where is the missing link between NFPA 70-08 and NFPA 20

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david

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NFPA 70-08 requires a service disconnect ( 230.90 Where Required.
Each ungrounded service conductor shall have overload protection. )

695.4(B)(1). Requires the overcurrent protection to be capable of caring lock rotor current.

I arrive on site there is an EATON 25 horse power 208 volt three phase fire pump controller being used as the service disconnect. The over current protection is being provided by an inverse time nonadjustable circuit breaker rated at 150 amps based on the provision found in NFPA 20 section 10.7.2.1 ( This equipment is listed as suitable for use as service equipment ) A rating falling between 150 and 250 percent of the motors full load amps.

Where do I find language in NFPA 70 that will accept this installation?

VII. Service Equipment ? Overcurrent Protection
230.90 Where Required.
Each ungrounded service conductor shall have overload protection.
Exception No. 4: Overload protection for fire pump supply conductors shall comply with 695.4(B)(1).

695.4 Continuity of Power. (B) Supervised Connection. A single disconnecting means and associated overcurrent protective device(s) shall be permitted to be installed between a remote power source and one of the following:
(1) Overcurrent Device Selection. The overcurrent protective device(s) shall be selected or set to carry indefinitely the sum of the locked-rotor current of the fire pump motor(s) and the pressure maintenance pump motor(s) and the full-load current of the associated fire pump accessory equipment when connected to this power supply.
 
I believe 695.4(B) refers to an additional disconnect that is not part of the fire pump controller. If you start reading at 695.4 I think you will see that.

It does not apply to a disconnect that is part of the fire pump controller.
 
I agree with that, however the way 230.90 is written there is no supporting language that says I can use a fire pump controller ( a service disconnect) with over current protection that uses a breaker rated at 150 amps . 230 states that overcurrent protection has to be provided and it will be based on lock rotor current 405 amps. Where is the language in NFPA 70 that will allow the fire pump controller with over current protection rated at 200% FLA to be used as the over current protection for the service entrance conductors? Shouldn’t there be an exception or some language that would allow a listed fire pump controller in lue of 695.4(B)(1). .
 
It looks to me like exception #1 for 230.90 refers to 430.52, which would allow the OCP at up to 250% of the motors full load current.

Steve
 
david said:
I agree with that, however the way 230.90 is written there is no supporting language that says I can use a fire pump controller ( a service disconnect) with over current protection that uses a breaker rated at 150 amps . 230 states that overcurrent protection has to be provided and it will be based on lock rotor current 405 amps. Where is the language in NFPA 70 that will allow the fire pump controller with over current protection rated at 200% FLA to be used as the over current protection for the service entrance conductors? Shouldn?t there be an exception or some language that would allow a listed fire pump controller in lue of 695.4(B)(1). .
Click to expand...
Where (or how) are you getting the 405A LRC? A 25HP motor would have a Code Letter of S to have that LRC... 16.0-17.99 ? 25HP = 400-449.75.

What are the size, type, wiring method, and conditions of installation for the service conductors to the controller?

Is the pump motor itself 25HP, or is that just the rating of the controller?

Can't say I entirely understand your question, so my questions are solely based on whether the installation is compliant with the NEC.
 
Smart $ said:
Where (or how) are you getting the 405A LRC? A 25HP motor would have a Code Letter of S to have that LRC... 16.0-17.99 ? 25HP = 400-449.75.

What are the size, type, wiring method, and conditions of installation for the service conductors to the controller?

Is the pump motor itself 25HP, or is that just the rating of the controller?

Can't say I entirely understand your question, so my questions are solely based on whether the installation is compliant with the NEC.
Click to expand...

Table 430.25(B) 25 HP Motor 208 volts 3PH Maximum lock rotor current in amps 404


The pump its self is 25 HP 208 Volt 3 Phase FLA 75

My question is this
(A) Mandatory Rules. Mandatory rules of this Code are those that identify actions that are specifically required or prohibited and are characterized by the use of the terms shall or shall not.

VI. Service Equipment ? Disconnecting Means
230.70 General.
Means shall be provided to disconnect all conductors in a building or other structure from the service-entrance conductors.

VII. Service Equipment ? Overcurrent Protection
230.90 Where Required.
Each ungrounded service conductor shall have overload protection.
Exception No. 4: Overload protection for fire pump supply conductors shall comply with 695.4(B)(1).

695.4(B) (1)
(1) Overcurrent Device Selection. The overcurrent protective device(s) shall be selected or set to carry indefinitely the sum of the locked-rotor current of the fire pump motor(s) and the pressure maintenance pump motor(s) and the full-load current of the associated fire pump accessory equipment when connected to this power supply. The next standard overcurrent device shall be used in accordance with 240.6. The requirement to carry the locked-rotor currents indefinitely shall not apply to conductors or devices other than overcurrent devices in the fire pump motor circuit(s).

I am required to have overcurrent protection for a fore pump service equipment rated to allow lock rotor current indefinitely.

When the installer is using the fire pump controller as the service disconnect in accordance with NFPA 20 a listed 25 HP controller that uses ( a service disconnect) with over current protection rated at 150 amps .

Where is the language in NFPA 70 that will allow the fire pump controller with over current protection rated at 200% FLA to be used as the over current protection for the service entrance conductors? Shouldn?t there be an exception or some language that would allow a listed fire pump controller in lue of 695.4(B)(1). .
 
After a little review of NFPA20, I better understand your question. I too cannot find an NEC equivalent to NFPA20 10.7.2.1.
 
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