Duplex outlet GFI question

[Mark Patterson]

Is there a limited number of 20 amp duplex outlets and I can put on a 20 amp duplex GFI outlet load side? I am trying to put as many as I can because I am only pulling 27.8 watts on each duplex outlet down from the GFI 20 amp outlet.

 

[Dennis Alwon]

Is there a limited number of 20 amp duplex outlets and I can put on a 20 amp duplex GFI outlet load side? I am trying to put as many as I can because I am only pulling 27.8 watts on each duplex outlet down from the GFI 20 amp outlet.

There is no limit in residential but you would be limited in a non dwelling setting by the 180va / receptacle. The GFCI doesn't care.:grin:

 

[Mark Patterson]

There is no limit in residential but you would be limited in a non dwelling setting by the 180va / receptacle. The GFCI doesn't care.:grin:

Dennis Just to make sure I understand what you are saying in your reply. I need to figure 180 watts per 20 amp duplex outlet in a commerial setting. Is this what you are telling me when you say 180va/receptacle.

 

[Dennis Alwon]

Dennis Just to make sure I understand what you are saying in your reply. I need to figure 180 watts per 20 amp duplex outlet in a commerial setting. Is this what you are telling me when you say 180va/receptacle.

Yes.........

 

[Dennis Alwon]

Sorry I should have posted the article 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(C)(1) and (C)(2)

So for a 20 amp circuit you are limited to 13 receptacles.
20 amps * 120= 2400
2400/180= 13.33

 

[charlie b]

Sorry, Dennis, but I disagree, from two perspectives. First and foremost, the manufacturer of the GFCI device might have published a limit on the downstream load. If so, then that would govern the installation.

Secondly, and this has been debated on this forum, at length, more than once already, but I continue to assert that there is no limit to the number of receptacles you can put on a 20 amp circuit, regardless of whether you are talking commercial or residential. My basis is that nothing in 210 calls upon you to invoke the load calculations within 220, in the design of your branch circuits.

 

[jumper]

Sorry, Dennis, but I disagree, from two perspectives. First and foremost, the manufacturer of the GFCI device might have published a limit on the downstream load. If so, then that would govern the installation.

Secondly, and this has been debated on this forum, at length, more than once already, but I continue to assert that there is no limit to the number of receptacles you can put on a 20 amp circuit, regardless of whether you are talking commercial or residential. My basis is that nothing in 210 calls upon you to invoke the load calculations within 220, in the design of your branch circuits.

Concerning point one, I have not seen a mfg. limit on the number of downstream recs on a GFCI circuit on any recent model. I have heard that early models had this, but I do not believe any model still has this limitation.

As far as point two, I gotta look more before I agree or disagree.

 

[mivey]

Concerning point one, I have not seen a mfg. limit on the number of downstream recs on a GFCI circuit on any recent model. I have heard that early models had this, but I do not believe any model still has this limitation.

As far as point two, I gotta look more before I agree or disagree.

I don't recall a number of devices but I'm pretty sure the ones I put in this weekend had just an amp limit.

Add: The devices were 15 amp receptacles with a 20 amp feed-through rating.

 

[480sparky]

Concerning point one, I have not seen a mfg. limit on the number of downstream recs on a GFCI circuit on any recent model. I have heard that early models had this, but I do not believe any model still has this limitation.

As far as point two, I gotta look more before I agree or disagree.

Ditto. I recall Leviton having a limit many presidents ago, but I don't think they do now.

 

[Dennis Alwon]

Sorry, Dennis, but I disagree, from two perspectives. First and foremost, the manufacturer of the GFCI device might have published a limit on the downstream load. If so, then that would govern the installation.

.
You are always free to disagree. I also have not seen a limit on GFCI's in recent years. Many moons ago I believe they limited it to ten. Now keep in mind the further the distance you go the more likely you are to have problems.

Secondly, and this has been debated on this forum, at length, more than once already, but I continue to assert that there is no limit to the number of receptacles you can put on a 20 amp circuit, regardless of whether you are talking commercial or residential. My basis is that nothing in 210 calls upon you to invoke the load calculations within 220, in the design of your branch circuits.

I just have to disagree here. I understand the argument but take any electrical test and you will find out you will be marked incorrectly.

The argument is that article 220 talks of load calculation not of branch circuit design. It may be the case but many inspectors would fight you on that.

 

[jumper]

I don't recall a number of devices but I'm pretty sure the ones I put in this weekend had just an amp limit.

Add: The devices were 15 amp receptacles with a 20 amp feed-through rating.

I was about to reply for you to clarify, but then you added your edit. Now I see your point; however, you are still not limited to how many 15 amp recs you can put on that circuit. You know this better than me.

 

[jumper]

Ditto. I recall Leviton having a limit many presidents ago, but I don't think they do now.

Actually IIRC I learned about this from you.

 

[480sparky]

Actually IIRC I learned about this from you.

Oh, crap..... someone important actually thinks I'm right. The world will now start to come to an end. I guess the predictions about 2012 will come true now.

 

[charlie b]

I understand the argument but take any electrical test and you will find out you will be marked incorrectly.

I suppose that makes it a good thing that I am not going to have to take any more electrical tests. Anyway, I will not base my views on a technical question on the likelihood that I would get marked wrong on a test.

The argument is that article 220 talks of load calculation not of branch circuit design.

That is right. That, and the fact that 210 doesn?t point you to 220.

It may be the case but many inspectors would fight you on that.

They won?t have to. Although I don?t believe the NEC imposes a limit, I impose a limit of my own, when I design commercial buildings. Unless there is a special need to do otherwise, I don?t go beyond 8 general-purpose receptacles per 20 amp circuit.

 

[Dennis Alwon]

So Charlie a 12kw range in a dwelling -- what size wire would you run????and why

 

[charlie b]

So Charlie a 12kw range in a dwelling -- what size wire would you run????and why

Whatever the manufacturer states as the minimum wire size, because we are supposed to follow the manufacturer's instructions. Absent such an instruction from the manufacturer, I would go with #8 THHN, based on 210.19(A)(3), given the minimum branch circuit rating of 40 amps.

Now please do understand that I have no objection to using the calculated values from a 220 process as the basis for sizing a branch circuit. But that is different than stating that we are required to do so.

 

[Dennis Alwon]

Whatever the manufacturer states as the minimum wire size, because we are supposed to follow the manufacturer's instructions. Absent such an instruction from the manufacturer, I would go with #8 THHN, based on 210.19(A)(3), given the minimum branch circuit rating of 40 amps.

So a 16kw range can be wired with a minimum #8 and a 40 amp circuit-- that section is nutsooo but I take it you are correct. I wonder what a household range means? If it is installed in a home is it a household range? or is there a listing for it. I have seen some large ranges in homes.

 

[charlie b]

So a 16kw range can be wired with a minimum #8 and a 40 amp circuit-- that section is nutsooo but I take it you are correct.

I hereby invoke Charlie's Rule upon you. That is not what it says. What it does say is that the branch circuit cannot be smaller than 40 amp. That is not the same as saying that it is acceptable to use a 40 amp circuit.

As a design engineer, I would go through a process that would lead me to selection of a wire size and a breaker rating. But the NEC, not being a design manual, is not the tool I would use as I go through that process. I might read article 220, and I might take table 220.55 into consideration. I might even oversize the circuit, in an effort to make sure the owner does not come back to me with complaints.

 

[jumper]

So Charlie a 12kw range in a dwelling -- what size wire would you run????and why

So a 16kw range can be wired with a minimum #8 and a 40 amp circuit-- that section is nutsooo but I take it you are correct. I wonder what a household range means? If it is installed in a home is it a household range? or is there a listing for it. I have seen some large ranges in homes.

Dennis, what size is the range you are posing as an example?

Nevermind, I think I just figured out your point.

 

[mivey]

...however, you are still not limited to how many 15 amp recs you can put on that circuit.

That's true, you can wallpaper the wall if you felt froggy.

Oh, crap..... someone important actually thinks I'm right.

Anyone can make a mistake. :grin: