NEC requirements

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ammklq143 said:
You wouldn't happen to have a code reference for the number of receptacles on a circuit would you?
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I don't know your Code that you are working out of. My answer is based on the 2014 NEC. The basic reference is to 220.14(J).

Consider the house in your opening post. To figure out the 2014 NEC minimum wiring configuration we follow specific guidelines for receptacles, luminaires and switches as laid out in 210. However, for sizing the service and arriving at the minimum number of circuits, we do the calculation laid out in Article 220.

Start with 220.12 to see the requirement to measure from the outside dimensions of the dwelling when calculating floor area. The informational note to 220.12 taken with 90.1(B) says that the calculation may well end up with a Premises Wiring (System) that the homeowner will not find adequate, and that is OK because it will be "essentially free from hazard." Note the floor areas described in 220.12 that don't have to be included in the dwelling total floor area.

The rule of 220.12 refers you to Table 220.12 where you will find the General Lighting Load requirement to be 3 Watts per square foot. Considering the house you describe in your opening post (OP) multiply the calculated square feet by 3 Watts per square foot to get the Wattage of the General Lighting Load. This is a minimum amount required by the NEC for your specific house. Lets say your house has 1500 square feet by calculation from 220.12. 3 Watts/Sq Ft times 1500 Sq Ft = 4500 Watts.

NOTE: The line name "Dwelling unit" in Table 220.12 has a superscript "a". Follow the superscript "a" to the bottom of Table 220.12 and you will read "See 220.14(J)".

In reading 220.14(J), to me, the most important phrase is "No additional calculations shall be required for such outlets." 220.14(J) (1), (2) & (3) take a while to read and understand the specific outlets that are included under 220.14(J).

Now, here is where we work back to the number of Outlets allowed on a General Lighting Load branch circuit in your OP house. A 20 Amp 120 Volt over current protective device lets through 2400 Watts. How many 20 Amp branch circuits will provide a minimum of the 4500 Watt calculated General Lighting Load in your house? The answer is: divide 4500 by 2400 and round up to the next whole number. The result is "Two". Two 20 Amp 120 Volt branch circuits will provide the MINIMUM amount of power for the "General Lighting Outlets" described in 220.14(J) for the 1500 Sq Ft of your house. In your case, dividing 1500 Sq Ft by 2 circuits yields 750 Sq Ft per 20 Amp General Lighting branch circuit.

For your house that you ask about in the OP, let's consider the floor area of the bedrooms, bed closets, hallway, living room, etc., summing them to a total of 750 Sq. Ft. In these areas, all the General Lighting outlets present (as required by Article 210) are the MINIMUM number of outlets that can be on that one 20 Amp General Lighting branch circuit of 20 Amps.

When I get to this point, I can see that 750 Sq Ft is a large area, and, in the bedrooms, and similar areas, there are no other branch circuits that are REQUIRED (like the Small Appliance branch circuits, or the furnace circuit, laundry circuit, etc.). Pretty much ALL the outlets present need only be supplied by the minimum number of calculated General Lighting Load circuits.

There is no fixed "receptacle" max count per circuit for a Dwelling General Lighting Load branch circuit.

I, personally, find it pretty easy to add an additional branch circuit or two, to split up the 750 Sq Ft area into smaller areas but that is a design choice of mine and is not required by the minimum of the NEC. If the person or business that is paying me only wants the absolute minimum wiring package, this is how stripped down and bare the Premises Wiring (System) can be. As 90.1 says, it may not be "adequate".

dkidd said:
I have seen that position before, but NEC does not require that.
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What do you find the NEC to require in "that position"?
 
On your way to read 220.14(J) as described above, stop by 220.14(I) which covers receptacles other than as covered in 221.14(J) & (K) and calls for using 180va for receptacles per yoke.
This is normally the base for the misunderstanding that dwelling unit receptacles should be figured at 180va.
 
al hildenbrand said:
I don't know your Code that you are working out of. My answer is based on the 2014 NEC. The basic reference is to 220.14(J).

Consider the house in your opening post. To figure out the 2014 NEC minimum wiring configuration we follow specific guidelines for receptacles, luminaires and switches as laid out in 210. However, for sizing the service and arriving at the minimum number of circuits, we do the calculation laid out in Article 220.

Start with 220.12 to see the requirement to measure from the outside dimensions of the dwelling when calculating floor area. The informational note to 220.12 taken with 90.1(B) says that the calculation may well end up with a Premises Wiring (System) that the homeowner will not find adequate, and that is OK because it will be "essentially free from hazard." Note the floor areas described in 220.12 that don't have to be included in the dwelling total floor area.

The rule of 220.12 refers you to Table 220.12 where you will find the General Lighting Load requirement to be 3 Watts per square foot. Considering the house you describe in your opening post (OP) multiply the calculated square feet by 3 Watts per square foot to get the Wattage of the General Lighting Load. This is a minimum amount required by the NEC for your specific house. Lets say your house has 1500 square feet by calculation from 220.12. 3 Watts/Sq Ft times 1500 Sq Ft = 4500 Watts.

NOTE: The line name "Dwelling unit" in Table 220.12 has a superscript "a". Follow the superscript "a" to the bottom of Table 220.12 and you will read "See 220.14(J)".

In reading 220.14(J), to me, the most important phrase is "No additional calculations shall be required for such outlets." 220.14(J) (1), (2) & (3) take a while to read and understand the specific outlets that are included under 220.14(J).

Now, here is where we work back to the number of Outlets allowed on a General Lighting Load branch circuit in your OP house. A 20 Amp 120 Volt over current protective device lets through 2400 Watts. How many 20 Amp branch circuits will provide a minimum of the 4500 Watt calculated General Lighting Load in your house? The answer is: divide 4500 by 2400 and round up to the next whole number. The result is "Two". Two 20 Amp 120 Volt branch circuits will provide the MINIMUM amount of power for the "General Lighting Outlets" described in 220.14(J) for the 1500 Sq Ft of your house. In your case, dividing 1500 Sq Ft by 2 circuits yields 750 Sq Ft per 20 Amp General Lighting branch circuit.

For your house that you ask about in the OP, let's consider the floor area of the bedrooms, bed closets, hallway, living room, etc., summing them to a total of 750 Sq. Ft. In these areas, all the General Lighting outlets present (as required by Article 210) are the MINIMUM number of outlets that can be on that one 20 Amp General Lighting branch circuit of 20 Amps.

When I get to this point, I can see that 750 Sq Ft is a large area, and, in the bedrooms, and similar areas, there are no other branch circuits that are REQUIRED (like the Small Appliance branch circuits, or the furnace circuit, laundry circuit, etc.). Pretty much ALL the outlets present need only be supplied by the minimum number of calculated General Lighting Load circuits.

There is no fixed "receptacle" max count per circuit for a Dwelling General Lighting Load branch circuit.

I, personally, find it pretty easy to add an additional branch circuit or two, to split up the 750 Sq Ft area into smaller areas but that is a design choice of mine and is not required by the minimum of the NEC. If the person or business that is paying me only wants the absolute minimum wiring package, this is how stripped down and bare the Premises Wiring (System) can be. As 90.1 says, it may not be "adequate".



What do you find the NEC to require in "that position"?
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I personally think you have to do a little reading between the lines to get a minimum number of required circuits, but good design choices usually gives you well over that minimum anyway.
 
kwired said:
I personally think you have to do a little reading between the lines to get a minimum number of required circuits, but good design choices usually gives you well over that minimum anyway.
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210.11,especially A spells it out pretty well.
 
dkidd said:
210.11,especially A spells it out pretty well.
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Clear as mud.

Only thing you can get out of that is for a 1500 SF home they want at least 4500 VA accounted for in load calculations for general lighting and receptaces and that you can divide that across 15 or 20 amp circuits. In general there is no good way to determine what will be loaded heavily and what will be idle most of the time. One occupant may be almost the opposite with their usage as the next one in the same setting.

Keep in mind when calculating at the branch circuit level (which would be a part of the question of "how many outlets on a circuit"), we have already excluded the dedicated circuits that have a fixed load, though we may have some fixed loads with other outlets in some cases as well, usually the fixed load is required to be 50% or less of the branch circuit rating.

Divide that 4500 VA evenly across the circuits you install? Good luck, the load diversity will change faster then you can recalculate things sometimes.
 
kwired said:
I personally think you have to do a little reading between the lines to get a minimum number of required circuits, but good design choices usually gives you well over that minimum anyway.
dkidd said:
210.11,especially A spells it out pretty well.
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:?
Well, ah, OK. I wasn't talking about the number of required dwelling circuits. Nor was the OP's follow up question. Here's the question again:

ammklq143 said:
You wouldn't happen to have a code reference for the number of receptacles on a circuit would you?
Thanks
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I specifically chose to address, in my reply, the General Lighting branch circuits in a Dwelling.

The short answer is that for any one specific dwelling there is a "number" of receptacles per General Lighting branch circuit that can be derived from (A) the required outlets from Article 210 and (B) the calculations of Article 220.

However, this "number" of receptacles is neither a maximum nor a minimum for use in a "Rule of Thumb" to answer Ammklq143's question.

The important point about Article 210 and Article 220 General Lighting Circuits is, there is no NEC language that directly limits the number of receptacle outlets on dwelling General Lighting Circuits.
 
al hildenbrand said:
The important point about Article 210 and Article 220 General Lighting Circuits is, there is no NEC language that directly limits the number of receptacle outlets on dwelling General Lighting Circuits.
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That has been my understanding all along. You may be able to read between the lines or jump back and forth to conclude there may be a minimum number of circuits required, but nothing says you can only have X number of outlets on one circuit on the general lighting circuits.

Some think you are limited to 180 VA per outlet on non dwelling outlets - but I don't think that is true either, for similar reasons - you don't know what the load will be, and it can change faster then you can calculate it sometimes.
 
al hildenbrand said:
....The important point about Article 210 and Article 220 General Lighting Circuits is, there is no NEC language that directly limits the number of receptacle outlets on dwelling General Lighting Circuits.
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Beware! This fact is terrifying to some people and can cause uncontrollable hand wringing when it is discussed in their presence.
 
ammklq143 said:
I did find the code referring to the dining room receptacles. 210.52(b) I looked at my 2008 book and at that time they weren't required to be on the SABC. I think they COULD be but weren't required. That was before the SABC's were required to have arc fault protection but at that time the dining rooms did have to unless they were included on a SABC. Thanks for the help.
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From the 2008 NEC:

Small Appliances.
(1) Receptacle Outlets Served.

In the kitchen, pantry, breakfast room, dining room, or similar area of a dwelling unit, the two or more 20-ampere small-appliance branch circuits required by 210.11(C)(1) shall serve all wall and floor receptacle outlets covered by 210.52(A), all countertop outlets covered by 210.52(C), and receptacle outlets for refrigeration equipment.

Been that way since the 50's I believe, probably because coffee makers and food warmers were popular back then in dining rooms.

In 2008 AFCI was only required on bedroom circuits.

-Hal
 
hbiss said:
Been that way since the 50's I believe, probably because coffee makers and food warmers were popular back then in dining rooms.
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Yup. I agree. The first Code I tested on to become a journeyman was the 1965 and Dining Room receptacles were required to be on a 20 Amp branch circuit that had no other outlets and could be a Small Appliance Branch Circuit.

This requirement is over half a century old.
 
I concur with all concurrences.


Years ago, wiring a house in a town I'd never worked in, inspector looked at my dining room branch and said, "you could've just hit that off the living room."

Me, explains code, inspector says, "I could never get away with enforcing that here."

Really?!


Sent from my iPhone using Tapatalk
 
A dining outlet related funny story:

We did a really big, fancy, custom house on Lake Minnetonka (where the rich folks live in MN) when I was an apprentice. There was a designer holding the owners hand through the whole thing.

The journeyman was doing the rough-in walk through with them and they were discussing if they wanted receptacles above some built in cabinetry in the formal dining room. The designer asked why they would want them, for what purpose? The journeyman said in case they wanted to plug something in on that countertop, like a crock pot. The designer got this super-appalled look on her face and exclaimed, "A CROCK POT?! IN THE FORMAL DINING ROOM?!" The journeyman was totally caught off guard and just stood there, dumbfounded.

A second later, the framing carpenter yelled from the other room, "Go back to your double-wide, sparky!!"

Both the GC and I had to duck into the garage to avoid busting out in front of everyone. I nearly wet myself I was laughing so hard! It still makes me laugh! :lol::lol::lol:
 
ghorwood said:
Why would anyone pull wire to outlet boxes, and not make up the splices? IMHO, it makes trim out that much quicker. Just sayin'.
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Because a majority of them have nothing to make except for the EGC. All the other connections are on the device whenever you do install it.
 
ammklq143 said:
I did find the code referring to the dining room receptacles. 210.52(b) I looked at my 2008 book and at that time they weren't required to be on the SABC. I think they COULD be but weren't required. That was before the SABC's were required to have arc fault protection but at that time the dining rooms did have to unless they were included on a SABC. Thanks for the help.
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It was not optional in the 2008 code.
(B) Small Appliances.
(1) Receptacle Outlets Served. In the kitchen, pantry, breakfast room, dining room, or similar area of a dwelling unit, the two or more 20-ampere small-appliance branch circuits required by 210.11(C)(1) shall serve all wall and floor receptacle outlets covered by 210.52(A), all countertop outlets covered by 210.52(C), and receptacle outlets for refrigeration equipment.
Click to expand...
 
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