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#90791 12/11/04 10:25 AM
Joined: Dec 2000
Posts: 4,294
Member
I come across panels all the time that have wires cable tied together forming bundles in the wiring troughs. It makes for a neat looking job. As I understand it, over 24" of bundling requires derating,
I cut the cable ties when I see this, and the wires remain right where they were usually. In reality, I have accomplished nothing.

What's your take on this??

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#90792 12/11/04 10:45 AM
Joined: Jan 2001
Posts: 1,044
Tom Offline
Member
I don't recall ever seeing heat damaged insulation under these conditions, either in a wireway or panel enclosure. Of course, one man's experiance is a very limited database.

I could see where this might be a problem with conductors that are loaded on a continuous basis. I feel there are two factors that prevent damage most of the time, the first being are loads that are not continuous in nature. the second is that many conductors are already oversized based the actual load and requirements of limiting small conductors per 240.4(D) to a value lower than their actual ampacity.

Tom


Few things are harder to put up with than the annoyance of a good example.
#90793 12/11/04 11:03 AM
Joined: Jan 2003
Posts: 4,391
I
Moderator
IMO if the conductors are bundled longer than 24" it is a violation. [Linked Image]

I have never seen any damage from bundling but was that the question? [Linked Image]


Bob Badger
Construction & Maintenance Electrician
Massachusetts
#90794 12/12/04 02:15 PM
Joined: May 2003
Posts: 2,876
E
e57 Offline
Member
I have seen heat damage once in a bundle, but the case was extreme.

3' of bundle in 42 circuit panel (All of the circuits), 2' bundled in 2" EMT, another 2'+ bundled in a gutter, essentially 5-6' of the same conductors tightly bundled. They were pretty warm, and all the whites had yellowed, and insulation crispy long before thier time. They must of thought it looked real nice when they closed it up.

So yeah, I too don't like bundling in the panel, and consider it part of the 24" if it is done. I always bundle grounds and neutrals (24"), but leave the hots free. And will often cut the hots loose when I see it done by someone else.


[This message has been edited by e57 (edited 12-12-2004).]


Mark Heller
"Well - I oughta....." -Jackie Gleason
#90795 12/12/04 02:52 PM
Joined: May 2002
Posts: 1,716
R
Member
In any given panel, bundling is happening simply do to the close proximity of the conductors with or without wire ties isn't it?

Mark,
Quote
I always bundle grounds and neutrals, but leave the hots free.
in some cases, where these neutrals are not neutrals but just grounded conductors of two wire circuits, bundling could be an issue.

Roger

#90796 12/12/04 03:04 PM
Joined: May 2003
Posts: 2,876
E
e57 Offline
Member
Yeah Roger, Fully aware that neutrals can be current carrying, and only bundle 24" in the panel only for them. Thanks for pointing that out though. Believe it or not, I think panel manufactures have figured that out too, as it is often hard to bundle neautrals more than 24" with the bars on both sides in most panels these days. (Although you could if you tried)
-----------------------------------
As far as close proximity.... It's a grey area I would guess, because all of the conductors are in close proximity, if you look at that way. What kind of spacing should be maintaind, and how would you maintain it? (Im imaging some sort of device that would look like a comb to hold all the conductors from eachother...) But a far cry from being zip tied every few inches forming tight bundles where the conductors are held tight against eachother.

[This message has been edited by e57 (edited 12-12-2004).]


Mark Heller
"Well - I oughta....." -Jackie Gleason
#90797 12/12/04 05:45 PM
Joined: Jul 2002
Posts: 680
W
Member
I hate it when wires are wire tied together. When the cover is on a panel or trough, who is it impressing?? Makes it a pain in the butt to trace out a circuit. I'm in alot of places where I'm not familar with the installation. I sometimes have to trace out a lot of control wiring and having them bundled so I can't pull one to see where it moves sucks.

#90798 12/12/04 09:19 PM
Joined: Mar 2001
Posts: 2,056
R
Member
What about bundling 10-40' of NM cables.
I see residential homeruns bundled all the time and don't understand why the installation passes.

#90799 12/13/04 02:13 PM
Joined: Apr 2002
Posts: 178
R
Member
Hey Redsy you gotta start buying more donuts for the inspector.I see lots of things go under the bridge. Like you it never goes under my bridge but I try to comply always unless I miss something by accident.The donut keeps their writing hand ocupied.Please don`t bash me guys I`m kidding.

#90800 12/13/04 07:01 PM
Joined: Jan 2004
Posts: 1,507
G
Member
Hey Redsy- Bagels and creme cheese works too. Keeps both hands busy and I can't think and eat at the same time. [Linked Image]


George Little

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