Number of duplex recepticals?

[charlie b]

Charlie, we do not have to cite article 220 because article 210 does this for us in 210-11 which tells us branch circuits for lighting and appliances? SHALL be provided to supply the loads computed in accordance with 220-10

I have to install branch circuits to supply that load, but nothing tells me how to design those branch circuits. 220-10 gives me a list of things that must get power. But it doesn?t tell me how to do it.

How would 210-20(A) apply for non-dwelling receptacles in your opinion?

A receptacle is never a continuous load. Nor for that matter is it a non-continuous load. Indeed, a receptacle is not a load at all. The load is whatever is plugged in, and that happens after we leave. But as for any question of continuousness, when we install a receptacle, we do not have to take into account the possibility that the owner may choose to plug in a floor lamp and keep it turned on all night.

 

[SmithBuilt]

No limit IMO.

I believe the answer is in the title and the wording of art. 220.

The article does not state Calculating Branch Circuit Size or load allowed. It states Branch Circuit Load Calculations (220 Part II). Then goes on to discuss the loads that are served by branch circuits.

It states receptacle outlets shall be calculated at not less than 180 va for each strap. This is just for sizing the service, IMO.

If I needed to size a branch circuit this is not where I would look.
I would go to Art.210.23. Which does not say anything about the 180 va calculation.

Tim

 

[roger]

Tim, then why is the title "ARTICLE 220 Branch-Circuit, Feeder, and Service Calculations" for it to be as you say it would have to be called "ARTICLE 220 Branch-Circuit and Feeder Calculations for sizing Services".

Roger

 

[SmithBuilt]

Isn't that ultimately what the article is about?

Why didn't Art 210.23(A) state your are only allowed 10 or 13 receptacles per branch. It limits you in other ways why not receptacles?

I believe its because if a designer knows what will be used in a commercial building he can put as many convenience outlets in as he would like.




I don't mean to keep debating this, its just that I learn something every time.
I have never violated this rule and probably will not.

 

[M. D.]

It is to be used to calculate load, so as to make sure that the service has enough capacity, and that the feeder to any panel has enough capacity. It is not to be used to design branch circuits, as the NEC does not tell us how to design anything.

It is telling us what the load is for calculating purposes , including the branch circuit .

 

[Chris6245]

I have 6 sets of plans that show up to 30 duplex receptacles on a circuit. They are engineered stamped drawings and have NEVER been questioned during plan review. I have never failed because of this because they are on the approved drawings. The subject has been brought up by a few inspectors but when they call the plans examiner they are told it is fine because they are engineered drawings. This happens to be a furnature store and the recepts are used for display lamps that will only carry a 15watt lamp. It's on the drawings, they have cases of 15watt lamps and that's all they use.
I was told that 220 was to be used only IF the load being served was unknown. Am I right? am I wrong? Who knows. But I have yet to fail because of it.

 

[roger]

But I have yet to fail because of it.

Chris, many jobs have code violations slip by inspectors, and it will continue to happen.

Not being failed for an infraction does not validate it.

Is this really an issue for receptacles that will rarely be used, not IMO, but MO is not an NEC exception. :smile:

Roger

 

[Chris6245]

I have 6 sets of plans that show up to 30 duplex receptacles on a circuit. They are engineered stamped drawings and have NEVER been questioned during plan review. I have never failed because of this because they are on the approved drawings. The subject has been brought up by a few inspectors but when they call the plans examiner they are told it is fine because they are engineered drawings. This happens to be a furnature store and the recepts are used for display lamps that will only carry a 15watt lamp. It's on the drawings, they have cases of 15watt lamps and that's all they use.
I was told that 220 was to be used only IF the load being served was unknown. Am I right? am I wrong? Who knows. But I have yet to fail because of it.

It doesn't "slip by"

 

[roger]

It doesn't "slip by"

Then the plans examiners are in effect executing 90.4 in a proper interpretation of the rule, (not that engineered drawings take precedence over the NEC) and I admire them for using 90.4 correctly, that doesn't change the fact that 220 has five individual sections dealing with individual subjects.

Roger

 

[Chris6245]

OK...Let me ask this, 220.43 tells you how to calculate track lighting but the comentary in the UNenforcable handbook tells you that it is ONLY for load calculations and you may install as many feet per circuit, but you can only load that track to the size of the circuit supplying it (not quoted) but the jist of it. So why would it matter how many receptacles are on a circuit if it can only supply the load of the circuit supplying it anyway? Seems the same to me...you can't put a 30amp load on a 15 or 20amp circuit...well you could for a short time...Just the same as I could plug 2 18amp saws into 1 20amp receptacle...sure I could do it but it won't work for long. That's why I feel this is for calculations only if the load being served is unknown. JMO

 

[roger]

OK...Let me ask this, 220.43 tells you how to calculate track lighting but the comentary in the UNenforcable handbook tells you that it is ONLY for load calculations

220.43 is in part III "Feeder and Service Load Calculations" it is outside of part II "Branch Circuit Load Calculations"

In other words 220.43 has nothing to do with a Branch Circuit Calculation.

Roger

 

[Chris6245]

220.43 is in part III "Feeder and Service Load Calculations" it is outside of part II "Branch Circuit Load Calculations"

In other words 220.43 has nothing to do with a Branch Circuit Calculation.

Roger

Got me there....OK..next question or maybe statement.Lets go back to 220.14(I) I guess it doesn't really limit the # of receptacles on a circuit, it only limits the "outlets" or "yokes" so in reality you could have anywhere from 13 recets to 39 recepts on a circuit as long as you don't exceed 13 yokes no matter if you have single recepts, duplex recepts or if you can find them tripple recepts....It only uses "yokes" or "Outlets" for load calcs...doesn't make sense...13 to 39 is a big differance...why would 39 single recepts be any different than 13 tripple recepts? Says calculations only to me and not a limit on recepts...?????

 

[tryinghard]

Three things are for sure: Article 220 is used for calculating, Article 210 is used for branch circuits, and every electrician knows a receptacle not in used has no load!

So if I want to confirm branch circuitry installation I?ll go to 210 and low-&-behold 210-11 tells me ?Branch circuits for lighting?shall be provided to supply the loads CALCULATED in accordance with 220-10?!

Notice the tie, Article 210 is telling me to use Article 220 for this information!

Again 210-11(A) ?The minimum number of branch circuits shall be determined from the total CALCULATED load? And again cites the use of Article 220 for this information.

I wonder; if you did a design-build would you install all the general use receptacles on one circuit without prequalification from your client? Or if you noticed all the receptacles on one circuit on your construction drawings would you just install them without questioning? The fact is the status quo has always been 180VA per receptacle in non-dwelling applications.

 

[tryinghard]

Oxymoron

Oxymoron

No limit IMO.

I believe the answer is in the title and the wording of art. 220....

It states receptacle outlets shall be calculated at not less than 180 va for each strap. This is just for sizing the service, IMO.

It is contradictory to say there is no limit for quantity of receptacles in commercial (non-dwelling) applications if you?re confirming this thought with Article 220. Article 220 tells us to use 180VA per receptacle to size feeders and services but not branch circuitry? Why would we not want to use the 180VA to size the branch circuit capacity as well?

In any case the 180VA is a projection ? not design - of likely load and it follows a minimum good practice of installing.

 

[charlie b]

Notice the tie, Article 210 is telling me to use Article 220 for this information!

No it is not. It is pointing you to 220 as the place to find a list of the loads that require power. It is not telling you to use the calculation as a basis for designing branch circuits. The NEC is not a design manual; it does not tell us how to design anything.

Again 210-11(A) ?The minimum number of branch circuits shall be determined from the total CALCULATED load? And again cites the use of Article 220 for this information.

That only tells us how many branch circuits are needed, as a minimum. I can install more, if I like. But it does not tell us how to split the load among the branch circuits.

The fact is the status quo has always been 180VA per receptacle in non-dwelling applications.

With respect, I do not accept any person?s assertion that something is ?fact,? without documented evidence that it is indeed ?fact.? You have expressed your considered opinion, and it may well be based on experiences above and beyond my own. But fact is fact, and opinion is not fact.

 

[SmithBuilt]

Article 220 tells us to use 180VA per receptacle to size feeders and services but not branch circuitry?

I do not believe it is referring to the design of one actual branch circuit. Just a means of calculating loads that are on all branch circuits. In order to design a service you do not calculate the actual load on each branch then sum up the total of each branch circuit, you calc all the loads.

Why would we not want to use the 180VA to size the branch circuit capacity as well?

We might and sometimes do. But there could be that occasion where someone just needs a bunch of receptacles for convenience.

In any case the 180VA is a projection – not design - of likely load and it follows a minimum good practice of installing.

It may not even be a good minimum for today. Offices have too many computers, printers, etc to follow the minimum.

edit I see Charlie types faster than I.

 

[M. D.]

Fact is fact ,... It is a fact that this is what is being taught .
,..until the Supreme Court renders an opinion that is :smile:

[FONT=Arial, Helvetica, sans-serif]

[FONT=Arial, Helvetica, sans-serif]By Mike Holt, for EC&M Magazine[/FONT]
[FONT=Arial, Helvetica, sans-serif]Q1 What is the maximum number of 15 or 20A, 125V receptacle outlets permitted on a 20A, 120V general-purpose branch circuit in a commercial occupancy?[/FONT]
[FONT=Arial, Helvetica, sans-serif]A1 For commercial occupancies, the NEC requires each receptacle outlet to be calculated at 180 VA [220.14(I)]. Therefore, the maximum number on a 20A circuit would be 13. [/FONT]

[FONT=Arial, Helvetica, sans-serif]Circuit VA = Volts x Amperes
Circuit VA = 120V x 20A
Circuit VA = 2,400 VA
Number of Receptacles = 2,400 VA/180 VA
Number of Receptacles = 13[/FONT]
​

[/FONT]

 

[roger]

Fact is fact ,... It is a fact that this is what is being taught .
,..until the Supreme Court renders an opinion that is :smile:

This is also taught by Tom Henry, James Stallcup, Charles Miller, and most likely every other instructor in the nation. :smile:

Roger

 

[George Stolz]

It is not telling you to use the calculation as a basis for designing branch circuits. The NEC is not a design manual; it does not tell us how to design anything.

The first time, I bit my tongue. This time, I'm going to remind you of 210.23, 210.52, and 210.70, just off the top of my head - how are these not design mandates?

Why is the direction to use 220 any different?

 

[tryinghard]

It is not telling you to use the calculation as a basis for designing branch circuits. The NEC is not a design manual; it does not tell us how to design anything.

Why do you think designing is used for this required calculation?

With respect, I do not accept any person?s assertion that something is ?fact,? without documented evidence that it is indeed ?fact.? You have expressed your considered opinion, and it may well be based on experiences above and beyond my own. But fact is fact, and opinion is not fact.

Charlie with reciprocating respect I believe the burden of proof is on your side. I may have used the word ?fact? hastily but not status quo which can be described as: the present state of belief or policy, and just like the pole reveals above the majority accepts the 180 VA per receptacle as the rule.