| [GMCnet] 12V wire to house battery [message #170930] |
Sat, 26 May 2012 22:47  |
Rick
Messages: 36
Registered: September 2010
Location: Ft. Worth
Karma: 0
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I'm new to GMC's and I'm very grateful for this list.
A short while back I read a posting about the 12V wire from the house battery up front to the charger/distribution center shorting to the frame in the wall and causing a fire.
So while replacing/rewiring my distribution center I paid close attention to that wire and found signs of excess heat on the coating. Decided to move up my remodeling/upgrading schedule and removed all the wall panels from the closet (mid coach) to the front dash and found the wire in real bad shape (see photos).
http://www.gmcmhphotos.com/photos/g6086-wire-to-house-battery.html
The wire should signs of melting on about half of the total length and bare wires were showing at 2 or 3 places. Needless to say I'm replacing it with a heavy duty 4 gauge cable.
Rick Drummond
Prior Lake MN
1974 re-Painted Desert
TZE064V100077
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Rick Does Ft. Worth Tx
1976 Glenbrook "Some Assembly Required"
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| Re: [GMCnet] 12V wire to house battery [message #170934 is a reply to message #170930] |
Sun, 27 May 2012 02:06  |
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mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
Karma: 0
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| Rick wrote on Sat, 26 May 2012 20:47 |
I'm new to GMC's and I'm very grateful for this list.
A short while back I read a posting about the 12V wire from the house battery up front to the charger/distribution center shorting to the frame in the wall and causing a fire.
So while replacing/rewiring my distribution center I paid close attention to that wire and found signs of excess heat on the coating. Decided to move up my remodeling/upgrading schedule and removed all the wall panels from the closet (mid coach) to the front dash and found the wire in real bad shape (see photos).
http://www.gmcmhphotos.com/photos/g6086-wire-to-house-battery.html
The wire should signs of melting on about half of the total length and bare wires were showing at 2 or 3 places. Needless to say I'm replacing it with a heavy duty 4 gauge cable.
Rick Drummond
Prior Lake MN
1974 re-Painted Desert
TZE064V100077
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Rick Does Ft. Worth Tx 1976 Glenbrook "Some Assembly Required"
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Rick,
I am VERY glad you looked at your wiring. It looks like it could have been a BAD issue.
I see two different coaches listed for you. (Looks like two different signature lines.) What coach are you talking about?
The reason I ask is the wiring is considerably different between the two coaches listed.
The wiring problem that caused the fires was the large (0 gauge in the 1975 diagram) red cable added with the 1975 relocation of the house batteries.
It LOOKS like the wire in the picture was the 10 gauge red wire of the earlier coaches... I am fairly sure (but not certain) that the earlier coached did NOT have a published problem with this wire.
In any case, I would wonder how enough current to melt the wire made it on to this wire. Pulling up both diagrams I see that both types are protected by circuit breakers on the battery end. (50 amp on the early and 60 amp on the later.) But looking at the diagram, BOTH have charging current applied to the opposite end without a fuse/circuit breaker on the diagrams....
Never noticed THAT before. Makes me wonder...
My 1973 has fuses in the converter, so that end on my early coach is now protected. (Did the original buzz box have output fuses built in?)
I do not have a coach wired like the later GM coaches but, I do not see any protection for the charging current from the alternator on the 1975 diagram.... granted "0 gauge" wire can carry a lot of current and the alternator WAS limited to 80 amps.
Something looks odd here.
Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo'
http://m000035.blogspot.com
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| Re: [GMCnet] 12V wire to house battery [message #170937 is a reply to message #170934] |
Sun, 27 May 2012 03:59 |
Rick
Messages: 36
Registered: September 2010
Location: Ft. Worth
Karma: 0
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Mike,
Not sure where the phantom signature line came from?? My coach is the 1974 ex Painted Desert. Mine does have the 10 gauge wire with a 50A thermal breaker under the hood.
Sounds like I did not have the same issue as the '75 wiring that was posted (still REALLY glad I saw that post cause it made me look hard at that wire!).
The PO had done some scary looking wiring mods to the fuse block and power converter and said that the "charging" circuit of the power converter had burned up and didn't work which may be the reason for this wire melting. I would have thought the 50A thermal would have prevented it but I'm not sure how much current is needed to turn this type of wire into a 'heating coil'.
The old power converter is a 40A unit by "C-Sinc", not sure if that was the original or not.
(By the way, showing my new guy ignorance here: Is the "buzz box" a generic term for the power conditioner/charger? Or is it referring to a specific brand?)
Hence my project of replacing the power converter, fuse block, and related wiring.
I had already planned on adding a resettable circuit breaker to the power converter end of this wire. Now I'm going to string a whole new wire and I'm replacing the 50A thermal breaker under the hood. My plan is to use a 4 gauge wire protected by plastic wire wrap like before.
Regards,
Rick D
Rick Drummond
Prior Lake MN
1974 (re-)Painted Desert 26'
TZE064V100077
Photos: http://www.gmcmhphotos.com/photos/u18085-r-drummond.html
Email: RandTs.GMC@gmail.com
On May 27, 2012, at 2:06 AM, Mike Miller <m000035@gmail.com> wrote:
>
>
> Rick wrote on Sat, 26 May 2012 20:47
>> I'm new to GMC's and I'm very grateful for this list.
>> A short while back I read a posting about the 12V wire from the house battery up front to the charger/distribution center shorting to the frame in the wall and causing a fire.
>> So while replacing/rewiring my distribution center I paid close attention to that wire and found signs of excess heat on the coating. Decided to move up my remodeling/upgrading schedule and removed all the wall panels from the closet (mid coach) to the front dash and found the wire in real bad shape (see photos).
>> http://www.gmcmhphotos.com/photos/g6086-wire-to-house-battery.html
>> The wire should signs of melting on about half of the total length and bare wires were showing at 2 or 3 places. Needless to say I'm replacing it with a heavy duty 4 gauge cable.
>>
>>
>> Rick Drummond
>> Prior Lake MN
>> 1974 re-Painted Desert
>> TZE064V100077
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
>> Rick Does Ft. Worth Tx 1976 Glenbrook "Some Assembly Required"
>
>
> Rick,
>
> I am VERY glad you looked at your wiring. It looks like it could have been a BAD issue.
>
> I see two different coaches listed for you. (Looks like two different signature lines.) What coach are you talking about?
>
> The reason I ask is the wiring is considerably different between the two coaches listed.
>
> The wiring problem that caused the fires was the large (0 gauge in the 1975 diagram) red cable added with the 1975 relocation of the house batteries.
>
> It LOOKS like the wire in the picture was the 10 gauge red wire of the earlier coaches... I am fairly sure (but not certain) that the earlier coached did NOT have a published problem with this wire.
>
> In any case, I would wonder how enough current to melt the wire made it on to this wire. Pulling up both diagrams I see that both types are protected by circuit breakers on the battery end. (50 amp on the early and 60 amp on the later.) But looking at the diagram, BOTH have charging current applied to the opposite end without a fuse/circuit breaker on the diagrams....
>
> Never noticed THAT before. Makes me wonder...
>
> My 1973 has fuses in the converter, so that end on my early coach is now protected. (Did the original buzz box have output fuses built in?)
>
> I do not have a coach wired like the later GM coaches but, I do not see any protection for the charging current from the alternator on the 1975 diagram.... granted "0 gauge" wire can carry a lot of current and the alternator WAS limited to 80 amps.
>
> Something looks odd here.
> --
> Mike Miller -- Hillsboro, OR -- on the Black list
> (#1)'73 26' exPainted D. -- (#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
> http://m000035.blogspot.com
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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Rick Does Ft. Worth Tx
1976 Glenbrook "Some Assembly Required"
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| Re: [GMCnet] 12V wire to house battery [message #170944 is a reply to message #170930] |
Sun, 27 May 2012 08:07 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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The long heavy 0 ga failure is mainly a chafing issue, combined with aging insulation that is less flexible. Most redo with the high temp convoluted tubing over it. Wondering about your 4 Ga choice. If that's for the 10 Ga replacement you've upped the conductor but should have it breakered as you may. If it's for the 0 Ga that may not be enough to properly boost the 455 off of due to the long run. Anyway, good for you for checking and that will be a good improvemnt.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] 12V wire to house battery [message #170949 is a reply to message #170937] |
Sun, 27 May 2012 09:14 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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| Rick wrote on Sun, 27 May 2012 04:59 |
<snip>
The old power converter is a 40A unit by "C-Sinc", not sure if that was the original or not.
(By the way, showing my new guy ignorance here:
Is the "buzz box" a generic term for the power conditioner/charger? Or is it referring to a specific brand?)
<snip>
Regards,
Rick D
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Rick,
C-Sinc(C-Sine?), Sola and Constavolt were builders of Ferro-resonant power supplies. These devices used the 60Hz line frequency to control the output voltage. Because a large hunk of iron had to be resonating at that 60Hz, there is/was a constant buzz from the power supply that was very hard to hide. Hence, the universal label - Buzz Box - was applied to all.
In their day, they were the best that was available. That day is gone. I can't believe how good the new systems are.
When you take it out, don't toss it. They are a great 12V (14.X V) bench supply that can be used to test things.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] 12V wire to house battery [message #171077 is a reply to message #170937] |
Mon, 28 May 2012 11:32 |
Richard Denney
Messages: 920
Registered: April 2010
Karma: 9
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Senior Member |
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On Sunday, May 27, 2012, Rick wrote:
> Not sure where the phantom signature line came from?? My coach is the 1974
> ex Painted Desert. Mine does have the 10 gauge wire with a 50A thermal
> breaker under the hood.
>
>
One possible source of overheating is a screw in the wall that has
penetrated the insulation. That happened on my coach when a PO installed an
aftermarket dinette on that port-side wall. I didn't discover it until I
stripped that wall. Fortunately, it missed the copper by a hair.
I have a new thermal breaker on the front panel in place of the original.
The value doesn't matter as long as it is low enough not to overheat 10-Ga
wire. I used a 60 or 80-amp thermal breaker. This breaker is strictly to
prevent a catostrophic overheating if the insulation fails and the copper
finds a ground. On the converter end, I have a 40-amp magnetic breaker
(switchable) to protect my 40-amp Progressive Dynamics converter.
If your house battery is up front, you do not need a 4-ga wire-10 is plenty
and there is really high-quality stuff with nearly unmeltable insulation
made for marine use. And if you plan to move the house batteries to the
rear, 4-ga won't be big enough--you'll need something that can handle a
coupla hundred amps during start boost over a 30-foot length. I'd recommend
0-gauge. Unless you plan extended dry camping, though, my experience is
that a single battery up front is fine and saves a lot in modifications.
The factory provided a plastic convoluted conduit for the 10-ga wire in
early coaches. Some of it is probably buried in spray foam insulation.
Rick "the original Rick D, heh" Denney
--
'73 230 "Jaws"
Northern Virginia
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