectrican]

Ron :

thanks for the head up i did look at it what you provide the link and compared to my master catalog book.

yes you are right and i did learn something new along the way.


thanks for getting my and other attetion as well


Merci, Marc

 

[mshields]

Fire Pump Protective device

Fire Pump Protective device

Did I read that most molded case breakers are magnetic only. Not true. Most molded case breakers are thermal magnetic. The thermal is for overload. Magnetic is for short circuit.

Also, where as the code allows you to provide a mag only breaker for a fire pump, try getting a service rated switchboard (which the the fire pump disconnect needs to be with a Magnetic only breaker). You can't do it because UL won't allow it. So you always end up getting the thermal mag. Of course, if sized per the locked rotor amps, the thermal is so high as to not be a factor.

 

[McDowellb]

The service disconnecting means where required shall have overload protection 230.90. 230.90 (A) exception no.4 overload protection for fire pumps supply conductors shall conform with 695.4(B)(1). 695.4(B)(1) Overcurrent device selection. The overcurrent protective device shall be selected to carry indefinitely the sum of the locked-rotor current of the fire pump motor.
I feel the code is clear. If you choose to put a service ahead of the controller (which is not required or recommended) It shall comply with, but not limited to, articles 230.90 and 695.4.
As far as what "negative jurisdiction" asks for this, perhaps you should look yourself in the mirror and ask that question bitterman.

 

[marcb]

Wow what a bitterman. What does widely seperated mean Mr. Mcdowell