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#99959 - 09/28/06 09:02 AM branch circuit taps  
earlydean  Offline
Joined: Dec 2003
Posts: 751
Griswold, CT, USA
We all know we cannot connect our 15 amp receptacles by using copper #14 taps from a 20 amp branch circuit because of 210.19(A)(4) exc.1(c), which specifically disallows such taps.

But, take a look at exc.1(a). Is it just me, or does the wording of this exception allow a #14 tap on up to a 40 amp circuit to feed a luminaire, so long as the taps doesn't extend beyond 18 inches past the light? I know this is not true (I checked with NFPA) but, the wording is strange:

"(a) Individual lampholders or luminaires (fixtures) with taps extending not longer than 450 mm (18 in.) beyond any portion of the lampholder or luminaire (fixture)."

The actual meaning per NFPA is taps are allowed up to 18 inches long to feed individual light fixtures.


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#99960 - 09/28/06 09:14 AM Re: branch circuit taps  
SteveFehr  Offline
Joined: Mar 2005
Posts: 1,213
Chesapeake, VA
Looks like it! This is probably related to tap size issues- a lot of connecters and clamps are sized for #14 or #12 and you have to splice on a pigtail with the smaller wire.

I can see why they'd still specifically disallow this method for receptacles, though.

[This message has been edited by SteveFehr (edited 09-28-2006).]

#99961 - 09/28/06 11:15 AM Re: branch circuit taps  
gfretwell  Offline

Joined: Jul 2004
Posts: 9,140
It is a lot easier to control the load in a lamp holder. Once you let the user start plugging things in you are at the mercy of the OCPD.
Now if they would just put an OCPD in those "edison base to receptacle" adapters, or ban them outright...
I have seen them in the bathroom luminaire (18ga tap) with a hair dryer plugged in.

Greg Fretwell

#99962 - 09/28/06 12:14 PM Re: branch circuit taps  
resqcapt19  Offline
Joined: Nov 2000
Posts: 2,148
Look at Exception #2 to 210.19(A)(4). If you use fixture wire you can run 50' of #18 on a 20A OCPD.


#99963 - 09/29/06 12:04 AM Re: branch circuit taps  
Steve T  Offline
Joined: Feb 2001
Posts: 306
Oak Park, IL, USA
This would be an application for long runs to decrease voltage drop.

Run #8's from a 50 amp CB, then tap off with #12's to the individual lights.

Big department stores come to mind.

#99964 - 09/29/06 04:16 AM Re: branch circuit taps  
iwire  Offline
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
Generally for lighting circuits if you ran 8 AWG strictly for voltage drop reasons it would not be on a 50 amp breaker, it would be on a 20 amp breaker.

If 8 AWG supplied by a 50 amp OCPD was specified it is because they want to load the circuit heavy with fixtures. This of course would be counter productive as far as voltage drop and of course a single circuit failure will darken a large area.

[This message has been edited by iwire (edited 09-29-2006).]

Bob Badger
Construction & Maintenance Electrician

#99965 - 09/29/06 07:24 AM Re: branch circuit taps  
earlydean  Offline
Joined: Dec 2003
Posts: 751
Griswold, CT, USA
Branch circuit taps are allowed the same as fixtures are allowed to have small wires. Did anyone ever stop to think about OC protection of those #18 wires going into the ballast? The overcurrent protection is only provided by the inherent high impedance of the ballast itself. Or, by setting a limit on the wattage and number of lamps. Same thing in a fixture stem or pendant fixture (covered by exc. 2).

I could never figure out the rational, however, for not allowing #14 taps for 15 amp receptacles. Is it simply because the receptacle is duplex, and two 10 amp loads could possibly be connected? If so, then a single 15 amp receptacle should be allowed to be connected with #14 wire, and it's not.


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