Bob,
Am I drawing the correct conclusion from your comments that using split loom
or most any "conduit" is NOT a preferred method of "protecting" a wire
bundle in the engine compartment?
I must admit that in my planning and building I have "assumed" conduit was
desirable from an appearance standpoint while not considering the
temperature the wires would be exposed to.
Allen Fulmer
RV7 Eggenfellner Subaru E6Ti
>>>-----Original Message-----
>>>From: owner-aeroelectric-list-server@matronics.com
>>>[mailto:owner-aeroelectric-list-server@matronics.com]On
>>>Behalf Of Robert L. Nuckolls, III
>>>Sent: Sunday, October 05, 2008 9:52 AM
>>>To: aeroelectric-list@matronics.com
>>>Subject: Re: Split loom melting
>>>
>>>
>>>Nuckolls, III" <nuckolls.bob@cox.net>
>>>
>>>At 09:07 AM 10/5/2008 -0400, you wrote:
>>>>Caldwell" <lrsecaldwell@earthlink.net>
>>>>
>>>>I have experanced melting of some of the black split loom I used an
>>>>conduit to prevent wire chaffing in my engine compartment.
>>> One piese
>>>>that melted was 6 or 7 inches from the exhaust tube.
>>>>
>>>>Note that this is a recent problem that has occured after I
>>>add some
>>>>additional heat shield due to heat discoloration on the
>>>inside of the
>>>>lower cowl,
>>>>
>>>>Has anyone else had this problem?
>>>>
>>>>Does anyone have any data on what temperatue exists in the
>>>engine compartment?
>>>
>>> Temperatures under the cowl can range from ambient
>>> (OAT at xx-thousands of feet in the winter) to
>>> hundreds of degrees (radiant heating from exhaust
>>> components). In the "big airplane factories" we've
>>> had suppliers of spiral wrap, split loom and zippered
>>> sleeve wire bundling products come and go. The
>>> added cost, labor, maintenance and addition to weight
>>> have never passed muster with the guys who tracked
>>> cost-of-ownership for airplanes.
>>>
>>> You can bet that should this technology be considered
>>> worthy of flight in a TC aircraft, it would be made
>>> from materials similar to the wire it protects . . . i.e.
>>> Tefzel or one of the more exotic synthetics. Given
>>> that Tefzel tie wraps are around $1.50 each in low
>>> quantities, you can bet that the cost of Tefzel spiral
>>> wrap is similarly breathtaking.
>>>
>>>>As an aside I did some informal tests of the black split
>>>loom and it burns
>>>>and is not self extinguishing.
>>>>Are thre any good fire resistant alternatives?
>>>
>>> Not aware of any. The popular nylons are probably
>>> incapable of tolerating the localized heating situation
>>> you've identified. You might consider re-routing the
>>> bundle, running it through fire-sleeve, or some other
>>> process that puts a barrier between your wire bundle
>>> and the IR heat source that's pushing it over the
>>> cliff. I'd vote for re-routing the wire bundle.
>>>
>>>
>>> Bob . . .
>>>
>>>
>>> ----------------------------------------)
>>> ( . . . a long habit of not thinking )
>>> ( a thing wrong, gives it a superficial )
>>> ( appearance of being right . . . )
>>> ( )
>>> ( -Thomas Paine 1776- )
>>> ----------------------------------------
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>Checked by AVG - http://www.avg.com
>>>Date: 10/5/2008 9:20 AM
>>>
