Branch circuit load calculation kitchen equipment

[david luchini]

It does... and I already did. Here it is again...

It does not. I don't see anything in what you've quoted about what gets plugged into the receptacles. The only thing the code says about cord-and-plug-connected equipment not fastened in place is that any one piece of equipment shall not exceed 80% of the branch circuit ampere rating. Two 16A cord-and-plug loads on the same 20A is fine from a code point of view.

I'll bet the OP loads are not being unplugged from the circuit while not in use. They are therefore simultaneously-connected loads. Whether they are operated simultaneously or not does not matter. The fact they could be is all that matters.

I agree situations as you describe occur all the time on general purpose receptacle circuits which had no known [or expected] load at the design stage... but that's as far as I'll go in agreeing with you.

It doesn't matter if the loads are unplugged or not. As far as the code is concerned, the load on the circuit is 180VA for each single or multiple receptacle on one yoke. As long as you don't have more than 13 such receptacles on a 20A circuit, then the load requirement in 210.20(A) is met.

 

[david luchini]

To answer your question, this is a new building with new counter top receptacles for the coffee pot and toaster etc.. . The microwave has it own dedicated circuit as it has a special cabinet for it that was knowingly designed that way. They just put it in, but I was letting them know they will have a breaker tripping if they run those other cooking units, coffee pots and toasters etc.. at the same time on the other outlets as that was what they were planned for. I still see this as a code violation because they intended and knew what loads will be there... ie.. the toaster and coffee pot, and most likely more because history has shown that.

And if the circuit was designed for an intended load such as a coffee pot and toaster, but instead they connected a toaster oven, hot plate and radio then the circuit is in violation because whats connected is not what was intended? The counter top receptacles are there for whatever load the end user plugs in. There is nothing specific about them.

I respectfully disagree, here are the articles. And remember these are not general purpose receptacles.

Branch Circuit, General Purpose: A branch circuit that supplies two or more receptacles or outlets for lighting and appliances. It sounds to me like your counter top branch circuit fits the definition of general purpose branch circuit to a tee.

2008 NEC 210.11 Number of Branch Circuits. The minimum number of branch circuits shall be determined from the total calculated load and the size or rating of the circuits used. In all installations, the number of circuits shall be sufficient to supply the load served. In no case shall the load on any circuit exceed the maximum specified by 220.18

210.19(A)(1) General. Branch circuit conductors shall have an ampacity not less than the maximum load to be served.....
220.18 Maximum Loads. The total load shall not exceed the rating of the branch circuit....

It is a code violation to knowingly connect loads you know will exceed 100% of the branch circuit, i.e. trip the breaker!

220.10 says branch circuit loads shall be calculated as shown in 220.14. There is nothing in 220.14 about calculating the load on a branch circuit based on what is plugged into a receptacle. For receptacles, 220.14(I) tells you that the load shall be not less than 180VA for each single on multiple receptacle on one yoke. If the counter top receptacle circuit had two quadruplex receptacles, then as far as the code is concerned, the load on the circuit is 720VA. If the toaster and coffee maker get plugged in, then as far as the code is concerned, the load is STILL 720VA.

 

[Smart $]

It does not. I don't see anything in what you've quoted about what gets plugged into the receptacles. The only thing the code says about cord-and-plug-connected equipment not fastened in place is that any one piece of equipment shall not exceed 80% of the branch circuit ampere rating. Two 16A cord-and-plug loads on the same 20A is fine from a code point of view.

That is your interpretation. The code does not specifically say that... whereas it does say the maximum load cannot exceed the circuit rating. If one is 80%, all other loads cannot knowingly exceed the remaining 20%.

It doesn't matter if the loads are unplugged or not. As far as the code is concerned, the load on the circuit is 180VA for each single or multiple receptacle on one yoke. As long as you don't have more than 13 such receptacles on a 20A circuit, then the load requirement in 210.20(A) is met.

I agree... up until such time that you know what is plugged and left plugged into them. When an appliance (which is covered under Code) is left plugged into a receptacle, the receptacle is no longer a general purpose receptacle. Additionally, the term "fastened in place" is no longer used in Code.

 

[kwired]

David, I fully agree with everything you have said.

If there is problems with this installation it is design issues and not NEC violations.

 

[david luchini]

That is your interpretation. The code does not specifically say that... whereas it does say the maximum load cannot exceed the circuit rating. If one is 80%, all other loads cannot knowingly exceed the remaining 20%.

That is your interpretation. The code does not specifically say that...

The code says that the "load" for a receptacle branch circuit shall be not less than 180VA for each single or multiple receptacle on one yoke (or not less than 1va/sf total for banks and office buildings.) This is the "load" that cannot exceed the branch circuit rating.

I agree... up until such time that you know what is plugged and left plugged into them. When an appliance (which is covered under Code) is left plugged into a receptacle, the receptacle is no longer a general purpose receptacle. Additionally, the term "fastened in place" is no longer used in Code.

How does a receptacle cease being a general purpose receptacle when an appliance is plugged in?!?! The definition of General Purpose Branch Circuit say that it supplies two or more receptacles...for...appliances. That you are able to plug whatever appliance you want into the receptacle is exactly what MAKES it general purpose.

As for "fastened in place," we are still on 2005 in CT, but the NFPA online version of 2011 says: 210.23(A)(1) Cord-and-plug-equipment not Fastened in Place" and 210.23(A)(2) Utilization equipment Fastened in Place.

 

[david luchini]

David, I fully agree with everything you have said.

If there is problems with this installation it is design issues and not NEC violations.

Well said. The Code makes it clear in 90.1(C) that it is not intended to be a design specification or instruction manual.

 

[brother]

That is your interpretation. The code does not specifically say that...

The code says that the "load" for a receptacle branch circuit shall be not less than 180VA for each single or multiple receptacle on one yoke (or not less than 1va/sf total for banks and office buildings.) This is the "load" that cannot exceed the branch circuit rating.



How does a receptacle cease being a general purpose receptacle when an appliance is plugged in?!?! The definition of General Purpose Branch Circuit say that it supplies two or more receptacles...for...appliances. That you are able to plug whatever appliance you want into the receptacle is exactly what MAKES it general purpose.
[/B].

You are misquoting and misinterpeting definitions, This is an Appliance Branch Circuit not a General Purpose Branch Circuit.

2008 NEC Definitions. Appliance Branch Circuit: A branch circuit that supplies energy to one or more outlets to which appliances are to be connected and that has no permanently connected luminaires that are not a part of an appliance.

As you can see, the Nec clearly states are to be connected which is stating a person knows or has the intention of what the connected appliances (also known as a load) are to be. Again, 220.18 Maxium Load. The total load shall not exceed the rating of the branch circuit....

So to knowingly, exceeding the branch circuit rating is a code violation even if you are plugging in the appliances or radios or whatever. I could quote more articles that tell you not to exceed the branch circuit, but I see no need.


If you had a receptacle intended to be for a dishwasher appliance, and you had an idea of what the average or maxium load a diswasher would be, would you still call it a general purpose branch circuit and calculate it differently??

And if the circuit was designed for an intended load such as a coffee pot and toaster, but instead they connected a toaster oven, hot plate and radio then the circuit is in violation because whats connected is not what was intended? .

Again, you are misunderstanding and misinterpeting things. It would only be a violation if they exceed the rating of the branch circuit

The counter top receptacles are there for whatever load the end user plugs in. There is nothing specific about them.

Wrong again. If the end user exceed the rating of the branch circuit then it is a NEC violation. I also stated in my other posts that these were specifically for those counter top appliances and they knew what appliances they were putting there. This is a new building.

 

[kwired]

You are misquoting and misinterpeting definitions, This is an Appliance Branch Circuit not a General Purpose Branch Circuit.

2008 NEC Definitions. Appliance Branch Circuit: A branch circuit that supplies energy to one or more outlets to which appliances are to be connected and that has no permanently connected luminaires that are not a part of an appliance.

As you can see, the Nec clearly states are to be connected which is stating a person knows or has the intention of what the connected appliances (also known as a load) are to be. Again, 220.18 Maxium Load. The total load shall not exceed the rating of the branch circuit....

So to knowingly, exceeding the branch circuit rating is a code violation even if you are plugging in the appliances or radios or whatever. I could quote more articles that tell you not to exceed the branch circuit, but I see no need.


If you had a receptacle intended to be for a dishwasher appliance, and you had an idea of what the average or maxium load a diswasher would be, would you still call it a general purpose branch circuit and calculate it differently??



Again, you are misunderstanding and misinterpeting things. It would only be a violation if they exceed the rating of the branch circuit



Wrong again. If the end user exceed the rating of the branch circuit then it is a NEC violation. I also stated in my other posts that these were specifically for those counter top appliances and they knew what appliances they were putting there. This is a new building.

My experiences with these "break rooms" is that you often have no idea what will get plugged into any specific outlet, with some exceptions like a shelf intended for a microwave or something similar to that, but that makes the outlet dedicated to a specific appliance. The other thing you seldom know is if they have a microwave will it be 800 watt, 1000 watt, 1200 watt?

In my opinion unless they are obviously dedicated to a specific appliance they are simply general purpose outlets. Good design practice is to still run multiple circuits to the area but is not a code requirement either.

Even if they know what they will have before installation, these appliances are essentially 'disposable' anymore. 1 year later they may not have the same appliances there anymore, you may even find they have added something else later.

 

[Smart $]

That is your interpretation. The code does not specifically say that...

Only in the sense that I paraphrased it. Here's another quote...

(4) Other Loads. Branch-circuit conductors that supply
loads other than those specified in 210.2 and other than
cooking appliances as covered in 210.19(A)(3) shall have
an ampacity sufficient for the loads served and shall not be
smaller than 14 AWG.

This has the effect of limiting loads to 100%, right???

If you plug in two 16A appliances on one circuit, what is there to prevent both from operating at the same time?

The code says that the "load" for a receptacle branch circuit shall be not less than 180VA for each single or multiple receptacle on one yoke (or not less than 1va/sf total for banks and office buildings.) This is the "load" that cannot exceed the branch circuit rating.

...and the requirement of "not less than 180VA" means not less than, not 180VA no matter the conditions. Greater than 180VA per receptacle is not prohibited. And how do you convert "not less than 1VA/ft?" to a branch circuit rating?

How does a receptacle cease being a general purpose receptacle when an appliance is plugged in?!?! The definition of General Purpose Branch Circuit say that it supplies two or more receptacles...for...appliances. That you are able to plug whatever appliance you want into the receptacle is exactly what MAKES it general purpose.

That's not the issue. The issue is whether you know what may be plugged into the receptacles at the design stage, and whether you properly allowed enough VA for the receptacles on the supplying circuit. Yes, the Code has holes in it such that you can take advantage of the 180VA per receptacle requirement if you want to "shave" VA and its consequences off the service and feeder totals. If you want to take that route, that's your prerogative... but to knowingly design a likely overload condition is irresponsible, whether a violation or not.

As for "fastened in place," we are still on 2005 in CT, but the NFPA online version of 2011 says: 210.23(A)(1) Cord-and-plug-equipment not Fastened in Place" and 210.23(A)(2) Utilization equipment Fastened in Place.

My bad on that.

 

[kwired]

If you plug in two 16A appliances on one circuit, what is there to prevent both from operating at the same time?

If I am the installer and I don't know the users intend to plug two 16A appliances into one circuit, I am still code compliant because I have proper overcurrent protection on the circuit. If the user get tired of resetting breaker they can call me and I will install an additional code compliant circuit.

15 and 20 amp 125 volt receptacles are easy to overload, so much equipment out there that uses that configuration.

Even in places where code tells us certain receptacles are to be on specific circuits, like SABC, dwelling bath receptacles, dwelling laundry circuit, you can still encounter situations where the user will plug in more load than maybe expected, but protection is still provided by a properly sized overcurrent device.

A receptacle for a dedicated appliance? At installation I may know there will be a microwave plugged in to an outlet. I most likely will not know if it will be a 600 watt model or a 1300 watt model.

 

[Smart $]

If I am the installer and I don't know the users intend to plug two 16A appliances into one circuit, I am still code compliant because I have proper overcurrent protection on the circuit. If the user get tired of resetting breaker they can call me and I will install an additional code compliant circuit.

15 and 20 amp 125 volt receptacles are easy to overload, so much equipment out there that uses that configuration.

Even in places where code tells us certain receptacles are to be on specific circuits, like SABC, dwelling bath receptacles, dwelling laundry circuit, you can still encounter situations where the user will plug in more load than maybe expected, but protection is still provided by a properly sized overcurrent device.

A receptacle for a dedicated appliance? At installation I may know there will be a microwave plugged in to an outlet. I most likely will not know if it will be a 600 watt model or a 1300 watt model.

...and I agree with you, for I believe you will not calculate the microwave receptacle at 180VA or knowingly subject that circuit to an overload condition, yes?

 

[kwired]

...and I agree with you, for I believe you will not calculate the microwave receptacle at 180VA or knowingly subject that circuit to an overload condition, yes?

Yes, but that is by design and not necessarily because of code.

 

[david luchini]

You are misquoting and misinterpeting definitions, This is an Appliance Branch Circuit not a General Purpose Branch Circuit.

2008 NEC Definitions. Appliance Branch Circuit: A branch circuit that supplies energy to one or more outlets to which appliances are to be connected and that has no permanently connected luminaires that are not a part of an appliance. .

How can I be misquoting when I quoted the code directly?:? You will notice that the word "receptacle" is nowhere to be found in "Appliance Branch Circuit" definition. This is a General Purpose Branch Circuit by the definition in the code.

As you can see, the Nec clearly states are to be connected which is stating a person knows or has the intention of what the connected appliances (also known as a load) are to be. Again, 220.18 Maxium Load. The total load shall not exceed the rating of the branch circuit....

220.18 says the total load connect exceed the rating of the branch circuit....and the load is calculated per 220.14. And 220.14(I) Receptacle Outlets says receptacles outlets shall be calculated at not less than 180VA per single or multiple receptacle on one yoke. Unless you have more than 13 receptacle outlets on your circuit, you are NOT exceeding the rating of the branch circuit in accordance with 220.18.

So to knowingly, exceeding the branch circuit rating is a code violation even if you are plugging in the appliances or radios or whatever. I could quote more articles that tell you not to exceed the branch circuit, but I see no need.

Yes, to knowingly install more than 13 receptacle outlets on a 20A branch circuit would be a code violation. This would be exceeding the rating of the branch circuit. The end user plugging in appliance with a total rating that would exceed the branch circuit rating is not.

Wrong again. If the end user exceed the rating of the branch circuit then it is a NEC violation. I also stated in my other posts that these were specifically for those counter top appliances and they knew what appliances they were putting there. This is a new building.

This is incorrect. The code applies to the installation of the conductors, raceways and equipment for the premise wiring system. The code is silent as to what the end user may or may not plug into the receptacles.

 

[Little Bill]

How can I be misquoting when I quoted the code directly?:? You will notice that the word "receptacle" is nowhere to be found in "Appliance Branch Circuit" definition. This is a General Purpose Branch Circuit by the definition in the code.



220.18 says the total load connect exceed the rating of the branch circuit....and the load is calculated per 220.14. And 220.14(I) Receptacle Outlets says receptacles outlets shall be calculated at not less than 180VA per single or multiple receptacle on one yoke. Unless you have more than 13 receptacle outlets on your circuit, you are NOT exceeding the rating of the branch circuit in accordance with 220.18.



Yes, to knowingly install more than 13 receptacle outlets on a 20A branch circuit would be a code violation. This would be exceeding the rating of the branch circuit. The end user plugging in appliance with a total rating that would exceed the branch circuit rating is not.




This is incorrect. The code applies to the installation of the conductors, raceways and equipment for the premise wiring system. The code is silent as to what the end user may or may not plug into the receptacles.

.:thumbsup:

 

[Smart $]

How can I be misquoting when I quoted the code directly?:? You will notice that the word "receptacle" is nowhere to be found in "Appliance Branch Circuit" definition. This is a General Purpose Branch Circuit by the definition in the code.

Doesn't matter. The definition of appliance branch circuit uses the term "outlet". A receptacle is but one form of an outlet.

Nonetheless, if you are going to insist on this being a General Purpose Branch Circuit, I quote you 220.14 general statement...

220.14 Other Loads ? All Occupancies. In all occupancies,
the minimum load for each outlet for general-use receptacles
and outlets not used for general illumination shall
not be less than that calculated in 220.14(A) through (L),
the loads shown being based on nominal branch-circuit
voltages.

And here is 220.14(A)...

(A) Specific Appliances or Loads. An outlet for a specific
appliance or other load not covered in 220.14(B) through
(L) shall be calculated based on the ampere rating of the
appliance or load served.

So why do we have a section about specific appliances or loads in a section about general-use receptacles and outlets???

 

[david luchini]

Doesn't matter. The definition of appliance branch circuit uses the term "outlet". A receptacle is but one form of an outlet.

Nonetheless, if you are going to insist on this being a General Purpose Branch Circuit, I quote you 220.14 general statement...

I only insist, because the circuit in question meets the definition of General Purpose Branch Circuit to a tee.

As far as 220.14 it says:

220.14 Other Loads ? All Occupancies. In all occupancies,
the minimum load for each outlet for general-use receptacles
and outlets not used for general illumination shall
not be less than that calculated in 220.14(A) through (L),
the loads shown being based on nominal branch-circuit
voltages.

And here is 220.14(A)...

(A) Specific Appliances or Loads. An outlet for a specific
appliance or other load not covered in 220.14(B) through
(L) shall be calculated based on the ampere rating of the
appliance or load served.

And this load is specifically covered in 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 voltamperes for each receptacle. This provision shall not be applicable to the receptacle outlets specified in 210.11(C)(1) and (C)(2).

You are free to calculate the load at greater than 180VA per receptacles(s) on a single yoke, but you are not required to.

 

[Smart $]

I only insist, because the circuit in question meets the definition of General Purpose Branch Circuit to a tee.

...and I'm going with the "general" flow of that, for the sake of this discussion...

As far as 220.14 it says:
...
And here is 220.14(A)...
...
And this load is specifically covered in 220.14(I):

The problem is, a receptacle is not a load. The Code is only telling you to calculate a load when you don't know what will get plugged into the receptacles on the circuit. What is being covered in 220.14(I) is the unknown load which may or may not get plugged into each recptacle, not the receptacle itself. Otherwise, you could run as many receptacles as you want and not count any as ever having a load plugged into it.

You are free to calculate the load at greater than 180VA per receptacles(s) on a single yoke, but you are not required to.

But you are required to, and that is exactly why 220.14(A) is in a section about general-use receptacles and outlets...

If I as the owner tell you at or before the design stage, the breakroom will have cabinets and counter on one wall, and a 1000W microwave on the counter, you can run general-purpose receptacles for the whole countertop... but you have to calculate, for that circuit, one receptacle for the microwave. Not 100% efficient let's say its ampere rating equates to 1200VA. You plan a 20A circuit, good for 2400VA. Thus 1200VA for the microwave and 1200VA left for the other receptacles on the circuit. 1200VA ? 180VA = 6.7. That means you can have a total of 6+1 = 7 receptacles on that circuit (assuming you know nothing else specifically will be plugged into that circuit, even though you presume something will be eventually)... and the point is, the microwave can be plugged into any receptacle for the countertop.

 

[kwired]

...and I'm going with the "general" flow of that, for the sake of this discussion...


The problem is, a receptacle is not a load. The Code is only telling you to calculate a load when you don't know what will get plugged into the receptacles on the circuit. What is being covered in 220.14(I) is the unknown load which may or may not get plugged into each recptacle, not the receptacle itself. Otherwise, you could run as many receptacles as you want and not count any as ever having a load plugged into it.


But you are required to, and that is exactly why 220.14(A) is in a section about general-use receptacles and outlets...

If I as the owner tell you at or before the design stage, the breakroom will have cabinets and counter on one wall, and a 1000W microwave on the counter, you can run general-purpose receptacles for the whole countertop... but you have to calculate, for that circuit, one receptacle for the microwave. Not 100% efficient let's say its ampere rating equates to 1200VA. You plan a 20A circuit, good for 2400VA. Thus 1200VA for the microwave and 1200VA left for the other receptacles on the circuit. 1200VA ? 180VA = 6.7. That means you can have a total of 6+1 = 7 receptacles on that circuit (assuming you know nothing else specifically will be plugged into that circuit, even though you presume something will be eventually)... and the point is, the microwave can be plugged into any receptacle for the countertop.

The fine line here is just when is the receptacle intended for a specific load, and when is it just for general purpose?

If you know they are going to have a microwave, coffee maker and toaster - you still don't know what kind of demand there will be from each. If only a few people use this break room frequently, one circuit may never give problems, if used by many you may need three circuits for these three items alone to keep from having breaker tripping issues.

You can have same floor plan for 10 different facilities, with same dimensions and receptacle placement in all 10. The end users may have 10 different combinations of loads plugged into those same receptacles, especially those on a countertop in a break room. A place designed and intended for a refrigerator or a shelf or cabinet intended to place a microwave may be items that are same or at least very similar in all 10 installations. IMO they are general purpose outlets, but good design takes into consideration how they may be loaded.

 

[Smart $]

The fine line here is just when is the receptacle intended for a specific load, and when is it just for general purpose?

...

But that's just it, the whole circuit of receptacles is for general use... until reduced to one receptacle .

Code requires a minimum two 20A SABC's for dwellings calculated at 1500VA each for a reason, yet gives non-dwellings a bit of leeway. In my experience, a breakroom will at times, given the conveniences we take for granted in our homes, be put to simultaneous use the same if not more than in a home.

A maintenance shop I've worked in a couple times in as many years has 4 microwaves on the same circuit (and of all places, a 2.4MW power plant ). There is shall we say no scheduled lunch time, but it never fails that during shutdowns when the staff has been augmented, at some point all 4 microwaves will be put to use, and you can guess the rest... :angel:

 

[brother]

How can I be misquoting when I quoted the code directly?:? You will notice that the word "receptacle" is nowhere to be found in "Appliance Branch Circuit" definition. This is a General Purpose Branch Circuit by the definition in the code..

You did not quote code directly. I say you were misquoting the definition because you left out the part of the General Purpose Branch circuit definition that specifically distinguishes it from the Appliance Branch Circuit definition. That word is lighting or luminaires. Just because the word "receptacle" is not in Appliance branch circuit definition does not mean it is limited without one. It is still an "outlet", .

Here are the 2 different definitions specifically.

Appliance Branch Circuit: A branch circuit that supplies energy to one or more outlets to which appliances are to be connected and that has no permanently connected luminaires that are not a part of an appliance.

General Purpose Branch circuit: A branch circuit that supplies two or more receptacles or outlets for lighting and applicances.

The NEC would have not added Appliance Branch circuit definition if every outlet or receptacle was a 'General Purpose'. Remember these outlets were intended specifically for these appliances so it would meet the definition of Appliance Branch Circuit definition to a tee!. If that was not the intended purpose you may have a basis of argument. I agree with Smart$

Doesn't matter. The definition of appliance branch circuit uses the term "outlet". A receptacle is but one form of an outlet.

This is incorrect. The code applies to the installation of the conductors, raceways and equipment for the premise wiring system. The code is silent as to what the end user may or may not plug into the receptacles.

I know this is an age old debate, on whether the NEC extends beyond the outlet or receptacle and affects the end user. I believe you are incorrect. The code does speak to the end user in many situations on what may or may not be plug into the receptacles. 2008 NEC 422.51 on vending machines come to mind, or 422.45 or 590 that deals with holiday lights. Another code section is 210.21(B)(2) Total Cord and Plug Connected Load.

Whether the end user knows the NEC or not, this does not change the fact that the NEC applies or has been violated on occassion. You also misquoted 90.2 . Read it again, it is not just limited to premise wiring, it also says in (3) Installations of conductors and equipment that connect to the supply of electricity. No where will you find in the NEC where it says it will NOT apply to the end user or what may be plugged into receptacles.

So when these outlets(receptacles) are intended for coffee pots and toasters that exceed the 20 amp branch circuit, the moment someone plug them in and turn them on and exceed the rating, it is a violation.