We need to remember that while proper torque is important, those tables were engineered on static (non-mobile) systems. RV are subjected to major vibrations so all connections should be checked regularly. I wonder if some kind of thread locker product might be a best practice for RV's ?????
My rules for bus bars: (also applies to battery connections).
1. Make sure that the bus bars are rated for at least the amount of current you expect to ever have going through them. Use UL rated bus bars and not home made ones.
2. Never place a washer between the wire terminal and the bus bar. The wire terminal and bus bar should have a direct surface to surface contact. The flat washer should go on top of the terminal and the lock washer on top of that.
3. If you have multiple terminals connected to a single stud, have the largest (highest current) wire on the bottom and the smaller ones on top. Never stack more that 4 terminals on one stud.
4. Make sure that no insulation, dirt, or corrosion gets between the surfaces.
5. Where possible, place the biggest current source (the battery) in the middle of the bus bar and the biggest load (usually the inverter) right next to to the battery. This way the largest currents don't have to travel from one end of the bus bar to the other.
6. With stainless steel hardware it is best practice to place a tiny bit of dielectric grease on the threads to prevent galling.
7. Always use tin plated copper (marine rated) terminals in areas that will be exposed to the elements or possibility of corrosion (such as lead acid batteries).
Sorry, one more: Never use a wing nut. Always use a hex nut and tighten to proper torque. I don't like to use the flange nuts with integrated locking mechanism. I prefer to replace them with a regular stainless steel hex nut with a separate lock washer.
As a rule of thumb I have gotten where I use Noalox or dielectric grease on every exterior thing that plugs in , such as main power cord, bayonet or blade connections for lights and switches etc. I also coat battery terminals. That said I had not thought about. points that are torqued down.
Mike, you note "lightly lubricated" terminals when replacing or re-seating these connections. Do you recommend noalox, dielectric silicone grease or either?
I’m studying best practices for that right now. I know that rusty (oxidized) threads will create less than optimal compression for a given torque, and oiling the threads can create too much compression at a given torque. So there has to be a happy medium. Standby…
Even though I always disconnect the negative terminal first, working in a close area with several batteries, cables, and associated equipment is dangerous. After seeing the after effects of a positive to negative battery terminal contact with a wrench I take it very seriously. Therefore I keep a set of wrenches that have been dipped in plastic except for just at the end. One set is open end with the box end insulated and the other has the open end covered. This is cheap prevention compared to a very bad outcome. Always inspect your tools before doing any work around batteries.
You are wise to be cautious. And I’ve also done the same trick of dipping wrenches in a plastic insulating “paint”. They used to sell it at Lowes decades ago, so I’ll have to look for a modern version.
We need to remember that while proper torque is important, those tables were engineered on static (non-mobile) systems. RV are subjected to major vibrations so all connections should be checked regularly. I wonder if some kind of thread locker product might be a best practice for RV's ?????
I have a contact at LocTite. I’ll give them a call…
My rules for bus bars: (also applies to battery connections).
1. Make sure that the bus bars are rated for at least the amount of current you expect to ever have going through them. Use UL rated bus bars and not home made ones.
2. Never place a washer between the wire terminal and the bus bar. The wire terminal and bus bar should have a direct surface to surface contact. The flat washer should go on top of the terminal and the lock washer on top of that.
3. If you have multiple terminals connected to a single stud, have the largest (highest current) wire on the bottom and the smaller ones on top. Never stack more that 4 terminals on one stud.
4. Make sure that no insulation, dirt, or corrosion gets between the surfaces.
5. Where possible, place the biggest current source (the battery) in the middle of the bus bar and the biggest load (usually the inverter) right next to to the battery. This way the largest currents don't have to travel from one end of the bus bar to the other.
6. With stainless steel hardware it is best practice to place a tiny bit of dielectric grease on the threads to prevent galling.
7. Always use tin plated copper (marine rated) terminals in areas that will be exposed to the elements or possibility of corrosion (such as lead acid batteries).
Sorry, one more: Never use a wing nut. Always use a hex nut and tighten to proper torque. I don't like to use the flange nuts with integrated locking mechanism. I prefer to replace them with a regular stainless steel hex nut with a separate lock washer.
As a rule of thumb I have gotten where I use Noalox or dielectric grease on every exterior thing that plugs in , such as main power cord, bayonet or blade connections for lights and switches etc. I also coat battery terminals. That said I had not thought about. points that are torqued down.
It would be smart to paint a line across the tightened screws so that you could see quickly if anything has moved.
Mike, you note "lightly lubricated" terminals when replacing or re-seating these connections. Do you recommend noalox, dielectric silicone grease or either?
I’m studying best practices for that right now. I know that rusty (oxidized) threads will create less than optimal compression for a given torque, and oiling the threads can create too much compression at a given torque. So there has to be a happy medium. Standby…
Even though I always disconnect the negative terminal first, working in a close area with several batteries, cables, and associated equipment is dangerous. After seeing the after effects of a positive to negative battery terminal contact with a wrench I take it very seriously. Therefore I keep a set of wrenches that have been dipped in plastic except for just at the end. One set is open end with the box end insulated and the other has the open end covered. This is cheap prevention compared to a very bad outcome. Always inspect your tools before doing any work around batteries.
You are wise to be cautious. And I’ve also done the same trick of dipping wrenches in a plastic insulating “paint”. They used to sell it at Lowes decades ago, so I’ll have to look for a modern version.
I also insulate my battery wrench. I used heavy duty heat shrink tubing (dual wall).