rooftop HVAC recepts

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msteiner

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I have some 120V-20A rooftop fans to power, and I also need to provide convenience receptacles with 25' of these fans and other HVAC units on the roof (per 210.63). Does the Code allow me to tap off the line side of the fan disconnects, and run to a receptacle?
 
You are correct, Tervor, but I think you missed the "other HVAC units" part.

I might add, as long as it is a 15 or 20 amp branch circuit. If its higher than that, you will have to provide additinal OCP. (I'm not sure if you just meant a physical tap, or if you meant the NEC type of "tap" with a reduced conductor size).

Steve
 
steve66 said:
You are correct, Tervor, but I think you missed the "other HVAC units" part.

I might add, as long as it is a 15 or 20 amp branch circuit. If its higher than that, you will have to provide additinal OCP. (I'm not sure if you just meant a physical tap, or if you meant the NEC type of "tap" with a reduced conductor size).

Steve
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Actually I did see that Steve, I just wanted to point out that the 25' measurement does not need to include the rooftop fans only the HVAC equipment.

If this is a 120 volt, 20 amp circuit for a fixed piece of equipment can a receptacle be connected to the same circuit if the fan draws more than 10 amps?
 
I think your facetious question would be answered with a no. Also if this was done inside a disc., the line side lugs are only rated for one wire.I know were talking about a fan, but a lot of guy's try to do it off a hvac disc, and most of those branch circuits have a higher rated breaker for start up.
Rick
 
I've seen a number taken off the HVAC equipment- equipment that virtually never has a grounded conductor. They also usually took it off after the disconnect, also making it useless most of time it was required.

Receptacles can be added as an option to HVAC RTU's, and the manufacturer typically states the need for a neutral for those units.

A vacumn pump or refrigerant recovery machine, the main reason power is needed up there, can have 1/2 to 3/4 hp motors. Run a seperate cuircuit.
 
RUWired said:
I think your facetious question would be answered with a no. Also if this was done inside a disc., the line side lugs are only rated for one wire.I know were talking about a fan, but a lot of guy's try to do it off a hvac disc, and most of those branch circuits have a higher rated breaker for start up.
Rick
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The OP specifically asked if the rooftop receptacles could be tapped into the line side of a "120 volt 20 amp" rated circuit for an exhaust fan. I stand by my answer of yes. the answer would most definitely change if we were talking about a circuit that had no neutral conductor or was rated at more than 20 amps.
 
210.23(A)(2) Utilization Equipment Fastened in Place.
The total rating of utilization equipment fastened in place, other than luminaires (lighting fixtures), shall not exceed 50 percent of the branch-circuit ampere rating where lighting units, cord and- plug-connected utilization equipment not fastened in place, or both, are also supplied.
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Hmmm. I wonder if receptacles for tools used for service and repair (rarely used) qualify as the "cord-and-plug-connected utilization equipment not fastened in place" referred to above.

Would a drop light (in case of night repairs) qualify as the "lighting units" mentioned? Remember, we're talking rooftop receptacles here, not back-of-the-house grade-level ones.

When I read 210.23(A)(2), I envision household interior and/or exterior lighting and stationary appliances, not once-every-five-years occasionally-used equipment. Maybe it's just me.
 
I was thinking the roof fans were fixed in place. Maybe it's time for bed for me, 'cause I'm not even gonna look to see if I misread the OP. :D

Good night, Larry. :)
 
No, the point was, if I'm not mistaken, that the fan probably exceeds 50% of the circuit's capacity, meaning that lighting units and not-fastened-in-place equipment may not also be supplied by the same circuit.

Good night, George. Sleep tight.
 
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Boy we can confuse a simple question. :D

The OP did not ask if it was a good idea only if the code allows it.

Does the Code allow me to tap off the line side of the fan disconnects, and run to a receptacle?
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There is a simple answer....Yes.

Assuming all other code rules are followed.

Obviously you are not allowed to directly tap a 15 or 20 amp receptacle to a 30 amp circuit etc.

It is not unusual for large 480 volt three phase RTUs to be ordered with factory installed GFCI receptacles tapped off the line side of the factory installed unit disconnects.

These taps have there own disconect, OCP and supply a transformer to create 120 for the outlet.
 
LarryFine said:
No, the point was, if I'm not mistaken, that the fan probably exceeds 50% of the circuit's capacity, meaning that lighting units and not-fastened-in-place equipment may not also be supplied by the same circuit.
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Okay, we're on the same page. I just don't have any idea how big the fans are. I've never seen them.

iwire said:
Boy we can confuse a simple question.
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That is our specialty, what are you complaining about? :D
 
Right, but I believe that the occasional, temporary use of service receptacles may not fall under the intent of the rule.
 
georgestolz said:
A case could be made for that on a rooftop, but it'd be a hard sell at grade. :)
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Agreed, and addressed:
LarryFine said:
Remember, we're talking rooftop receptacles here, not back-of-the-house grade-level ones.
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Besides, I haven't seen very many grade-level roof-top exhaust fans.
 
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