The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - 55.2-59 Bus Bar -Electrical--Clean and Efficient

dsraven · 11-13-2020, 05:22 PM

recently I rewired a burnt motorhome dash where the previous owner did a bit of wiring that caused the fire. there were many circuits taken off an inadequately supplied bus bar and when too many things were turned on the heat caused the insulation on the inadequately gauged, unfused supply wire to melt off, short to ground and start the fire. I used an under dash, insulated, color coded, terminal stud, supplied with battery positive through appropriately sized cable, and connected to a mega fuse under the hood near the battery that would interrupt the supply very close to the source should a problem ever occur.
I have worked on a lot of highway trucks in years past and found that some had the same wire color through out. if the insulating loom were peeled back far enough the wires were actually labelled on each wire as to what the circuits were. sounded good in theory but in actual practice it was a pain to work on. unlike the factory floor there are a lot of things added to the vehicle after the wiring is placed and covered up. I spent lots of time upside down in a cab with my head stuck in the console peeling back old black tape from the loom so I could trace wires back to a problem somewhere.

suggestions: check the max load on any given circuit (like if everything was running at max at the same time). before you build the circuit. leave some room for safety as far a wire gauge goes. fuse the supply wire at the source. fuse the circuit wires at THEIR source (like the fuse box or bus bar). use quality crimping tools and connectors. use double wall shrink tube on connections. double wall shrink tube has the insulating sheath on the outside but also has "hot glue" on the inside that melts when the tubing is shrunk around the connector so the tube doesn't move around on the wire later plus the glue adds a bit more insulating factor to the connection by taking up space between the wire strands and the tube outer surface. label the circuits. run the wire through a loom to protect against mechanical damage. tie the loom up periodically to protect against the harness sagging under it's own weight and pulling against/causing stress on the terminals. use relays for larger draw items like lights, fans, horns, electric fuel pumps etc, which allows a smaller gauge wire and switch to be used to switch the relay on and power the circuit. this allows under dash or in cab wiring to take up less space if the relay center is mounted closer to the need. part of the reason why newer vehicles have an under hood relay box.
here are a few links that may be of interest to someone doing wiring.

https://www.bluesea.com/support/arti...r_a_DC_Circuit

https://www.bluesea.com/support/arti...t_Installation

https://www.bluesea.com/products/cat...16/Fuse_Blocks

https://www.google.ca/search?q=tips+...=1605302186610

https://www.onallcylinders.com/2013/...iring-vehicle/

a good place to look for wiring components can also be the local stereo install shop. their equipment can have large current draws so they may keep cable, fuses, etc etc in stock. here is a quick read that can help determine conductor sizes.

https://www.crutchfield.ca/S-PtKIJHG...uge_chart.html

anyway, hope that helps.

11-13-2020, 05:22 PM	#12
dsraven Registered User Join Date: Nov 2010 Location: calgary alberta Posts: 7,839	Re: Bus Bar -Electrical--Clean and Efficient recently I rewired a burnt motorhome dash where the previous owner did a bit of wiring that caused the fire. there were many circuits taken off an inadequately supplied bus bar and when too many things were turned on the heat caused the insulation on the inadequately gauged, unfused supply wire to melt off, short to ground and start the fire. I used an under dash, insulated, color coded, terminal stud, supplied with battery positive through appropriately sized cable, and connected to a mega fuse under the hood near the battery that would interrupt the supply very close to the source should a problem ever occur. I have worked on a lot of highway trucks in years past and found that some had the same wire color through out. if the insulating loom were peeled back far enough the wires were actually labelled on each wire as to what the circuits were. sounded good in theory but in actual practice it was a pain to work on. unlike the factory floor there are a lot of things added to the vehicle after the wiring is placed and covered up. I spent lots of time upside down in a cab with my head stuck in the console peeling back old black tape from the loom so I could trace wires back to a problem somewhere. suggestions: check the max load on any given circuit (like if everything was running at max at the same time). before you build the circuit. leave some room for safety as far a wire gauge goes. fuse the supply wire at the source. fuse the circuit wires at THEIR source (like the fuse box or bus bar). use quality crimping tools and connectors. use double wall shrink tube on connections. double wall shrink tube has the insulating sheath on the outside but also has "hot glue" on the inside that melts when the tubing is shrunk around the connector so the tube doesn't move around on the wire later plus the glue adds a bit more insulating factor to the connection by taking up space between the wire strands and the tube outer surface. label the circuits. run the wire through a loom to protect against mechanical damage. tie the loom up periodically to protect against the harness sagging under it's own weight and pulling against/causing stress on the terminals. use relays for larger draw items like lights, fans, horns, electric fuel pumps etc, which allows a smaller gauge wire and switch to be used to switch the relay on and power the circuit. this allows under dash or in cab wiring to take up less space if the relay center is mounted closer to the need. part of the reason why newer vehicles have an under hood relay box. here are a few links that may be of interest to someone doing wiring. https://www.bluesea.com/support/arti...r_a_DC_Circuit https://www.bluesea.com/support/arti...t_Installation https://www.bluesea.com/products/cat...16/Fuse_Blocks https://www.google.ca/search?q=tips+...=1605302186610 https://www.onallcylinders.com/2013/...iring-vehicle/ a good place to look for wiring components can also be the local stereo install shop. their equipment can have large current draws so they may keep cable, fuses, etc etc in stock. here is a quick read that can help determine conductor sizes. https://www.crutchfield.ca/S-PtKIJHG...uge_chart.html anyway, hope that helps.