In the '99 cycle, Article 695: Fire Pumps, a voltage drop requirement was added to 695.7. Luck would have it that I have a '96 and '02 Handbook but not '99. If anyone of you have a '99 Handbook, can you look that up to see if they commented on this and why? I presume to protect the conductors from flaming out in the event of a lock rotor state.
Speaking of Handbooks. I am very intersted in located older NEC Handbooks and code books. I am not sure when the NFPA started to publish the Handbooks, I prefer the ones published by them.
The NFPA/NEC Handbooks I am currently looking for are: 1999 1990 1984 1978 and older
If I can not locate the Handbooks, I would probably settle for just the codebooks although I do have the 1990 and 1999.
If you have any you are willing to let go of, lets talk
I suspect it is because the fire pump rules allow overcurrent protection to handle LRA but if you have too much voltage drop you still might not get enough power to the pump to grind up that carp it sucked up and send it on down the line.
Under 650-7 of the 1999 handbook it reads" Voltage Drop" The voltage at the controller line terminals shall not drop more than 15 percent below normal (controller-rated voltage)under motor starting conditions. The voltage at the motor terminals shall not drop more than 5 percent below the voltage rating of the motor when the motor is operating at 115 percent of the full-load current rating of the motor.
Exception: This limitation shall not apply for emergency run mechanical starting.
There is no "Blue" highlighted wording in the handbook after this section.
I have the ROP and it has several pages of stuff. It looks like they rewrote the whole article. I was really looking for the substantiation of the Voltage Drop thing but no joy so far. I didn't really read the whole thing.
Greg was on the right track. The changes to Article 695 was to put it in line with NFPA 20: Standard for the Installation of Stationary Pumps for Fire Protection. If you would dig into the1999 NFPA 20 and it's ROP, you would find the voltage drop requirement is to prefer the pump relay from dropping out and causing "relay chatter". That would be rather narwlly sounding on a big pump not to mentioned the lost of the pump in an emergency