Another Bird fire

[freewill2008]

Exellent comments Pete, but readers should be cautioned that fuses in high
amperage cables may not provide complete protection. Consider a 200 amp fuse
placed to protect a main DC supply cable. An insulation breach can start slowly
and generate a great deal of heat without popping the fuse. In areas where
engine heat, oil, and abrasion are present, the resistance of insulation can
break down and start generating heat long before there is a full metal-to-metal
short. By the time the breach gets bad enough to pop the 200 amp fuse enough
heat may have been generated to start a fire.

Fuses are very important, but vigilant inspection is a must for safety.

Bob Griesel '84 FC31 WLII WA


--- In WanderlodgeForum@yahoogroups.com, Pete Masterson wrote:
>
> I think it should be pretty obvious that all high-amperage, unfused
> battery cables ought to be checked carefully.
> That would include the house batteries -- in a '95 those are contained
> in the rear-most curb-side compartment and on a tray by the engine. In
> addition, there are 3 engine batteries above the 2 house batteries
> near the engine.
>
> The house batteries are wired to a general distribution panel on the
> curb side of the firewall. The engine batteries are wired to the
> engine -- but also have a connection to the house batteries (as you
> can tie them together with a switch on the dash).
>
> The Bakersfield fire _might_ have been caused by a short from the
> house batteries and/or the firewall distribution panel. (We await
> further word from the fire inspector and/or insurance adjuster.)
>
> Randy's fire was caused by a dead short in the front most, street side
> compartment, where the battery cable (running 40-some feet from the
> curb-side rear to the street side front-most compartment) that serves
> the generator starter motor. Apparently, from the report of the fire
> inspector and insurance adjuster, it appears that the insulation had
> been compromised where the heavy cable passed over a frame rail.
>
> We all may have been a little complacent over the 12v systems, since
> 12 v current rarely causes much of a fire or electrocution issue. It's
> easy to forget just how much potential amperage that the batteries can
> release in a dead short.
>
> The suggestion to install a high-amperage (slow acting) fuse on the
> batteries makes a lot of sense. A slow acting fuse is required since
> things like the engine and generator starter motor can draw a brief,
> very high amperage burst -- and you don't want to blow the fuse. But a
> short would cause a longer drain, and would blow the fuse.
>
> Of course, a careful inspection of all the high-amperage wires is
> called for. Unfortunately, wires may pass through areas where visible
> inspection is difficult or impossible. (Mirrors mounted to extension
> handles and flashlights would be quite useful.) Even so, it's likely
> that there are places where thorough inspection will prove impossible.
> (Which simply increases the importance of fusing the batteries.)
>
> Another 'wise' modification would be to install a high-amperage switch
> to completely isolate the batteries from the coach. Marine supplies
> sell such switches for boats and they can be adapted to motorhome use
> quite easily. The added advantage of such a switch would be to ensure
> that all phantom loads (which BBs have in abundance) would be cut off,
> allowing longer storage periods without a charger on the batteries.
>
> In the Bakersfield situation, it's hard to discern how the fire might
> have been avoided. The owner reported that he'd inspected the wires
> (as best as he could) after hearing about Randy's fire. It is unlikely
> that any of us would have shut off all the batteries while in a nearby
> restaurant for dinner -- but fuses _might_ have saved the coach, had
> they been installed. (Then, again, pending a final determination of
> the cause of the fire, it might not have been effective.)
>
> Pete Masterson
> (former) '95 Blue Bird Wanderlodge WBDA 42
> El Sobrante CA
> aeonix1@...
>
>
>
>
> On Nov 26, 2009, at 6:31 PM, Ernie Ekberg wrote:
>
> >
> >
> > Where I observed was the batteries on the curbside, close to the
> > firewall of the engine compartment
> >
> > Ernie Ekberg
> > 83PT40
> > Wanderlodge
> > Weatherford, Tx 817-475-3991
> > http://autos.groups.yahoo.com/group/erni...gandrepair
> >
> >
> > --- On Thu, 11/26/09, SteveQ wrote:
> >
> > From: SteveQ
> > Subject: [WanderlodgeForum] Re: Another Bird fire
> > To: WanderlodgeForum@yahoogroups.com
> > Date: Thursday, November 26, 2009, 8:27 PM
> >
> > Ron, Ernie
> >
> > Are you refering to the house batteries or the three engine
> > batteries when you say main battery bank? I looked at everything
> > after Randy's fire but will give it another CLOSER look when I get
> > back to Texas next month.
> >
> > Steve Quandt
> > 1993 PT-40
> > Cold in Iron Mountain, Mi
> > Coach enjoying warm weather in Marble Falls TX
> >
> > --- In WanderlodgeForum@ yahoogroups. com, "ronmarabito2002"
> > wrote:
> > >
> > >
> > > Sorry to hear of the loss of anyones coach. I warned the forum
> > after mine to check these cables and apparently it just went right
> > by everyone. What a shame. I sure hope everyone gets out there and
> > checks these cables now.
> > >
> > > R.E. (Ron) Marabito, Dallas, TX 92WB40
> > >
> > > --- In WanderlodgeForum@ yahoogroups. com, "Ernie E"
> > wrote:
> > > >
> > > > I am wondering, since there have been 3 fires with the 90s
> > coaches, that if the battery cables are being chaffed behind the
> > main battery bank. Since the coaches involved were 92, 94 and 95
> > models, those with coaches of this era might want to check the
> > routing of these cables.
> > > > This is too much of a coincidence and may have taken these many
> > years to wear thru.
> > > > Fortunately, nobody in all 3 coaches were hurt.
> > > > Ernie- 83PT40 in New River, Az
> > > >
> > >
> >
> >
> >
> >
>