Jim W in Tampa
Senior Member
- Location
- Tampa Florida
Look at most # 6
Air handlers - once again
- Thread starter tonype
- Start date
- Status
Look at most # 6
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
So this animal has no heat or a/c that it will be moving around. With except. #2 I believe that if this unit moved a/c it would qualify also. I know I will get arguments on that.
Jim W in Tampa
Senior Member
- Location
- Tampa Florida
What code number do you wish to use ? Not this
422.12 Central Heating Equipment.
Central heating equipment other than fixed electric space-heating equipment shall be supplied by an individual branch circuit.
Exception No. 1: Auxiliary equipment, such as a pump, valve, humidifier, or electrostatic air cleaner directly associated with the heating equipment, shall be permitted to be connected to the same branch circuit.
Exception No. 2: Permanently connected air-conditioning equipment shall be permitted to be connected to the same branch circuit.
A/A Fuel GTX
Senior Member
- Location
- WI & AZ
- Occupation
- Electrician
Ok....so we know there is a boiler as part of this system, therefore, this AH has hot water coils running thru it making it part of a central heating system.
Jim W in Tampa
Senior Member
- Location
- Tampa Florida
He said plain vanilla ,to me that means radiators.
What i see out of the OP is he is looking at this already installed system to see if it complies with NEC and it does not. Are a few easy ways to fix.
1 they could change disconnect switch at each unit to a 15 amp breaker and then the #12 on the 20 is a feeded. Unless it is having problems that is cheap way out.
2 run new circuits to 4 of them. That likely will cost far more.
One thing that bothers me is the unit is rated at 15 amp max breaker to protect the fan motor and 24 volt xformer. Had this been a 10 kw heat strip they would say 60 amp breaker. Most units do not have any other protection inside ,so that now has the fan motor on a 60 but thats ok. Why ?
- Location
- Massachusetts
And plain pistachio means it's time for a new life jacket.
Jim, he is an HI trying to make a report.
Or they could simply leave it how it is.
I have no idea at all what you are talking about here.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I think Jim is saying that is this was a 10kw unit it would need a 60 amp breaker. When the a/c is on, the fan in the unit, which normally would require a 15 amp breaker, is now running on a 60 amp breaker.
A/A Fuel GTX
Senior Member
- Location
- WI & AZ
- Occupation
- Electrician
So why have air handlers:-?
- Location
- Massachusetts
Yes and he also said there is no protection for the motor and transformer which is untrue.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Factory assembly. Like the fan motor on an AC compressor, if the motor needs additional protection, it's up to the manufacturer to include it.
Jim W in Tampa
Senior Member
- Location
- Tampa Florida
OK what protection does it have ? Very few have an extra fuse. Are you saying a 60 amp breaker protects a 3 amp fan motor ?
Jim W in Tampa
Senior Member
- Location
- Tampa Florida
its part of a split unit for AC. Not always part of the heating system.
Jim W in Tampa
Senior Member
- Location
- Tampa Florida
"Or they could simply leave it how it is."
Yes they can if they don't care about being in violation of NEC.
Yes they can if they don't care about being in violation of NEC.
- Location
- Massachusetts
- Location
- Massachusetts
No I am saying the motor with have protection of some sort, impedance protected or internal thermal OL etc.
A class 2 transformer requires no protection.
Jim W in Tampa
Senior Member
- Location
- Tampa Florida
Bob, they use the same fan motor in the air handler with or without heat. Perhaps you do not do much air conditioner work other than hook them up. You order the heat strip seperate and install it in the unit. My point is if this unit has a fan that can be protected on a 60 amp breaker then it is protected at 20 amps too. They may have an internal overload but that will not care if the unit is breakered at 15, 20 or 60 amps. Not at all concerned about the treansformer as it will burn itself open in a split second at any amperage.
The NEC POLICE are on there way to your house. You just gave a written confeshion.
I do my own inspections at my house and never fail anything.LOL
A/A Fuel GTX
Senior Member
- Location
- WI & AZ
- Occupation
- Electrician
And that would exempt the AH from the requirements of 422.12? What if the split unit was a heat pump? I guess what I'm saying is that the term "Central Heating Equipment" IMO means air handlers regardless if there is heating or cooling going on.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
The fan unit, I am certain, has overload protection which will open the circuit on overload. If there is a ground fault or short circuit then I believe the 60 amp breaker will handle that. Is this any different then an a/c unit fused at 40 amps with #12 wire. There are even greater extremes where motors, in certain circumstances, can be protected at 1100%.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
I understand where Jim is coming from on why is 60 amp ok if heat is installed but has to be 15 if not.
I think that there is a problem with listing and or labeling. It is ok to have the 60 amp branch circuit protect the heater and blower. If no heater then minimum circuit ampacity is 15 amps. It could be down to 5 amps or less if we were not limited to 15 amp conductors by 310.5. And there is nothing prohibiting using a 5 amp overcurrent device but you must still use 15 amp conductors. They could possible mark nameplate to allow for 60 amp max overcurrent device with no heat but then they may need to require to raise the minimum circuit ampacity to do so even though the load is not there.
I think that there is a problem with listing and or labeling. It is ok to have the 60 amp branch circuit protect the heater and blower. If no heater then minimum circuit ampacity is 15 amps. It could be down to 5 amps or less if we were not limited to 15 amp conductors by 310.5. And there is nothing prohibiting using a 5 amp overcurrent device but you must still use 15 amp conductors. They could possible mark nameplate to allow for 60 amp max overcurrent device with no heat but then they may need to require to raise the minimum circuit ampacity to do so even though the load is not there.
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