Workmanship or OCD

[AndyD]

They are available, at a hefty price. One of the problems with using screwdrivers, most people don't know the difference between a PH and PZ which is why you find so many stripped screws and you can't torque a stripped screw.

Bottom line, you would need to educate people about the difference between PH and PZ first, then all electrical components would require the torque setting printed on the device. I would be all for it, but in the real world, not gona happen.

You get Philips, Pozidrive, Superdrive, and you also get modulo philips and modulo pozidrive,also known as 'plus minus' screws which are flat and star at the same time and you see a lot on contactor and MCB termination screws. I also carry four different modulo screwdrivers in my toolcase. It's critical with modulo screwdrivers that you use the right one otherwise the blade cracks easily because all the torque ends up on one point if it's in a screw it doesn't fit properly.

[ians]

😀 Andy this is Africa. If you go to the wholesaler it is difficult enough trying to get a PZ screwdriver.

[Justloadit]

�� Andy this is Africa. If you go to the wholesaler it is difficult enough trying to get a PZ screwdriver.

More like a reply 'watz that?'
Recently went looking for 'Shelac' for a special kind of job, and none of the motor parts suppliers even knew what I was talking about, save for an old timer at an old place. We use to use it in the old days to seal oil sumps to the engine block.

[AndyD]

�� Andy this is Africa. If you go to the wholesaler it is difficult enough trying to get a PZ screwdriver.

If it's anything that's not high volume items all the wholesalers are absolutely useless.

This is the torque driver I use, it's gone up in price considerably from when I bought it though, I think I paid around R700 each for mine. Here's the modulo driver bits that fit it.

This is the normal screwdriver set I use, it comes with 2 x modulo (plus-minus) blades.

I should be gettng commission frm RS.

[AndyD]

More like a reply 'watz that?'
Recently went looking for 'Shelac' for a special kind of job, and none of the motor parts suppliers even knew what I was talking about, save for an old timer at an old place. We use to use it in the old days to seal oil sumps to the engine block.

Are you using it for repairing motor windings?
SPANJAARD LTD, Address: 748-750 Fifth Street, Wynberg, Sandton
Telephone Number:+27 (0)11 386-7100
sell a spray electrical insulatng varnish which can be used on most stators. If you're rewinding from scratch you need something a bit more serious.

We usually use Wilec for most stuff to do with rewinding. They sell a limited selection of insulating resins for trickle and vacuum impregnation of windings.

[Justloadit]

With tools like these makes screwing fun

[Justloadit]

Are you using it for repairing motor windings?
SPANJAARD LTD, Address: 748-750 Fifth Street, Wynberg, Sandton
Telephone Number:+27 (0)11 386-7100
sell a spray electrical insulatng varnish which can be used on most stators. If you're rewinding from scratch you need something a bit more serious.

We usually use Wilec for most stuff to do with rewinding. They sell a limited selection of insulating resins for trickle and vacuum impregnation of windings.

Nice stuff you pointing too.

No interestingly I am using it to seal case splitting extruded aluminium cases. Cleaning the excess is easier than silicone, and makes the opening of the case easier for repairs, and for resealing.

[ians]

I have a very expensive torque screwdriver( thermal imager) , it scans the connection after a couple days to see if it is getting warm.

There is another way to check your connection and works great for older circuit breakers, check the mV from the top of the breaker to the bottom.

[AndyD]

I have a very expensive torque screwdriver( thermal imager) , it scans the connection after a couple days to see if it is getting warm.

There is another way to check your connection and works great for older circuit breakers, check the mV from the top of the breaker to the bottom.

We also use thermal imaging on our panels but I think the difference is that thermography and even voltdrop only indicate the resistence of the terminations at that moment whereas using the correct tightning torque is insurance that there will be as little degradation of the termination as possible over time.

It's all relative however, if you're using fine stranded wire in compression terminals or if you're fitting your lugs and ferrules by squeezing them with a pair of sidecutters then tightning torques are the least of your worries but as an assembler our crimping tools and other assembly tooling has to be calibrated every year as well.

[ians]

Workmanship or OCD

I can understand all that for panel builders working in a cool environment with all his tools laid out on a work bench, but what about the electrician on site, working in hectic conditions under pressure to finish by a deadline, bad lighting with the risk of tools and equipment being stolen who are connecting twin + e, solid strand Or multi strand wires? Something else I have found with lower end circuit breakers, you tighten today, go back a week later and terminals are loose.

[ACEsterhuizen]

Put in a squirt and forget about it.

Electrically Conductive Adhesives been around for some time now.

[Justloadit]

The issue is not whether the screw unloosens by itself, but rather the pressure on the copper wire, along with heating and cooling, cause the copper to deform, and in so doing makes a poor mechanical then off course electrical connection. Locking the screw simply means that the next electrician doing maintenance gets fooled that the connection is tight, where in the meantime the screw is locked, but the copper has deformed and still makes a loose connection.

on home installations, the deformation of the copper may not be a big issue, because the currents involved are small, but in industrial applications where curent can be intheir hundreds, this becomes a major issue.

Another point to consider is the physical deformation of the copper wire may be due to poor manufacturing processes, where the annealing of the wire is not done correctly, which will lead to a softer copper wire, which is subject to easier deformation.

IMHO the torquing of the screws is to also ensure that one does not go past the 'bending moment' of the copper wire in which there is no return to its original state. So over tightening of the screw does not mean a better connection. In fact good practice is to place the copper wire into a ferrule and then compressing the ferrule onto the copper with the terminal. The ferrule ensures a complete compression of the copper evenly into the space allowed.

[ians]

Justloadit, once you get to higher levels of current it becomes a different league, by this I mean lugs, crimpers, nuts and bolts and torque wrenches. Which brings in another pile of issues like indent crimpers, hydraulic crimpers, crimping pressures etc etc etc .

[AndyD]

Many mechanical clamp terminals aren't suitable for use with stranded wire. When you tighten a clamp onto a bunch of wire strands the bunch can flatten or splay causing the terminal to seem loose at a later date. As said by Justloadit above you should ferrule or lug wires at terminations.

I'd never recommend using threadlock or any other setting adhesive agent to secure a termination. You can never accurately re-torque the screw after the application and you'd never be guarranteed a good termination again if it's ever undone and remade during fault finding for example.

I think every electrician, even one who only works on domestic, should own a decent indent crimper. Even a poor termination on a wire carrying a few Amps is enough to cause a house fire that could kill people.

[ians]

Don't get me wrong I agree with the idea of using torque wrenches. We just have to remember we live in Africa and when people can't tell the difference between a PZ and PH chances you aren't gona get a torque wrench to work unless you use the right bit. We have bigger issues to conquer in this industry.