• Welcome to the new and improved Building Code Forum. We appreciate you being here and hope that you are getting the information that you need concerning all codes of the building trades. This is a free forum to the public due to the generosity of the Sawhorses, Corporate Supporters and Supporters who have upgraded their accounts. If you would like to have improved access to the forum please upgrade to Sawhorse by first logging in then clicking here: Upgrades

Tap Rule in Residential

jar546

jar546

Forum Coordinator
Joined
Oct 16, 2009
Messages
11,103
Location
Somewhere Too Hot & Humid
Is it legal to use a 14awg wire in a basement for a lighting switch leg if the basement is on a dedicated 20A circuit and the rest of the wiring is 12awg?

Table 210.24 appears to support this?



Hmmmmmmm
 
No the switch leg is part of the circuit and must be 12 awg in your case. 240.4(D)(5) limits 20 at 12 gauge.

Look at 210.20(B)

Many get confused by article 240.5(B)(2)-- but that is the fixture wire not the switch leg
 
Dennis said:
No the switch leg is part of the circuit and must be 12 awg in your case. 240.4(D)(5) limits 20 at 12 gauge. Look at 210.20(B)

Many get confused by article 240.5(B)(2)-- but that is the fixture wire not the switch leg
Click to expand...
I must agree with you on this and I posted this for a reason. The training that the local IBEW has been getting tells them this is an approved method.
 
Last edited by a moderator:
As Dennis said it's definitely a no-no. Only 12gauge wiring can be used anyplace on a 20 amp circuit, a 14 games is used anyplace the circuit would have to be degraded to a 15 circuit and even then mixing 12 and 14gauge is frowned upon. I've seen several situations where a inspector made a contract everywhere several switch legs that were 14gauge while the rest of the circuit was 12gauge. Sounds like maybe your IBEW trainers need to get trained!
 
I went round and round with a contractor (not a licensed electrician, more of a "county" electrician) about this issue a few years ago. He was absolutely convinced I was wrong, and that a 14 awg "fixture wire" could be used from the wall switch to the outlet (fixture) in the ceiling on a 20amp circuit with 12 awg everywhere else.

I tried over and over to explain to him the difference between a switch leg and a fixture wire.

After 4 meetings on site with my NEC to show him the proper code section (yeah - he didn't own a code book) I finally had to resort to the "I'm the AHJ, and I will not approve this installation. Change it, or the project goes no further" One of the very few times I've had to play that card in 18 years as an inspector.
 
Darren Emery said:
I went round and round with a contractor (not a licensed electrician, more of a "county" electrician) about this issue a few years ago. He was absolutely convinced I was wrong, and that a 14 awg "fixture wire" could be used from the wall switch to the outlet (fixture) in the ceiling on a 20amp circuit with 12 awg everywhere else. I tried over and over to explain to him the difference between a switch leg and a fixture wire.

After 4 meetings on site with my NEC to show him the proper code section (yeah - he didn't own a code book) I finally had to resort to the "I'm the AHJ, and I will not approve this installation. Change it, or the project goes no further" One of the very few times I've had to play that card in 18 years as an inspector.
Click to expand...
And no doubt he is another contractor telling the story about how the code official said "Im the AHJ and Because I said so"
 
jar546 said:
And no doubt he is another contractor telling the story about how the code official said "Im the AHJ and Because I said so"
Click to expand...
Very likely. One reason I am so reticent to drop the hammer - I do my absolute best to explain the code, explain the reasoning behind the code, and to come to an understanding with contractors. I've worked in the same city for 18 years, and developed a pretty good relationship with 99.8% of the industry.

Can't win 'em all, I guess.
 
For lighting I'd allow 14 awg tap from 12 awg but I'll count the fixtures and in the same room.

Also for recepticle outlets useing 12awg for 15A recepticles instead of one in one out would anyone OK to use 14awg pig tail?
 
Span said:
For lighting I'd allow 14 awg tap from 12 awg but I'll count the fixtures and in the same room.Also for recepticle outlets useing 12awg for 15A recepticles instead of one in one out would anyone OK to use 14awg pig tail?
Click to expand...
Span - just curious - what code section would you cite for this allowance?
 
Span said:
For lighting I'd allow 14 awg tap from 12 awg but I'll count the fixtures and in the same room.Also for recepticle outlets useing 12awg for 15A recepticles instead of one in one out would anyone OK to use 14awg pig tail?
Click to expand...
Sorry but you are in violation of the nec allowing this install.
 
Dennis said:
Sorry but you are in violation of the nec allowing this install.
Click to expand...
Agreed, no brainer. If anyone needs more ammo against the install in question, take a look at NEC T250.122. Hows that 14AWG EGC look now? (If we are looking at cable assemblies)
 
Are you permitted, once in the fixture, to wire between fixtures with 14? Say you have 8 recessed cans in the kitchen, 12 to the first can, then 14 in between the cans?

Brent.
 
MASSDRIVER said:
Are you permitted, once in the fixture, to wire between fixtures with 14? Say you have 8 recessed cans in the kitchen, 12 to the first can, then 14 in between the cans?Brent.
Click to expand...
No, that's not permitted either! Unless, it was on a 15 amp breaker. Then it would comply with the code but many of us would still not agreed to it being best practice.
 
The wire in the fixture that usually is part of the fixture can be reduced. You cannot wire between fixtures with a reduce conductor size.
 
jar546 said:
Is it legal to use a 14awg wire in a basement for a lighting switch leg if the basement is on a dedicated 20A circuit and the rest of the wiring is 12awg?Table 210.24 appears to support this?



Hmmmmmmm
Click to expand...
Is this an actual tap?
 
MASSDRIVER said:
To be simplistic, the breaker determines the wire size?Brent.
Click to expand...
yes, that is very simplistic because there are tap rules that exist for specific situations where breaker size does not always equal wire size. There are other rules that also allow breaker size to exceed wire rating size but in this case, the switch leg talked about is not in the tap rules.
 
A tap usually refers to a downsize in wire size so I am not sure why it would not be a tap. Art. 240.21(B) taps are for feeders and art. 240.21(A) -taps for branch circuits- takes us to 210.19 and 210.20
 
Dennis said:
A tap usually refers to a downsize in wire size so I am not sure why it would not be a tap. Art. 240.21(B) taps are for feeders and art. 240.21(A) -taps for branch circuits- takes us to 210.19 and 210.20
Click to expand...
The tap rule requires the distant end of the tap to have a disconnecting means (breaker or fuse) that is consistent with the ampacity rating of the tap to ensure that the tap does not exceed its designed current carrying capability. A short circuit of this tap between the tap and the “downstream” breaker would not be specifically protected for other than upstream relay protection settings like ground fault, instantaneous, or other protection settings…
 
  • Like
Reactions: ICE
You must log in or register to reply here.
Top