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Old 05-12-2011, 05:53 PM   #16
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How to Know if you have a 20 amp circuit


Manufacturers love to require 'dedicated circuits'. The NEC does not use the term. The NEC talks about "Individual branch circuits" defined as "a branch circuit that supplies only one utilization equipment." In english: A circuit with ONLY ONE appliance plugged into it...ever.

Some inspectors will require that individual branch circuits run to refrigerators have only a single receptacle. This is not specified in the NEC.

The NEC 210.21(B)(1) requires that IF a single rec is used then is must be rated not less than the individual branch circuit rating.

So, with ONE rec on a 15Amp circuit you MUST use a 15 Amp rec.
with ONE rec on a 20Amp circuit you MUST use a 20 Amp rec.

Putting a duplex rec on an 'Individual Branch circuit' does not invalidate it as an 'Individual Branch Circuit". Plugging more than one thing into that duplex rec does.

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Old 05-12-2011, 06:00 PM   #17
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How to Know if you have a 20 amp circuit


In my opinion: Manufacturers require so-called 'dedicated circuits' to limit their potential liability when people improperly use high-draw items. Also, in theory, to potentially limit their warranty coverage (BTW, I've never had that problem).... "Oh, your treadmill broke? Did you have it on a 'dedicated circuit'? No. Then we won't warranty it"
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Old 05-12-2011, 06:16 PM   #18
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How to Know if you have a 20 amp circuit


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Originally Posted by Leah Frances View Post
Manufacturers love to require 'dedicated circuits'. The NEC does not use the term. The NEC talks about "Individual branch circuits" defined as "a branch circuit that supplies only one utilization equipment." In english: A circuit with ONLY ONE appliance plugged into it...ever.

Some inspectors will require that individual branch circuits run to refrigerators have only a single receptacle. This is not specified in the NEC.

The NEC 210.21(B)(1) requires that IF a single rec is used then is must be rated not less than the individual branch circuit rating.

So, with ONE rec on a 15Amp circuit you MUST use a 15 Amp rec.
with ONE rec on a 20Amp circuit you MUST use a 20 Amp rec.

Putting a duplex rec on an 'Individual Branch circuit' does not invalidate it as an 'Individual Branch Circuit". Plugging more than one thing into that duplex rec does.
all right. Have you been studying or did you snark that from somewhere else.
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Old 05-12-2011, 06:16 PM   #19
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How to Know if you have a 20 amp circuit


I am going to have to agree with Leah, the biggest reason for the "dedicated circuit" requirement is to rule out interference to or from other equipment on the same circuit. I would doubt it is necessary to have a dedicated circuit for a treadmill. Just don't plug in other sensitive or power hungry equipment into the same circuit.

That being said your best bet for a dedicated 20amp circuit would be a window A/C unit. You are looking for a plug with a t shape on one side, probably just under a window. Which works out good because who doesn't want to workout in front of a window?
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Old 05-12-2011, 06:17 PM   #20
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How to Know if you have a 20 amp circuit


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Originally Posted by Leah Frances View Post
...
The NEC 210.21(B)(1) requires that IF a single rec is used then is must be rated not less than the individual branch circuit rating.

So, with ONE rec on a 15Amp circuit you MUST use a 15 Amp rec.
with ONE rec on a 20Amp circuit you MUST use a 20 Amp rec.

Putting a duplex rec on an 'Individual Branch circuit' does not invalidate it as an 'Individual Branch Circuit". Plugging more than one thing into that duplex rec does.
Section 210.21(B)(1) allows a 20 Amp single receptacle on a 15 Amp circuit.

20 Amp outlet is not less than 15 Amp circuit ...

This is the same section that allows a single 50 Amp outlet (range) on a 40 Amp circuit.
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Old 05-12-2011, 06:18 PM   #21
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How to Know if you have a 20 amp circuit


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all right. Have you been studying or did you snark that from somewhere else.
I've been studying. Mullin's Electrical 2008 NEC edition.
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Old 05-12-2011, 06:27 PM   #22
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How to Know if you have a 20 amp circuit


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I've been studying. Mullin's Electrical 2008 NEC edition.
ya did good except the thing kpsparky caught. If you re-read the section, you will realize why:


Quote:
The NEC 210.21(B)(1) requires that IF a single rec is used then is must be rated not less than the individual branch circuit rating.
that states the recep cannot be rated for less than the circuit. They are concerned that you do not overload the recep. The circuit will take care of itself and trip if overloaded. The recep will heat up and...

well, we don't want to go there.
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Old 05-12-2011, 06:30 PM   #23
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How to Know if you have a 20 amp circuit


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Section 210.21(B)(1) allows a 20 Amp single receptacle on a 15 Amp circuit.

20 Amp outlet is not less than 15 Amp circuit ...

This is the same section that allows a single 50 Amp outlet (range) on a 40 Amp circuit.
NOPE. That is TABLE 210.21(B)(3).

Allows 40 or 50 Amp rec on a 40 amp circuit.
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Old 05-12-2011, 06:33 PM   #24
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ya did good except the thing kpsparky caught. If you re-read the section, you will realize why:
Thanks for the complement and I still think I've got Sparky on the 40 or 50 Amp recs on 40 Amp circuits. As per the table.
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Old 05-12-2011, 06:43 PM   #25
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How to Know if you have a 20 amp circuit


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NOPE. That is TABLE 210.21(B)(3).

Allows 40 or 50 Amp rec on a 40 amp circuit.

Thanks for the complement and I still think I've got Sparky on the 40 or 50 Amp recs on 40 Amp circuits. As per the table.
Look again, Leah. Table 210.21(B)(3) is for circuits that have two or more receptacles. I stand by my original post.
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Old 05-12-2011, 06:53 PM   #26
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How to Know if you have a 20 amp circuit


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Look again, Leah. Table 210.21(B)(3) is for circuits that have two or more receptacles. I stand by my original post.
YEah, so I'm looking at that.

I'll get back at'cha. I'm not sure I'm right, right. Because, I'm no pro. Just trying to learn.
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Old 05-12-2011, 06:55 PM   #27
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How to Know if you have a 20 amp circuit


Leah, to maintain our electrical licenses, we are required to have 5 hours of continuing education per year. One of the things that was discussed in detail at one of those courses was this very topic.

Maybe you'd like to attend one such course with us sometime? You'd be surprised at what you might learn .... (of course, they ain't cheap)
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Old 05-12-2011, 08:17 PM   #28
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How to Know if you have a 20 amp circuit


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Originally Posted by kbsparky View Post
Leah, to maintain our electrical licenses, we are required to have 5 hours of continuing education per year. One of the things that was discussed in detail at one of those courses was this very topic.

Maybe you'd like to attend one such course with us sometime? You'd be surprised at what you might learn .... (of course, they ain't cheap)
Ah, education for education's sake. Sounds awesome. So this is REALLY bugging me and I've got to wrap my mind around it. I totally acknowledge that I both
a) lack the education and experience to be a pro; and
b) am smart enough to admit it

In what situations would you put a SINGLE 40 or 50 rec on a 40amp circuit? what section of the code controls this?

Just had a tiny bit of a family emergency, but I'm not dropping out because I'm not interested. Just busy.
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Old 05-12-2011, 08:44 PM   #29
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How to Know if you have a 20 amp circuit


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...In what situations would you put a SINGLE 40 or 50 rec on a 40amp circuit? ....
I already mentioned this: An electric RANGE. Many of them use a 50 Amp NEMA14-50 receptacle, wired with #8/3 romex, on a 40 Amp breaker.

FWIW, I've never seen any receptacle rated at 40 Amps. The NEMA configuration chart goes from 30 to 50.
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Old 05-12-2011, 09:00 PM   #30
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How to Know if you have a 20 amp circuit


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Originally Posted by kbsparky View Post
Leah, to maintain our electrical licenses, we are required to have 5 hours of continuing education per year. One of the things that was discussed in detail at one of those courses was this very topic.

Maybe you'd like to attend one such course with us sometime? You'd be surprised at what you might learn .... (of course, they ain't cheap)
what do ya mean they aren't cheap? Mine are free!! but I only have to take one each time Michigan accepts a new code cycle.

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