NEC clause

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electrics

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it says in a book about NEC "The rating of the branch circuit is determined by the size of the
overcurrent protection device. An individual receptacle on a single branch
circuit cannot have an amperage that is less than the rating of the OCPD,
as specified in NEC Article 210.21(B"

so isnt it false? you have a 20 A receptacle and the circuit is 15 A so you cant operate ur device
am i wrong?
 
electrics said:
it says in a book about NEC "The rating of the branch circuit is determined by the size of the
overcurrent protection device. An individual receptacle on a single branch
circuit cannot have an amperage that is less than the rating of the OCPD,
as specified in NEC Article 210.21(B"

so isnt it false? you have a 20 A receptacle and the circuit is 15 A so you cant operate ur device
am i wrong?
Click to expand...

Not real sure if I'm following but per 210.21(B)(1) this is referring to a single receptacle on a branch circuit. Ok the 20amp receptacle is fine because it adhere's to this article. The branch circuit would be limited to 15amp due to the OCPD; so the 20amp receptacle would never see 20amps. The max load on the circuit would be limited to 15amp.
 
so you cant use a load of which amperage is same with its receptacle never? i guess it has to do with the fact that there is a clause there again as "the maximum load on any
given circuit is 80 percent of the receptacle rating and circuit rating"
i got it sir...
 
electrics said:
so you cant use a load of which amperage is same with its receptacle never?
Click to expand...
Sure you can.
electrics said:
i guess it has to do with the fact that there is a clause there again as "the maximum load on any
given circuit is 80 percent of the receptacle rating and circuit rating"
i got it sir...
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The 80% in T 210.21(B)(2) would only come into play for more than one receptacle, as in a duplex receptacle or more. A single receptacle can be loaded to 100%.

Roger
 
roger said:
Sure you can. The 80% in T 210.21(B)(2) would only come into play for more than one receptacle, as in a duplex receptacle or more. A single receptacle can be loaded to 100%.

Roger
Click to expand...

but if you load it to % 100 of the receptacle so olpd will cut the line isnt it?
 
electrics said:
but if you load it to % 100 of the receptacle so olpd will cut the line isnt it?
Click to expand...

No, the OCPD will also hold 100% of the load and is allowed to for non-continuous loads, (less than 3 hours) see 210.19(A) and 210.20(A)

Roger
 
210.21(B)(3) is the point. So why are these receptacles (more than 1 )not allowed to load up to circuit rating ?? is there any special reason?
 
i also want to draw ur consideration that in this clause cited that it is just up to 50 A and above that receptacle ratings are not less than circuit ratings, also for single receptacles 210.21.B.1 cites it is always "not less than circuit ratings " is it true till now??
 
what is also cord-and-plug connected devices? for example refrigerator one of them?? what is it exacty? can we say everything which has a plug counts??
 
electrics said:
it says in a book about NEC "The rating of the branch circuit is determined by the size of the
overcurrent protection device.
Click to expand...
I don't believe this to be true. You can have a branch circuit OCPD of 50 amps feeding an a/c unit with a #10 wire. This circuit is only as good as it's weakest link. In this case the #10.

An individual receptacle on a single branch
circuit cannot have an amperage that is less than the rating of the OCPD,
as specified in NEC Article 210.21(B"
so isnt it false? you have a 20 A receptacle and the circuit is 15 A so you cant operate ur device
Click to expand...
Look at table 210.21(B)(3) a 15 amp circuit must utilize a receptacle rating of not over 15 amps
 
nec 220.12 gives a table and says general lighting load, here in terminology i meani lighting load includes also laundry and appliances too? or just illumination loads?
 
in short i want to ask you this;
in table 220.42 it says lighting load demand factors and this book finds the general lighting load multiplying area and 3 kva and adding 1 laundry and 2 small appliances, so what is the difference between these two tables? is the first one an avarage or minimum or maximum load and is this only fixtures and general use receptacles?? also with second table a demand factor is used so i think the first table gives a maximum power and not an avarage or minimum load ? also if they are about lighting loads so why we add receptacles such as general use laundry and small appliances? where is " lighting"? pls tell me what is up here?
 
electrics-- you ask many questions at once and I find it very hard to follow your thought. In the post above you mention T220.42 then you ask what the difference is between the Tables?-- What Tables you mentioned only one Table.
 
electrics said:
nec 220.12 gives a table and says general lighting load, here in terminology i meani lighting load includes also laundry and appliances too? or just illumination loads?
Click to expand...
I had given the other table above, excuse me, anyway can u tell me what is the difference between these tables...
 
electrics said:
it says in a book about NEC "The rating of the branch circuit is determined by the size of the overcurrent protection device.
Click to expand...
It says that in the NEC itself also. See 210.3.
electrics said:
An individual receptacle on a single branch circuit cannot have an amperage that is less than the rating of the OCPD, as specified in NEC Article 210.21(B). So isn?t it false? You have a 20 A receptacle and the circuit is 15 A so you can?t operate your device. Am I wrong?
Click to expand...
Yes, you are wrong. You have the ?which is bigger than which? part wrong. For an individual branch circuit, a 20 amp receptacle can be on a 15 amp circuit, but a 15 amp receptacle cannot be on a 20 amp circuit.

To be clear, we are talking about an individual branch circuit. That means there is one, and only one load. If you are dealing with a duplex receptacle, that counts as two. So 210.21(B)(1) does not apply to a duplex.
 
electrics said:
in short i want to ask you this;
Click to expand...
Please do not ask a second question in the same thread, if it is not related to the original question. It confuses your readers. Start a separate thread next time.

Table 220.12 tells us how much to allow for lighting loads. Table 220.42 gives us demand factors that we can apply to lighting loads. 220.52(A) tells us we can add the small appliance load to the lighting load, before applying the demand factors. 220.52(B) says the same thing about the laundry circuit load.
 
Not an NEC answer, to your (first) question, but think of it logically. If you have a branch circuit protected at twenty amps and it feeds a single receptacle, then whatever is plugged into that single receptacle could draw the full 20 amps through that device. However, if you have more than one receptacle on that circuit the total load of the circuit could be divided between each receptacle. It could be argued that recep. #1 could allow a load of 19 amps and recep. 2 could allow a load of 1 amp, and if both receps. were only 15 amp models, that you would be over that devices limit.

Personally I interpret the code section to mean that if one "duplex receptacle" or one device is on the circuit, then you must have a device of the same rating. Most people don't share my view, however and refer to a single receptacle on one device yoke.
 
Article 90.1 said:
Not an NEC answer, to your (first) question, but think of it logically. If you have a branch circuit protected at twenty amps and it feeds a single receptacle, then whatever is plugged into that single receptacle could draw the full 20 amps through that device. However, if you have more than one receptacle on that circuit the total load of the circuit could be divided between each receptacle. It could be argued that recep. #1 could allow a load of 19 amps and recep. 2 could allow a load of 1 amp, and if both receps. were only 15 amp models, that you would be over that devices limit.

Personally I interpret the code section to mean that if one "duplex receptacle" or one device is on the circuit, then you must have a device of the same rating. Most people don't share my view, however and refer to a single receptacle on one device yoke.
Click to expand...

The code is clear that you can have a 15 amp duplex receptacle on a 20 amp circuit. It's also clear that you can have a 20 amp single receptacle on a 15 amp circuit. In either case the OCPD would protect the circuit from overload just as it would if you had 5-15 amp duplex receptacles on a circuit and plugged in and ran 5-5 amp loads simulataneously. IMO your personal interpretations are not supported by the NEC.
 
Article 90.1 said:
Personally I interpret the code section to mean that if one "duplex receptacle" or one device is on the circuit, then you must have a device of the same rating. Most people don't share my view, however and refer to a single receptacle on one device yoke.
Click to expand...

Most people do not agree becuse your interpretaion is incorrect.

infinity said:
The code is clear that you can have a 15 amp duplex receptacle on a 20 amp circuit.
Click to expand...

I agree, it is very clear on that.

IMO your personal interpretations are not supported by the NEC.
Click to expand...

I agree on this as well. :)
 
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