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[GMCnet] house electrical [message #340946] Tue, 12 February 2019 16:29 Go to next message
gmc-email-list is currently offline  gmc-email-list   United States
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Registered: February 2019
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My batteries are shorted and the batteries discharged. The trouble seems
to be the main wire that runs from the rear house batteries to the front
engine batteries. It is original ( 43 years old ) and is missing some of
the insulation.
Where does the wire go and is it easily replaced? What size is the wire?
Fred Estabrook
76 Ell
Florence AZ
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Re: [GMCnet] house electrical [message #340948 is a reply to message #340946] Tue, 12 February 2019 16:48 Go to previous messageGo to next message
gmc-email-list is currently offline  gmc-email-list   United States
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It is a 1 gauge wire. It runs from the area near the rear battery inside the driver’s side wall to the front and then down along the front frame across to the area of the front battery.

The insulation eventually goes bad and flakes off. It will be quite a job getting it out of the sidewall. You’d have to take the paneling off the wall and then it might be embedded into the foam insulation. It might be easier to run another wire under the motorhome along the inside of the frame. Some have put the wire inside a length of garden hose to give more protection.

Emery Stora
77 Kingsley
Frederick, CO

> On Feb 12, 2019, at 3:29 PM, Kathy and Fred Estabrook via Gmclist wrote:
>
> My batteries are shorted and the batteries discharged. The trouble seems
> to be the main wire that runs from the rear house batteries to the front
> engine batteries. It is original ( 43 years old ) and is missing some of
> the insulation.
> Where does the wire go and is it easily replaced? What size is the wire?
> Fred Estabrook
> 76 Ell
> Florence AZ
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org


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Re: [GMCnet] house electrical [message #340951 is a reply to message #340948] Tue, 12 February 2019 17:43 Go to previous messageGo to next message
gmc-email-list is currently offline  gmc-email-list   United States
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Registered: February 2019
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I use the semi rigid plastic hose that I get with the Vi-Aire compressors.
It easily will allow a cable between 3/8" and less than 1/2" in diameter.
It is slick and smooth inside, and a very tough plastic. I don't try to
retrieve that 40 year old wire. Cut it off on each end, and tag it with a
label indicating that it is unservicable. Wrap the ends with heat shrink
and seal them up.
Run the new conductor inside the frame channel and secure it with insulated
clamps. Should last longer than both of us.
Jim Hupy

On Tue, Feb 12, 2019, 2:49 PM Emery Stora via Gmclist <
gmclist@list.gmcnet.org wrote:

> It is a 1 gauge wire. It runs from the area near the rear battery inside
> the driver’s side wall to the front and then down along the front frame
> across to the area of the front battery.
>
> The insulation eventually goes bad and flakes off. It will be quite a job
> getting it out of the sidewall. You’d have to take the paneling off the
> wall and then it might be embedded into the foam insulation. It might be
> easier to run another wire under the motorhome along the inside of the
> frame. Some have put the wire inside a length of garden hose to give more
> protection.
>
> Emery Stora
> 77 Kingsley
> Frederick, CO
>
>> On Feb 12, 2019, at 3:29 PM, Kathy and Fred Estabrook via Gmclist gmclist@list.gmcnet.org> wrote:
>>
>> My batteries are shorted and the batteries discharged. The trouble
> seems
>> to be the main wire that runs from the rear house batteries to the front
>> engine batteries. It is original ( 43 years old ) and is missing some of
>> the insulation.
>> Where does the wire go and is it easily replaced? What size is the wire?
>> Fred Estabrook
>> 76 Ell
>> Florence AZ
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
> _______________________________________________
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Re: [GMCnet] house electrical [message #340952 is a reply to message #340946] Tue, 12 February 2019 19:33 Go to previous messageGo to next message
Tilerpep is currently offline  Tilerpep   United States
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Registered: June 2013
Location: Raleigh, NC
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I suggest you find the actual short if possible - especially if it is in the exposed section of heavy wire where it exits outside near the driver's foot well and crosses over to the engine battery on passenger side. There was a service bulletin in 1977 for this section. You can sheath that part fairly easy if the wire itself is still in good shape.

Also worth looking for is a lug mounted to the interior wall (aluminum structure) behind the electrical closet section in a typical GMC upfit wet bath (electric on driver's side across from the bath). The closet/panel's back wall may obstruct your view, but the lug is a connector between that #1 wire going back and another going forward which may or may not give you a logical place to replace to or from if the other sections are still good. If I pull out my driver side lower bunk and the wall covering, I would be able to run a new wire from the lug forward, fishing behind the cabinets for a few feet.

Backing up a step, I would be curious if both batteries are dead and what leads you to think it's the cable.


1975 Glenbrook, 1978 Royale rear bath Raleigh, NC
Re: [GMCnet] house electrical [message #340954 is a reply to message #340952] Tue, 12 February 2019 21:06 Go to previous messageGo to next message
gmc-email-list is currently offline  gmc-email-list   United States
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What Jim and Gene said. Pull anew wire and put it inside a conduit of any
kind to prevent chafing.
If you are able to visually inspect the wire and you see an obvious failure
from abrasion or poor routing , fine attend to that issue and see if you
win. If you inspect the wire and observe casing failure for no reason then
you must assume the whole wire is bad.

Sully
Bellevue wa

On Tue, Feb 12, 2019 at 5:42 PM Tyler via Gmclist
wrote:

> I suggest you find the actual short if possible - especially if it is in
> the exposed section of heavy wire where it exits outside near the driver's
> foot well and crosses over to the engine battery on passenger side. There
> was a service bulletin in 1977 for this section. You can sheath that part
> fairly easy if the wire itself is still in good shape.
>
> Also worth looking for is a lug mounted to the interior wall (aluminum
> structure) behind the electrical closet section in a typical GMC upfit wet
> bath
> (electric on driver's side across from the bath). The closet/panel's back
> wall may obstruct your view, but the lug is a connector between that #1 wire
> going back and another going forward which may or may not give you a
> logical place to replace to or from if the other sections are still good.
> If I
> pull out my driver side lower bunk and the wall covering, I would be able
> to run a new wire from the lug forward, fishing behind the cabinets for a
> few feet.
>
> Backing up a step, I would be curious if both batteries are dead and what
> leads you to think it's the cable.
> --
> 1975 Glenbrook, 1978 Royale rear bath
> Raleigh, NC
>
> _______________________________________________
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Re: [GMCnet] house electrical [message #340955 is a reply to message #340952] Tue, 12 February 2019 21:12 Go to previous messageGo to next message
gmc-email-list is currently offline  gmc-email-list   United States
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On Feb 12, 2019, at 8:33 PM, Tyler via Gmclist wrote:

> I suggest you find the actual short if possible - especially if it is in the exposed section of heavy wire where it exits outside near the driver’s foot well and crosses over to the engine battery on passenger side.

I agree with Tyler but would go a step further. If you suspect ANY problem AT ALL with that front-to-back tie cable then ABANDON it as others have suggested.

Here’s why I say that: the tie cable runs through several of the vertical aluminum ribs in the coach body on its way from the back to the front. I have done interior restorations on two GMCs and in both cases I’ve found said cable routed through holes in those metal ribs with razor sharp burrs around the drill holes. Couple that with the fact that the uber-flammable spray-in foam is in very close or intimate proximity to both the cable and those razor sharp burrs - and the tremendous short-circuit current that could be delivered by a battery via that cable - and you have a fire waiting to happen.

During my restorations I also found that the 120V Romex/NM wiring to air conditioners and other loads went through similarly scary transitions in the aluminum body. I did not replace the romex but I did take slit rubber hose and push it through each of the transitions to prevent chafing of the wire against the burrs on the drilled holes in the ribs.

—Jim

Jim Miller
1977 Eleganza
1977 Royale
Hamilton, OH




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Re: [GMCnet] house electrical [message #340963 is a reply to message #340946] Wed, 13 February 2019 06:37 Go to previous messageGo to next message
Tilerpep is currently offline  Tilerpep   United States
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Registered: June 2013
Location: Raleigh, NC
Karma: 7
Senior Member
If I'm remembering correctly, you will have to rewire the house feed if you abandon the long length wire completely - that's why I was thinking of the lug behind the closet. If you don't undo that lug to eliminate any and all bad wires, you will have a hot source down the wall still from the battery and/or the charger, correct?

Here are some pics, not mine, for reference:

This one shows general location, lug hard to see in back out of focus
http://www.gmcmhphotos.com/photos/data/6410/medium/2013-07-06_201406.jpg

This one shows lugs with both hot and ground
http://www.gmcmhphotos.com/photos/data/6410/medium/2013-07-06_201438.jpg

To clarify the pics, there is an isolated positive terminal from GMC, and the picture shows an extra ground added next to it.



1975 Glenbrook, 1978 Royale rear bath Raleigh, NC
Re: [GMCnet] house electrical [message #340966 is a reply to message #340946] Wed, 13 February 2019 09:33 Go to previous messageGo to next message
Ty Hardiman is currently offline  Ty Hardiman   United States
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Registered: April 2017
Location: Norman, Oklahoma
Karma: 0
Member
Good advice here, one point of clarification - the factory schematic shows a 1 gauge wire from the rear battery to the "living area battery pickup junction block", but then upsizing to a number 0 (a 1/0 or one-aught) wire from there to the front of the coach.

Norman, OK / August 1977 Kingsley / 403 / 3.55 / 16" / Quadrajet
Re: [GMCnet] house electrical - Little Gotcha [message #340975 is a reply to message #340966] Wed, 13 February 2019 13:01 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
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Senior Member
If you are doing electrical work on your coach, be aware that they are wired with SAE sized wire and NOT AWG. SAE wire sizes can be as much as 10% smaller than AWG and the voltage drop at high loads can be a real big issue.

Also, if you have to buy much wire, find a marine supplier (not a boat stuff store like West Marine). Marine wire has two significant advantages in addition to being AWG sizes:
It is finer stranded for both fatigue resistance and easier bending to fit.
It is all tinned strands for corrosion resistance.
The increase in cost is minimal and as I always made note to clients, you only have to buy it once.....

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
Re: [GMCnet] house electrical - Little Gotcha [message #340977 is a reply to message #340975] Wed, 13 February 2019 13:04 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
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Registered: March 2007
Location: S.E. Michigan
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Senior Member
Marine wire suppliers that I forgot to include:
http://www.genuinedealz.com/
https://www.delcity.net/
https://theelectricaldepot.com/

There you are.....

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
Re: [GMCnet] house electrical - Little Gotcha [message #340979 is a reply to message #340975] Wed, 13 February 2019 14:32 Go to previous messageGo to next message
gmc-email-list is currently offline  gmc-email-list   United States
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Thanks for the heads up info Matt. Will probably have to order on line as
there are not too many marine stores in AZ.

On Wed, Feb 13, 2019 at 12:26 PM Matt Colie via Gmclist <
gmclist@list.gmcnet.org> wrote:

> If you are doing electrical work on your coach, be aware that they are
> wired with SAE sized wire and NOT AWG. SAE wire sizes can be as much as 10%
> smaller than AWG and the voltage drop at high loads can be a real big
> issue.
>
> Also, if you have to buy much wire, find a marine supplier (not a boat
> stuff store like West Marine). Marine wire has two significant advantages
> in
> addition to being AWG sizes:
> It is finer stranded for both fatigue resistance and easier bending to fit.
> It is all tinned strands for corrosion resistance.
> The increase in cost is minimal and as I always made note to clients, you
> only have to buy it once.....
>
> Matt
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Electronically Controlled Quiet Engine Cooling Fan
> OE Rear Drum Brakes with Applied Control Arms
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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Re: [GMCnet] house electrical [message #341021 is a reply to message #340955] Thu, 14 February 2019 16:39 Go to previous messageGo to next message
gmc-email-list is currently offline  gmc-email-list   United States
Messages: 124
Registered: February 2019
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Senior Member
Heyco makes a complete line of various size snapin plastic bushings, that are designed to protect wires and hoses from chafe. McMaster Carr has the complete line.
> On February 12, 2019 at 7:12 PM Jim Miller via Gmclist wrote:
>
>
> On Feb 12, 2019, at 8:33 PM, Tyler via Gmclist wrote:
>
>> I suggest you find the actual short if possible - especially if it is in the exposed section of heavy wire where it exits outside near the driver’s foot well and crosses over to the engine battery on passenger side.
>
> I agree with Tyler but would go a step further. If you suspect ANY problem AT ALL with that front-to-back tie cable then ABANDON it as others have suggested.
>
> Here’s why I say that: the tie cable runs through several of the vertical aluminum ribs in the coach body on its way from the back to the front. I have done interior restorations on two GMCs and in both cases I’ve found said cable routed through holes in those metal ribs with razor sharp burrs around the drill holes. Couple that with the fact that the uber-flammable spray-in foam is in very close or intimate proximity to both the cable and those razor sharp burrs - and the tremendous short-circuit current that could be delivered by a battery via that cable - and you have a fire waiting to happen.
>
> During my restorations I also found that the 120V Romex/NM wiring to air conditioners and other loads went through similarly scary transitions in the aluminum body. I did not replace the romex but I did take slit rubber hose and push it through each of the transitions to prevent chafing of the wire against the burrs on the drilled holes in the ribs.
>
> —Jim
>
> Jim Miller
> 1977 Eleganza
> 1977 Royale
> Hamilton, OH
>
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

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Re: [GMCnet] house electrical [message #341135 is a reply to message #340946] Tue, 19 February 2019 12:38 Go to previous message
GatsbysCruise is currently offline  GatsbysCruise   United States
Messages: 261
Registered: January 2017
Location: Waukegan, Illinois
Karma: 3
Senior Member
Be certain the cable is bad. I had a battery short out and the system acted like a cable failure.

THE PO of my coach had torn the insides out so it is difficult to guess what was original.
Having said that, My positive lug is not attached to any structure, it sort of hangs there next to the AC breaker box.
All the pos connections connect to that.
The cable going forward go through the wall next to the couch and forward to the engine compartment.
If your cable has insulation coming off, it would be easier to just run a new cable from the originating
position in the engine compartment, run along the frame under the coach and enter to where ever your lug is
connected to. Putting it outside along the frame probably suggests its better to encase it in a hose or
some plastic type tube to protect it. I imagine you will only change that cable out once in your lifetime
as they do hold up rather well.
To attemp to replace along the original path way could involve having to dismantle the kitchen cabinets (mine
runs behind them, then the wall behind the couch and the route in the engine compartment.

Was easy for them when nothing was in the coach, for us, a little more work.



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