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#97098 01/22/06 08:20 AM
Joined: Jul 2001
Posts: 311
F
Member
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
Joined: Apr 2004
Posts: 28
B
Member
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
Joined: Jan 2001
Posts: 1,044
Tom Offline
Member
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
Joined: Apr 2004
Posts: 28
B
Member
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
Joined: Dec 2003
Posts: 751
E
Member
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
Joined: Jul 2001
Posts: 311
F
Member
earlydean

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

#97104 01/22/06 05:38 PM
Joined: Jan 2005
Posts: 5,445
Likes: 2
Cat Servant
Member
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
Joined: Jan 2003
Posts: 4,391
I
Moderator
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
Joined: Jan 2004
Posts: 1,507
G
Member
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
Joined: Jan 2005
Posts: 5,445
Likes: 2
Cat Servant
Member
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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