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Number of 120v receptacles on a circuit

jar546

jar546

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For other than dwelling units, how do you interpret the code for the maximum amount of receptacles on a 120v circuit in commercial applications?

Do you figure per duplex or per receptacle on the duplex?

I am talking about general use receptacles such as in an office with an unknown, undeclared use.
 
Here is a good graphic

002ecmCBfig2.jpg
 
Now that is clarified (unless someone disagrees), how many general use duplex receptacles can you place on a single 120v 20A circuit?

I personally have used 13 as my cut off in commercial applications for general use with no declared specific load.
 
jar546 said:
Now that is clarified (unless someone disagrees), how many general use duplex receptacles can you place on a single 120v 20A circuit?I personally have used 13 as my cut off in commercial applications for general use with no declared specific load.
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I would agree.

IF you take 20 amps multiply that by 120 volts you get 2400 voltamperes. You then divide 2400 VA by 180 VA you get 13.33333333. So if you install 13 duplex receptacles on a 20 amp circuit you would comply with the 180 VA rule in 220.14.

Now it can be argued that the rules in Article 220 are for calculations only and do not govern how many receptacles you install on a circuit.

Chris
 
raider1 said:
I would agree.IF you take 20 amps multiply that by 120 volts you get 2400 voltamperes. You then divide 2400 VA by 180 VA you get 13.33333333. So if you install 13 duplex receptacles on a 20 amp circuit you would comply with the 180 VA rule in 220.14.

Now it can be argued that the rules in Article 220 are for calculations only and do not govern how many receptacles you install on a circuit.

Chris
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I have heard that argument but don't buy it. What about Range calculations? I have heard the same argument about T. 220.55, however Note #4 Talks of branch circuit loads.
 
Greetings,

180 VA per outlet are for load analysis purposes, not for determining the # of outlets on a circuit. That said, it is ok to calculate that way for the number of outlets on a circuit and a lot of folks do.

BSSTG
 
BSSTG said:
Greetings,180 VA per outlet are for load analysis purposes, not for determining the # of outlets on a circuit. That said, it is ok to calculate that way for the number of outlets on a circuit and a lot of folks do.

BSSTG
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So are you saying that calculations cannot be used to limit the number of 120v receptacles on a circuit in other than dwelling units?

Please clarify.

How is it possible to install 20 duplex receptacles (each rated for 20A) where as the calculated load is 30A?
 
jar546 said:
So are you saying that calculations cannot be used to limit the number of 120v receptacles on a circuit in other than dwelling units?Please clarify.

How is it possible to install 20 duplex receptacles (each rated for 20A) where as the calculated load is 30A?[/quote

220.14 (I)

(I) Receptacle Outlets. Except as covered in 220.14(J) and (K), receptacle outlets shall be calculated at not less than 180 volt-amperes for each single or for each multiple receptacle on one yoke. A single piece of equipment consisting of a multiple receptacle comprised of four or more receptacles shall be calculated at not less than 90 volt-amperes per receptacle. This provision shall not be applicable to the receptacle outlets specified in 210.11©(1) and ©(2).

(K) Banks and Office Buildings. In banks or office buildings, the receptacle loads shall be calculated to be the larger of (1) or (2):

(1) The calculated load from 220.14(I)

(2) 11 volt-amperes/m2 or 1 volt-ampere/ft2

(L) Other Outlets. Other outlets not covered in 220.14(A) through (K) shall be calculated based on 180 volt-amperes per outlet.
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Greetings JAR

Well I'm not known for going for "handbooks" since they are not Code. However, I did in this case. Perhaps my memory is fading. Heck I know it is. However, I recall this discussion in my Master Code studies in college 30 years ago and the consensus we had was that the outlet calcs. were strictly for load figures. Bear in mind we never looked in a handbook back then as they are not code and were worthless for master exam prep to a great extent. Also back then master electrician exams were done by municipalities in Tx and some were so hard they were rarely passed. We were studying for specific tests where you had to know what the proctor wanted. Houston's test was an 8 hour test. It was tough. Of all of the hundreds of questions I encountered not one time was there ever a question on how many outlets on a circuit and maybe that's why as it was maybe controversial. Now the handbook indicates otherwise and the # of outlets on a circuit is determined by your method so I suppose I'm wrong. Happens some time. Maybe the thinking has changed over the years some too. Don't know.

Part of me still says it makes no sense. I look at my office area and adjoining offices and see less load on the total of all outlets than you will see at my house. And the Code does not specify how many outlets on a circuit there with all of the gizmos plugged in, electronics and such.

Have A Blessed Day!

BS
 
Even though you don't have much plugged in now, you may have people moving in-out with different loads, new (higher amp) equipment moving in out... So the commercial receptacles are limited for that reason. (IMO)

The commentaries in the handbook are not enforceable, I agree. However, the commentaries are from individuals that have been in the field maybe longer than you and I have and are experts. So, I would say the commentaries are NOT jibberish. again IMO.
 
edo said:
Even though you don't have much plugged in now, you may have people moving in-out with different loads, new (higher amp) equipment moving in out... So the commercial receptacles are limited for that reason. (IMO)The commentaries in the handbook are not enforceable, I agree. However, the commentaries are from individuals that have been in the field maybe longer than you and I have and are experts. So, I would say the commentaries are NOT jibberish. again IMO.
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Commentaries in code hand books are not enforceable is a true statement, but they are culmination of statement from substantiations taken from SME directly involved with Code Making Panels, and staff members of various code groups.
 
gfretwell said:
One yoke?View attachment 1791
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One piece of equipment with one yoke = 360 va

(I) Receptacle Outlets. Except as covered in 220.14(J) and (K), receptacle outlets shall be calculated at not less than 180 volt-amperes for each single or for each multiple receptacle on one yoke. A single piece of equipment consisting of a multiple receptacle comprised of four or more receptacles shall be calculated at not less than 90 volt-amperes per receptacle. This provision shall not be applicable to the receptacle outlets specified in 210.11©(1) and ©(2).
 
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since there are virtually no required receptacles in commercial construction, how can you overload a circuit?
 
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