Thank you this is very helpful, I was reading the code book regarding wires smaller than the ampacity rating of the breaker on table 210-4 summary of branch circuit requirements it shows # 14 taps can be used on a circuit up to 30 amps? Is this what I think it is? the little 6" pigtails of solid wire attached to your device than wire nutted to the larger wire (usually stranded) I worked with an union electrician who did that and I said you cant do that! Looks like I might have been wrong, why in the world would than allow 14 wire on a 30amp circuit? I know to fit the device, they never taught me this in two years of electric school.

Hi Jim.
U mean 210-24 & T210-24.

I always assumed that Table 210-24 referred to taps for fixtures whips, not wiring devices.

me too Redsy, but there is a 99' change...anyone got a 99' handbook?

My '99 handbook doesn't offer any clarification over the 96 version.

Here a related post my new comment is at the end.

Posted by Craig (way-gate.merant.com,63.86.47.67) on July 19, 2001 at 06:37:20:

In Reply to: #14 awg on 30 amp!@#$% posted by Jim W on July 18, 2001 at 21:02:30:

I'm pretty sure what you refer to is a 30amp branch circuit supplying individual 15amp duplex receps. I think the underlying logic is that the device, in this case a 15a outlet, is only capable of drawing 15 amps in normal use. Therefore, the #14 pigtail will only be required to handle 15amps which is within it's ampacity. A direct short will cause a breaker trip before the wire heats sufficiently to cause fire, and since the pigtails are within a j-box, it's unlikely that there will be
flammable material to ignite anyway. Obviously this all goes to hell if some joker wires a 15amp plug to a 30amp device, but he gets what he deserves.
Posted by Jim W (papm3-02-207-79.dialup.dstream.net,216.73.207.79) on July 19, 2001 at 09:19:23:

In Reply to: Re: #14 awg on 30 amp!@#$% posted by Craig on July 19, 2001 at 06:37:20:

I think you have a track lets follow your line of thinking, a light will have fixed #14 wires but the load is known 100-600 watts, a outlet or device is rated at 15amps so #14 is ok, assuming you do not plug in more than 15 amps! The union electrician I was working with (a learning experience)was using #14 solid to attach outlets and switchs to a 20 amp branch circuit with #12 stranded wire in the emt and j-boxes, I said no-way, he says yes you can look how easy it is, as he bent the wire with his fingers. I agree it was much easier and faster also, when you stuff the box more room. But following this line of thinking why cant I string 6 15amp duplex recp. on a wall with #10 stranded in the emt, than just pigtail or "tap" the recp. with #14 solid. slap a 30amp breaker on it and whamo. Can I do this? It would have saved trouble on a stage I wired!

The problem I see is that a 30 amp ckt. requires 30 amp rated recptacles per table 210-24

I frequently put 15 amp receptacles on circuits rated 30 or 50 amps. When running Hi Bay lighting, many times the lighting is just controlled by the circuit breaker, so there is no need to run a lot of small circuits.

See 410-30(c)(2).

Makes sense since the fixture load is known and constant. Not so with general purpose receptacle outlets.

>if some joker wires a 15amp plug to a 30amp device
Or plugs two 10 amp devices into one duplex recept.

>why cant I string 6 15amp duplex recp. on a wall with #10 stranded in the emt, than just pigtail or "tap" the recp. with #14 solid. slap a 30amp breaker on it and whamo. Can I do this?
You may not go over 20 A on a general purpose circuit of that variety.

Tom, Do you fuse your fixtures when you do this?

Guys, look across the page @ Table 210-21(b)(3). You can't put a 15 amp recp on a 30 amp circ. unless as Tom pointed out, you are supplying Electric Discharge lighting with mogul-base screw shell lampholders.



[This message has been edited by electure (edited 07-20-2001).]

Look at 210-19(b). You can't use a tap to feed a duplex outlet. Note that a duplex is two receptacles. The branch circuit rating is equal to the OCPD rating. If the rating is 20 amps then the smallest conductor permited is #12.
Don(resqcapt19)

So why can you put a 15 A receptacle on a 20 A circuit but you can't feed it with a 15 A pigtail in the box?

Only on multi-outlet branches are 15 amp receptacles allowed on 20 amp ckts. I'm guessing the reason is that most equipment that would draw in excess of 15 amp would have a 20 amp plug, and not be able to be inserted anyway.

Electure,

No fusing involved. We're looking at 2- 2 1/2 feet of cord & about 6 inches of "tap" conductor to the receptacle. Tripping th OCPD for this type of circuit with a ground fault or short circuit should not be a problem. This is more or less the equivalent of the zip cord that goes to a table lamp & is plugged into a 20 amp circuit.

Tom



[This message has been edited by Tom (edited 07-20-2001).]

T210-24, under 'Circuit Rating' says Taps, ampacities of which are given to the right, substaintially less that the OCPD's above.

exactly what application does "Taps" refer to here?

The electrician I was working with would cut #14 into 6" pig tails and slice it to #12 wire and the 15 amp switch or outlet, he said they let you do this? If the device is rated at only 15 amps why not? this was on a 20 amp breaker by the way. Is this not a tap?

Isn't it necessary to use an overcurrent device rated to protect the smallest wire in the circuit (as in smallest ampacity?)

If someone plugged 2 appliances that each drew 14 amps into the receptacle (may be unlikely, but..) the insulation on the pigtails could overheat and start a fire, particularly if installed on combustible materials. My vote is that these are not taps as intended by the code.

Redsey,
The #14 tails are taps and a code violation if connected to a duplex receptacle. However I highy doubt that a 30 amp load on a #14 would get anywhere near hot enough to cause a fire.
Don(resqcapt19)

I agree with you about not causing a fire. After all, the ampacity per 310-16 is actually 25 amps (90 deg.column). However, I have felt(by hand) noticeable heat on a #12 that was running a continuous 18 amps.

Redsy,
You will feel heat. You have to remember that when you load a conductor to its full NEC ampacity, the conducotr will operate at the temperature in the ampacity table. 60°C is 140°F and that is hot to the touch.
Don

I agree with Don(resqcapt19).
Check out this graphic.

1999 NEC Code Graphic
Branch Circuit Tap Conductors, Section 210-19(d) Exception 1c
Understanding the 1999 National Electrical Code- (29KB) 2/7/00
http://www.mikeholt.com/graphics/210-19dx1c.gif

[This message has been edited by Mike W (edited 08-18-2001).]

Sorry, I made a fat finger.
Title of graphic is :
Branch Circuit Tap Conductors, Section 210-19(d) Exception 1c
Understanding the 1999 National Electrical Code- (29KB) 2/7/00

You can legally load a #14 thhn conductor to 35 amps. In Table 310-16, If the conductor is operating in an ambient temperature between 70-77 degrees F. or 21-25 C. You can appy a correction factor of 1.4 to the 25 amps under the 90 degree column. Although the LoadCenter probably wouldn't be operating in this environment, and all conductors must be sized to highest temperature it will see, but the code does show that we can use this formula for derating. Am I wrong here?

The asterisk in T310-16 refers to 240-3 which limits OCPD to 15 amps for #14. The exceptions don't include general purpose branch circuit wiring, which I believe is the idea in this thread. When using #14, The 90 deg. column is only usable for derating purposes, but still won't allow higher ampacity due to 240-3(d).



[This message has been edited by Redsy (edited 09-15-2001).]