Fan Coil OCPD

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bcorbin

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I'm having an "uh-oh" moment. The situation is: 100 or so 120V fan coils within closets in a college dorm...each has its own hp-rated toggle disconnect, and integral thermal overload protection. There are 1/4, 1/5, and 1/8 hp units. I am giving each of them a dedicated circuit, protected by a 20A breaker. Does the overload protection matter or is this a violation of the 250% rule (permanent, automatically-started)? Do I need to go back and change all of those circuit breakers to 10 and 15 amps? If I'm doing it wrong, I'd rather not do it wrong 100 times. :confused:
 
bcorbin said:
I'm having an "uh-oh" moment. The situation is: 100 or so 120V fan coils within closets in a college dorm...each has its own hp-rated toggle disconnect, and integral thermal overload protection. There are 1/4, 1/5, and 1/8 hp units. I am giving each of them a dedicated circuit, protected by a 20A breaker. Does the overload protection matter or is this a violation of the 250% rule (permanent, automatically-started)? Do I need to go back and change all of those circuit breakers to 10 and 15 amps? If I'm doing it wrong, I'd rather not do it wrong 100 times. :confused:
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they have integral overload protection. no need to provide any additional overload protection.
 
petersonra said:
they have integral overload protection. no need to provide any additional overload protection.
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Yes...but does "overload" protection qualify as "short circuit" protection like a circuit breaker provides? To my understanding, a "heater" is a slow-blow thing...much slower than a circuit breaker, but then again, I haven't been at this game that long. Maybe I'm just being too cautious.
 
Do you happen to have the manufacturer and model of these units? Some of these manufacturer's clearly say that they want no more than a 15 amp branch circuit, and some even want smaller OCPD's. Since you're not permitted to have less than a 15 amp branch circuit, lower overcurrent protection for AHU's is normally provided by an SSU switched fuse cover in place of the toggle switch.
 
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mdshunk said:
Do you happen to have the manufacturer and model of these units?
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Yes, but apparently the NMC (National Mechanical Code :grin: ) has made the casual distribution of electrical information along with equipment a punishable offense. Like pulling teeth with those guys. I wonder when the last time my pump-and-fan-loving buddies had to visit Square D's or Hubbell's website was?
 
bcorbin said:
Yes, but apparently the NMC (National Mechanical Code :grin: ) has made the casual distribution of electrical information along with equipment a punishable offense. Like pulling teeth with those guys. I wonder when the last time my pump-and-fan-loving buddies had to visit Square D's or Hubbell's website was?
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Are you saying you couldn't find the manuals on the manufacturer's website?
 
mdshunk said:
Are you saying you couldn't find the manuals on the manufacturer's website?
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Oh, I found the manuals...they're on this page

http://www.commercial.carrier.com/commercial/hvac/product_technical_literature/1,3069,CLI1_DIV12_ETI4906_PRD71,00.html

so you can tell there is no shortage of information...just not the information I need. The ubiquitous "provide disconnecting means and overload protection as required." So I go back to my original stance, which is...I think I need to use a 10 or 15 amp breaker on these circuits to meet code. It's not a big deal, just that...I'll design a job for the model fan coil the ME gives me, then I'll have to go back double check the circuit breakers on the 100 fan coils which get supplied when he gets his mechanical shop drawings in. Gotta love designing it twice and getting paid once.
 
bcorbin said:
.I think I need to use a 10 or 15 amp breaker on these circuits to meet code.
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yeah, that's what I was trying to say earlier. Even though you can get a 10 amp breaker, I'm not sure there's any compliant way to use them at the head end of a branch circuit.
 
mdshunk said:
Even though you can get a 10 amp breaker, I'm not sure there's any compliant way to use them at the head end of a branch circuit.
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Yeah...that's funny, because several of these fan coils are 1/20 and 1/30 hp. I am damned sure that even a 10A circuit breaker would violate the 250% rule with those. Have a nice weekend! :D
 
bcorbin said:
Yeah...that's funny, because several of these fan coils are 1/20 and 1/30 hp. I am damned sure that even a 10A circuit breaker would violate the 250% rule with those. Have a nice weekend! :D
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Right. This is where the SSU comes into play.
 
We've installed quite a few of these things and typically they will state on the nameplate that the MOPD is 15 amps.
 
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