motor protection overkill?

[quinn77]

Recently I was called to a kitchen for fan motors "on fire". When I showed up the fire prot. contractor had already been there to shut them down. The tech. removed on of the motors from the wall mounted exaust hoods outside. He told the owners to call a cert. electrician. The windings had totally melted down, so I investigatd. A 3 ph 208v mbc feeds two 3ph 1HP fan motors with NO THERMAL OVERLOAD protection, just protection for conductors. So I installed 1 40 amp IEC contactor w/ therm. overl. relay at 3.3 FLA in sealed fiberglass enclosures next to the fans. The original electrician( on vacation when problem occured ) recently returned and told owner ( friend of his) that I had sold him something he didn't need. I told him that the N.E.C. required this as with the manufacturer also had instructions on the shroud which read "ELECTRICIAN, IF THREE PHASE, REMOTE SUPPLEMENTAL PROTECTION MUST BE INSTALLED."
Did I overkill this install? Or was my interpretation of the NEC correct?

 

[ceb58]

Recently I was called to a kitchen for fan motors "on fire". When I showed up the fire prot. contractor had already been there to shut them down. The tech. removed on of the motors from the wall mounted exaust hoods outside. He told the owners to call a cert. electrician. The windings had totally melted down, so I investigatd. A 3 ph 208v mbc feeds two 3ph 1HP fan motors with NO THERMAL OVERLOAD protection, just protection for conductors. So I installed 1 40 amp IEC contactor w/ therm. overl. relay at 3.3 FLA in sealed fiberglass enclosures next to the fans. The original electrician( on vacation when problem occured ) recently returned and told owner ( friend of his) that I had sold him something he didn't need. I told him that the N.E.C. required this as with the manufacturer also had instructions on the shroud which read "ELECTRICIAN, IF THREE PHASE, REMOTE SUPPLEMENTAL PROTECTION MUST BE INSTALLED."
Did I overkill this install? Or was my interpretation of the NEC correct?

I think you did as you should have. Take a look at 430.32 D 1 which takes you back to 430.32 B 1 Along with that you followed 100.3 B. With all that said the fact the motor had a thermal melt down should tell you the original EC did not do what should have been done.

 

[puggy17]

in addition to the code 430.32 (B) (1-4), remind the customer that the code is a minimum standard. The manufacturer will give additional specs for their equipment to remain under warranty and within their limits. You did exactly what is expected to "protect persons and property."