Working Space around AC units

[Bruce Ramsey]

I inspected a home yesterday that had two exterior air conditioning units installed 12 inches apart. I called the manufacturer and they indicated that they require a min. 24 inches seperation between mulitple units to allow for proper air flow. American Standard model # 2A7B3030A1000AA

But they also indicated that NEC requires 36 inches of working room in front of the electrical connections. They said that depending on the orientation of the units, if the electrical connections were facing the other unit, NEC would require 36 inches seperation between the units.

Either way, my particular installation was wrong. I know there is a required working space of 30x36 in front of service panels but I had not heard about electrical connections to A/C coils. The manufacturer may have been interperting the clearance in front of the disconnect panel code reference to apply to the electrical connection to the unit itself.

Can you provide any NEC or IRC references that might support the idea that there must be 36 inches of working space in front of the exterior A/C coils?

The manufacter mentioned they accept 12 clearance to the building assuming the unit is oriented to provide 36 working space to the electrical connections. I certainly would like to have 36 clearance on the line set and electrical connection point since the data plate is most often in this location. It would make servicing and inspecting way easier.

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[Jerry Peck - Codeman]

Hi Bruce,

Actually, it looks like you've got several things wrong going on there.

Question for you: are those a/c condenser units out beyond the outer edge of that bay window? If not, there is also the issue with clearances, typically a/c manufacturers require at minimum of 48 inches to 60 inches clear height above the top of the discharge.

I've been waiting on replying hoping to get a reply back from the manufacturer with the installation instructions.

I could address some of it now, but will wait and do a complete reply when I receive those installation instructions, hoping for later today, if not then tomorrow.

Or would you like the IRC and NEC references and then the manufacturer's installation instruction information later when it comes in?

Let me know if you would like a partial answer based on the codes while I am waiting on the installation instructions.

[Jerry Peck - Codeman]

Hi Bruce,

While I am waiting on the installation instructions from the manufacturer to answer some other things about that installation, I will answer your question:

Can you provide any NEC or IRC references that might support the idea that there must be 36 inches of working space in front of the exterior A/C coils?

The IRC has two different working space requirements, one for the mechanical aspect (30 inches by 30 inches) and one for the electrical aspect (30 inches by 36 inches), with the electrical aspect being the same as in the NEC (30 inches by 36 inches).

From the 2006 IRC. (underlining and bold are mine)
- From the Mechanical chapter:
- - M1305.1 Appliance access for inspection service, repair and replacement. Appliances shall be accessible for inspection, service, repair and replacement without removing permanent construction, other appliances, or any other piping or ducts not connected to the appliance being inspected, serviced, repaired or replaced. A level working space at least 30 inches deep and 30 inches wide (762 mm by 762 mm) shall be provided in front of the control side to service an appliance. Installation of room heaters shall be permitted with at least an 18-inch (457 mm) working space. A platform shall not be required for room heaters.

- From the Electrical chapter:
- - E3305.2 Working clearances for energized equipment and panelboards. Except as otherwise specified in Chapters 33 through 42, the dimension of the working space in the direction of access to panelboards and live parts likely to require examination, adjustment, servicing or maintenance while energized shall be not less than 36 inches (914 mm) in depth. Distances shall be measured from the energized parts where such parts are exposed or from the enclosure front or opening where such parts are enclosed. In addition to the 36-inch dimension (914 mm), the work space shall not be less than 30 inches (762 mm) wide in front of the electrical equipment and not less than the width of such equipment. The work space shall be clear and shall extend from the floor or platform to a height of 6.5 feet (1981 mm). In all cases, the work space shall allow at least a 90-degree opening of equipment doors or hinged panels. Equipment associated with the electrical installation located above or below the electrical equipment shall be permitted to extend not more than 6 inches (152 mm) beyond the front of the electrical equipment.

From the 2008 NEC.
- 110.26 Spaces About Electrical Equipment.
- - Sufficient access and working space shall be provided and maintained about all electrical equipment to permit ready and safe operation and maintenance of such equipment.
- - - (A) Working Space. Working space for equipment operating at 600 volts, nominal, or less to ground and likely to require examination, adjustment, servicing, or maintenance while energized shall comply with the dimensions of 110.26(A)(1), (A)(2), and (A)(3) or as required or permitted elsewhere in this Code.
- - - - All of the requirements are rather long to copy and paste here, however, the minimum required width in 110.26(A) is 30 inches and the minimum required depth in front of the electrical equipment (the air conditioning condenser unit is "electrical equipment") is 36 inches, and the space in front of the electrical service access to the air conditioning condenser unit falls within that minimum 36 inches depth in front of the electrical equipment access area.

I can post the entire NEC 110.26(A) if you would like, but referring to 110.26(A) should be sufficient as they need to read the applicable sections in 110.26(A) themselves.

110.26(A)(1) and Table 110.26(A)(1) addresses the minimum depth of the working space as being 36 inches.
110.26(A)(2) addresses the minimum width of the working space as being 30 inches.

[Bruce Ramsey]

Jerry,

Thank you for the references. I posted Friday morning and headed out of town for the weekend.

Yes, the units are poorly located for several reasons. I initally was thinking about the spacing between the units when I called the manufacturer. The tech person stalled and gave me the answer 12 inches from the building was what they wanted while he looked up the specific model. Then he said it had to have 36 inches because of NEC. Eventually he said they wanted 24 inches between units for air flow.

He seemed very proud of the NEC reference of 36 inches. I was just a little leary of the answer so wanted to check another source.

Yes, the units are just a bit under the bumpout. The report will mention the vertical access, the spaceing between the units and NEC 36 inch clearance issue. Get mechanical contractor to do it right.

Thank for your response

[Jerry Peck - Codeman]

Hi Bruce,

The tech person stalled and gave me the answer 12 inches from the building was what they wanted while he looked up the specific model. Then he said it had to have 36 inches because of NEC. Eventually he said they wanted 24 inches between units for air flow.

The 12 inches he said is the most common clearance requirement to allow for proper air flow, thus, two units side-by-side competing for the same air need twice that, or 24 inches, which is where that comes from.

There are some manufacturers who allow different clearances on various sides, sometimes even like 12 inches on two side, 6 inches on the third side, then the fourth side is not mentioned, however, the fourth side is the mechanical and electrical access side so that gets 36 inches. I've even seen some which stated 12 inches per side and 24 inches between adjacent units, except that only one side of adjacent units may be reduced below 12 inches, which means that when there are three adjacent units only one center space is allowed to be reduced, say between unit 1 and unit 2, with the space between unit 2 and unit 3 being required to be the full 24 inches.

Hopefully I will get the installation instructions tomorrow and have that answer also.

[Bruce Ramsey]

"the working space in the direction of access to panelboards and live parts likely to require examination, adjustment, servicing or maintenance while energized shall be not less than 36 inches (914 mm) in depth. Distances shall be measured from the energized parts where such parts are exposed or from the enclosure front or opening where such parts are enclosed. In addition to the 36-inch dimension (914 mm), the work space shall not be less than 30 inches (762 mm) wide in front of the electrical equipment and not less than the width of such equipment."

The electrical reference states while energized. I can understand this would be true for panelboards but when servicing AC units, they should be de-engerized and thereby potentially negating this requirement.

The mechanical reference combined with the manufacturers requirements is enough documentation to support my position that this particular installaion is flawed.

Thank you.

[Jerry Peck - Codeman]

Bruce,

The electrical reference states while energized. I can understand this would be true for panelboards but when servicing AC units, they should be de-energized and thereby potentially negating this requirement.

Actually, that is quite incorrect.

Service is frequently done with the a/c condenser units energized so the technician can measure voltages, make sure contactors are working, etc., all done "while energized".

The mechanical reference combined with the manufacturers requirements is enough documentation to support my position that this particular installation is flawed.

The only difference between the electrical clearances (36 inches) and mechanical clearances (30 inches) is the additional 6 inches of clearance to give the person room to jump back and put the equipment out of their reach, disengaging their contact with the energized equipment.

Additionally,

"the working space in the direction of access to panelboards and live parts likely to require examination, adjustment, servicing or maintenance while energized "

, are *you* not doing an "examination" on the equipment "while energized"? Yes you are.

[Jerry Peck - Codeman]

Hi Bruce,

Here are the installation instructions.

Note: Place cursor over link, right click, left click 'Open in New Window'.

http://www.eastwestdata.com/eastwestdat ... lGuide.pdf

[Bruce Ramsey]

Jerry,

Thank you for the installation manuel (spanish version). Just sent it off to the client.

The arguement I can see arising is commonly the line set and electrical are installed on the corner of the unit so is neither on one side or the other. Or alternately is on both sides at the same time. Therefore the unit must be at least 30-36 inches away from the structure to allow for servicing regardless of the minimun clearance around the unit set by the manufacturer for airflow. Based on that, almost every installation is wrong.

This is going to make a lot of HVAC installers uphappy. I know, not my concern. They should be doing their job correctly to begin with. I think this I will send this along to the members of the local HI association as a tip to be on the lookout for. Maybe if we all make a stink, the HVAC installers will begin to change.

Thanks for the research.

[Jerry Peck - Codeman]

Hi Bruce,

Thank you for the installation manuel (spanish version).

Not quite sure what you mean there as the one posted is is the English version, so I am missing something, maybe a play on words going whoosh right over my head?

The arguement I can see arising is commonly the line set and electrical are installed on the corner of the unit so is neither on one side or the other. Or alternately is on both sides at the same time. Therefore the unit must be at least 30-36 inches away from the structure to allow for servicing regardless of the minimun clearance around the unit set by the manufacturer for airflow. Based on that, almost every installation is wrong.

That argument is set aside on page 7 of the manual (English version?) as when you look at the top drawing, plan view, it shows the slightly off center fan and the "Service Panel" located on the 'far' side, the wise off center side.

This is going to make a lot of HVAC installers uphappy.

Just clarifying what "This is" is? If you are referring to the electrical service on two sides, that really is specified as being on the 'far' off center side, as stated above.

One of the big things I always found, after having HVAC installers address clearances for air flow and clearances for service, 36 inches instead of 30 inches (and it is nice to see that the installation instructions recognize that difference and refer to the NEC), was the requirement for the unit *to not be under the roof run off*. Placing those units 12 inches from the wall placed the units dead-center under the drip edge of a standard 24 inches overhang. Either move the unit farther from the wall or install a gutter above the unit. Eventually it started to become common for builders to install a 10 foot long piece of gutter above the a/c condenser units to solve that before it was written up. Another option would have been to have moved the units out 36 inches from the house wall to allow for both clearance from roof runoff and to allow for the required 36 inch working space on that side

I think this I will send this along to the members of the local HI association as a tip to be on the lookout for. Maybe if we all make a stink, the HVAC installers will begin to change.

That is how change is done, and how we did it in South Florida before some of us old times retired and moved away.

While you are passing along the information to those Home Inspector association members, if you would pass along this web site for answering their questions, I would greatly appreciate you doing that, thank you.