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#97098 - 01/22/06 08:20 AM Tap Rule - 10'  
Frank Cinker  Offline
Member
Joined: Jul 2001
Posts: 311
Pennsylvania
http://www.geocities.com/cinkerf/misc3
In an industrial setting a light fixture is needed at the top of wood pole that service equipment is installed on. The photo link shows a 100 amp service (protected with 100 amp knife fuses in the disconnect). I see nothing wrong with using the 10' tap rule to supply a 20 Amp disconnect to provide power for a new light fixture located at the top of the pole. *The wiring space in the service disconnect enclosure is adequate *. Split bolt connectors will be used to tap the 12 AWG conductors to the 3AWG conductors. I believe this installation would be considered Code compliant. Please give me your opinion.

* Enclosures for Switches or Overcurrent Devices.
Enclosures for switches or overcurrent devices shall not be used as junction boxes, auxiliary gutters, or raceways for conductors feeding through or tapping off to other switches or overcurrent devices, unless adequate space for this purpose is provided. The conductors shall not fill the wiring space at any cross section to more than 40 percent of the cross-sectional area of the space, and the conductors, splices, and taps shall not fill the wiring space at any cross section to more than 75 percent of the cross-sectional area of that space.


[This message has been edited by Frank Cinker (edited 01-22-2006).]


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#97099 - 01/22/06 08:39 AM Re: Tap Rule - 10'  
BOSSMAN  Offline
Member
Joined: Apr 2004
Posts: 28
BEMIDJI, MN,USA
Why not get a lug kit for the meter and come off that.Im sure thay make one. & Its probly cost/labor effective.

John.


#97100 - 01/22/06 11:14 AM Re: Tap Rule - 10'  
Tom  Offline
Member
Joined: Jan 2001
Posts: 1,044
Shinnston, WV USA
Frank,

Looks OK to me, too, but based on what is usually done here in the Mountain State, it looks like overkill. [Linked Image] [Linked Image] [Linked Image]I usually see a mobile home service on a pole with a piece of #12 stuck into the load side of a 200 amp breaker feeding a 175watt dusk to dawn fixture without any breaker or fuse for protection of the smaller conductor.


Few things are harder to put up with than the annoyance of a good example.

#97101 - 01/22/06 11:42 AM Re: Tap Rule - 10'  
BOSSMAN  Offline
Member
Joined: Apr 2004
Posts: 28
BEMIDJI, MN,USA
Tom, thats why you cant just have a disconnect for a moble home service any more you must have some breaker spots.

John


#97102 - 01/22/06 03:45 PM Re: Tap Rule - 10'  
earlydean  Offline
Member
Joined: Dec 2003
Posts: 751
Griswold, CT, USA
Looks like your tap will exceed 10 feet in length (from the picture). If so, you will need OC protection at the disconnect.

Also, the split bolts may not be rated to connect #3 and #12. As I recall they go from #8 to #2.

"Madison Equipment UL listed for copper conductors only Silicone bronze construction Size/ min/max range of equal main / tap Color: DESC:Solid Size: SIZE:8/4 Mfg Part Nr: SB-4"

You could run #8 from the split bolt to the fused disconnect (or CB enclosure), then #12 from that point on.


Earl

#97103 - 01/22/06 04:56 PM Re: Tap Rule - 10'  
Frank Cinker  Offline
Member
Joined: Jul 2001
Posts: 311
Pennsylvania
earlydean

I was thought an overcurrent protective device was required even if 10' or less.


#97104 - 01/22/06 05:38 PM Re: Tap Rule - 10'  
renosteinke  Offline
Cat Servant
Member
Joined: Jan 2005
Posts: 5,316
Blue Collar Country
We want to look at 240.21 for this question.

As I read it, you can use the "10 ft" tap rules only within the same panel or gear. Your light would not qualify.

The 25 ft. rule lets you go outside the enclosure....but your wires have to have at least a third of the ampacity of the feeders. Since you're using #3, I assume the supply is 100 amps. This is one of those rare times you can use the full 35 amps #10 is rated for- so run #10 to your 20 amp fuses at the fixture.


#97105 - 01/22/06 05:55 PM Re: Tap Rule - 10'  
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
If he is tapping the supply side of the big switch it is not covered at all by 240.

Any conductors on the line side of the big switch are service conductors not feeders.


Bob Badger
Construction & Maintenance Electrician
Massachusetts

#97106 - 01/22/06 07:10 PM Re: Tap Rule - 10'  
George Little  Offline
Member
Joined: Jan 2004
Posts: 1,489
Michigan USA
Reneo- I don't know if I understand your statment.
Quote
As I read it, you can use the "10 ft" tap rules only within the same panel or gear. Your light would not qualify.

You can tap a feeder and exit the taped area via a raceway and go 10' feet. You can't exit the second panel and continue the tap. If they are Service conductors, there is no length limitation.

[This message has been edited by George Little (edited 01-22-2006).]


George Little

#97107 - 01/22/06 08:47 PM Re: Tap Rule - 10'  
renosteinke  Offline
Cat Servant
Member
Joined: Jan 2005
Posts: 5,316
Blue Collar Country
OOPS!

George, I have to give you credit for catching me in a goof!

I will put some of the blame on the wording of the code itself. 240.21(B)(1) starts off by saying "and the tap conductors comply with ALL of the following...."
Condition (2) says "conductors do not extend beyond the switchboard.." This is where I stopped reading.
Which is a pity, as condition (3) says "the conductors are enclosed in a raceway..."

Kind of hard to enter a raceway without exiting the switcjboard, if you ask me! Yet, the code does say "ALL!" Poor grammar, I expect, and I agree with your interpretation.


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