Proper Torque

[ishamael69]

So, the electricians who wired my 200 amp sub panel in the garage put two different size bus bars in. Both have isolated standoffs, but the ground is bonded to the box. Neither have green screws. The ground one is long, and the neutral is shorter.

This leads to my problem: I'm out of neutral spots. I can double up grounds, but not neutrals. So, my thought was to swap the bars. However, the aluminum service cables are of course mounted to the bus, and I don't know how to ensure they are properly torqued if I remove them. Also, I don't know if I need to regrease them.

Can I swap the buses? If so, how do I get proper torque? (The main breaker is actually in a separate box, so the entire box can be killed.) For that matter how do I know if I've been torquing the breakers correctly? I've been tightening them as tight as I can, but I just saw pics on here where a cable melted from over torquing, which I didn't know was an issue.

 

[matt_i]

I think the arcing fail pictured was from undertorquing not over torquing. Imo, you will have 95% of all torque-related electrical problems from undertorque. 5% from over torque of which 2/3 of the 5% will be from stripping the drive slot or the threads which leads to low clampload, ironically same failure mode as undertorque.

The best way to assure torque is to use an inch pound click wrench, set to the manufacturer's specifications for the lug in question.

 

[tyme2par4]

Using a regular screw driver on solid wire, it's very hard to over torque the connection. You don't need 2 hands on the screwdriver, but a good torque with one hand is going to be fine.
When you get up to larger wire sizes, toque becomes more important. It would be good to get a decent torque wrench for the main wires. I borrowed one from work when I did my main panel a few weeks ago.

 

[justsam]

What type of panel is it? Can you add another neutral bar and tie to existing neutral bar?

Based on your description is this a detached garage, with a 4 wire feed, 2 hot, 1 neutral, and one ground conductor, tied to a local ground rod at the detached garage?

 

[sberry]

Guys with lotso automotive experience tend to get it better. Last inspection the guy checked my main lugs and was pleased.
I aint scared to put a spritz of spray down the bars and a drop on some breaker screws if they are dry and squeaky, a dab of no lox on lugs to let all this tighten smoothly, doesn't seize and a film of light oil has to be a better thing for electrical equipment than bare dry metal and threads which accepts any condensate from day 1 like a sponge.

 

[sberry]

A couple of my early installs have been replaced, did one for a bud a while back would have been great to salvage but put together all dry and corroded which doesn't happen on my bit later installs since I treat the threads.

 

[wyliesdiesels]

So, the electricians who wired my 200 amp sub panel in the garage put two different size bus bars in. Both have isolated standoffs, but the ground is bonded to the box. Neither have green screws. The ground one is long, and the neutral is shorter.

This leads to my problem: I'm out of neutral spots. I can double up grounds, but not neutrals. So, my thought was to swap the bars. However, the aluminum service cables are of course mounted to the bus, and I don't know how to ensure they are properly torqued if I remove them. Also, I don't know if I need to regrease them.

Can I swap the buses? If so, how do I get proper torque? (The main breaker is actually in a separate box, so the entire box can be killed.) For that matter how do I know if I've been torquing the breakers correctly? I've been tightening them as tight as I can, but I just saw pics on here where a cable melted from over torquing, which I didn't know was an issue.

U should add an additional neutral bar on iso standoffs.

I wouldnt swap the bars.

That picture was posted by me. And the lug was most likely under torqued, not overtorqued.

U will need a torque wrench to make sure they are properly torqued.

 

[sberry]

Gearhead mechanics get this better than a lot of people and know what a small engine head bolt feels like and understand what it feels like and some experience can get a feel for putting a firm clamping force to a conductor.
With heavy stranded wire actually prefer to weigh it, clamp to 90%, wait a day and come back to snug it and don't want a dry squealing screw or lug bolt.