mark32
Senior Member
- Location
- Currently in NJ
For those that use torque wrenches on their terminations, do you ever question them?
For example, I swapped out a FP panel today with a 150 amp main breaker Square D Homeline panel. The labeling recommends 250 in.lbs for the main terminals for #4-250mcm. I got up to 150 in.lbs and left it at that. At that point, I felt like the aluminum lug wouldn't take much more, certainly not 100 in.lbs more, before stripping out. I also question the validity of the values because of the wide range of wire sizes, yet they all have the same value? The optimum torque for a #4 conductor is the same as 250mcm? Even the smaller gauges seem off, 14-10 awg is 20 in.lbs for the neutral bars. 20 in.lbs is like nothing for a solid #10. I like doing things the right way, which is why I purchase and use torque wrenches when doing electrical and auto work. I'm sure all of us have, at one time or another, stripped out a bolt hole or snapped off a bolt and once that happens you never really forget that feeling, it's terrible and one that you want to avoid, of course This is not the first time I've struggled with trying to abide by the recommended torque values and fearing I'm about to damage some equipment. Anyway, I wanted to hear some thoughts from my colleagues about it.
For example, I swapped out a FP panel today with a 150 amp main breaker Square D Homeline panel. The labeling recommends 250 in.lbs for the main terminals for #4-250mcm. I got up to 150 in.lbs and left it at that. At that point, I felt like the aluminum lug wouldn't take much more, certainly not 100 in.lbs more, before stripping out. I also question the validity of the values because of the wide range of wire sizes, yet they all have the same value? The optimum torque for a #4 conductor is the same as 250mcm? Even the smaller gauges seem off, 14-10 awg is 20 in.lbs for the neutral bars. 20 in.lbs is like nothing for a solid #10. I like doing things the right way, which is why I purchase and use torque wrenches when doing electrical and auto work. I'm sure all of us have, at one time or another, stripped out a bolt hole or snapped off a bolt and once that happens you never really forget that feeling, it's terrible and one that you want to avoid, of course This is not the first time I've struggled with trying to abide by the recommended torque values and fearing I'm about to damage some equipment. Anyway, I wanted to hear some thoughts from my colleagues about it.