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I have a motor for a cone crusher that had a loose connection. I tightened that up and they ran the season on it. Now the crusher is back in the shop for rebuild and I took one connection apart. The feeds to the motor are two parallel 250 RHH stranded CU and motor leads are smaller cables. I was thinking of replacing the lugs with a six port Polaris type connection. Vibration is my concern. What’s the pros and cons. Price is of no concern.
 

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Chief Flunky
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Not that mining really cares all that much about NEC and Listing, BUT...this is the 3M recommended procedure. It has worked for decades under all conditions, vibration, etc. Unless the alternative is superior, why change?


Polaris Black is not rated for fine stranded wire and is dry location only.


Granted they do have submersible plugs rated for wet locations but again not rated for fine stranded wire:


OK, so then the answer is the grey connectors right?


As per Polaris marketing, "DLO Cable, Motor Lead Wire, Welding Cable, Entertainment Cable and Portable Power Cable. Excellent for use in all Motor Connect or Re-Connect applications, Portable Power and Lighting in the industrial, mining and entertainment industry, welding cables and power supply cables." Apparently they know very little about their customer base though. Don't look at the fine print in the upper right corner saying "dry location only" or at the pathetically small 2/0 limit for fine strand. In our motor shop we do limit ourselves to 4/0 before we go with multiple conductors which is pretty small compared to building wiring, but still you can't use motors with 3/0 or 4/0 leads. So if they are going after the guys that use split bolts and wire nuts, fine. But it better be an awfully small crusher to be using 2/0 wiring.

You can also look at other vendors like Burndy but it will not change the fact that you can't get wet location AND fine stranded wire AND in large enough sizes to be useful. Trust me, I've looked at this for years. More as a customer than a vendor.

In addition check out those torque ratings! They are 2-3 times less than what you can get with a bolted connection using hardened steel grade 8 bolts and Nylocks. It took me a while to figure out why every time I tried to use one I stripped out the set screw in 2 seconds until I noticed how low the torque specs are. I have to bump down even my 3/8" impact to the lowest setting. Most guys with impacts are going to severely overtorque the bolts they use with lugs but it will still work. The aluminum set screw will just gall or strip.

The second issue is kind of counter intuitive. It would seem like with rubbers that the harder the rubber (higher durometer), the tougher it would be where very soft "gummy" rubbers would be weaker and less abrasion resistant. Nothing can be further from the truth! Natural "gum" rubber is used for lining hydrocyclones and other applications that need high wear resistance. "Harder" rubbers are less resistant to impact and abrasion. 130C rubber splicing tape gives you and the direct opposite of the hard rubber used on a Polaris plug. You will find the Polaris plugs will probably survive the first year but a properly lugged and taped connection lasts the life of the motor. Polaris plugs don't last nearly as long. If I was a construction contractor (here today, gone tomorrow, repeat business what's that?) of course it's not an issue but my customers are 99% repeat customers.

The third issue is that man those things are bulky! On top of the fact that a peckerhead refers to the engineers that design them based on the absolute bare minimum space required, it is darned near impossible to keep a Polaris plug from rubbing. With bolted connections the whole trick is to tape or tie wrap everything in a crusher tight enough so that it can't rub against anything or itself. If it can rub, line whatever it can rub on with rubber or glastic or even wood placed strategically so that it can't rub on the edges of the box or the bolts or the ground lugs. A lot of guys seem to think there is some kind of Code that says that you MUST place a 2x4 across the front of the box to keep the wiring from rubbing against the edges. Remove that board and they will have a hissy fit. Polaris plugs are the same but even worse. I've had them last anywhere from a month to a couple years at most before they rub through that hard rubber. Bolted and taped joints as I said though...decades or more without any problems at all.

Fourth, that connector is going to booger up every wire you stick in it. You are supposed to cut the end off and redress the wiring such every time you crush it with a mechanical lug, it permanently deforms the wire out of shape. Nobody does this every time of course but the fact remains that at least every 3rd time or so it is so fine strand wiring gets so boogered up you will have to redo it, and coarse strand SPREADS so much that you can't get it back into shape and have to redo it. That's fine for the MOTOR side since by then it will need rewinding but you will slowly eat up the feeder cables too. If they are lugged, it's once and done. Only thing that needs replacing is the hardware once in a while.

Final issue is price. As in holy cow...these things better be WAY better. They are a huge step up from split bolts and wire nuts but again going back to the beginning...if the 3M recommended motor splicing procedure is lugs and tape, why promote a product that is not intended for a motor environment and falls way short of the sizes needed? I realize time is money but how much money do you save having to redo the termination during normal production after you blow a lead off?

If you really, really hate taping that much, to the point where you will spend a huge amount of money on goofy connectors, have I got a deal for you! 3M has premolded covers that just go right over the lugs so you hardly have to do any taping at all:

I've tried these things and also tried using F1 tape for YEARS. I've given them both a fair shake. I've had failures with both of them. I've had a few bolted lug terminations fail too but it has been a LOT less.
 

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Registered
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Discussion Starter · #11 ·
Not that mining really cares all that much about NEC and Listing, BUT...this is the 3M recommended procedure. It has worked for decades under all conditions, vibration, etc. Unless the alternative is superior, why change?


Polaris Black is not rated for fine stranded wire and is dry location only.


Granted they do have submersible plugs rated for wet locations but again not rated for fine stranded wire:


OK, so then the answer is the grey connectors right?


As per Polaris marketing, "DLO Cable, Motor Lead Wire, Welding Cable, Entertainment Cable and Portable Power Cable. Excellent for use in all Motor Connect or Re-Connect applications, Portable Power and Lighting in the industrial, mining and entertainment industry, welding cables and power supply cables." Apparently they know very little about their customer base though. Don't look at the fine print in the upper right corner saying "dry location only" or at the pathetically small 2/0 limit for fine strand. In our motor shop we do limit ourselves to 4/0 before we go with multiple conductors which is pretty small compared to building wiring, but still you can't use motors with 3/0 or 4/0 leads. So if they are going after the guys that use split bolts and wire nuts, fine. But it better be an awfully small crusher to be using 2/0 wiring.

You can also look at other vendors like Burndy but it will not change the fact that you can't get wet location AND fine stranded wire AND in large enough sizes to be useful. Trust me, I've looked at this for years. More as a customer than a vendor.

In addition check out those torque ratings! They are 2-3 times less than what you can get with a bolted connection using hardened steel grade 8 bolts and Nylocks. It took me a while to figure out why every time I tried to use one I stripped out the set screw in 2 seconds until I noticed how low the torque specs are. I have to bump down even my 3/8" impact to the lowest setting. Most guys with impacts are going to severely overtorque the bolts they use with lugs but it will still work. The aluminum set screw will just gall or strip.

The second issue is kind of counter intuitive. It would seem like with rubbers that the harder the rubber (higher durometer), the tougher it would be where very soft "gummy" rubbers would be weaker and less abrasion resistant. Nothing can be further from the truth! Natural "gum" rubber is used for lining hydrocyclones and other applications that need high wear resistance. "Harder" rubbers are less resistant to impact and abrasion. 130C rubber splicing tape gives you and the direct opposite of the hard rubber used on a Polaris plug. You will find the Polaris plugs will probably survive the first year but a properly lugged and taped connection lasts the life of the motor. Polaris plugs don't last nearly as long. If I was a construction contractor (here today, gone tomorrow, repeat business what's that?) of course it's not an issue but my customers are 99% repeat customers.

The third issue is that man those things are bulky! On top of the fact that a peckerhead refers to the engineers that design them based on the absolute bare minimum space required, it is darned near impossible to keep a Polaris plug from rubbing. With bolted connections the whole trick is to tape or tie wrap everything in a crusher tight enough so that it can't rub against anything or itself. If it can rub, line whatever it can rub on with rubber or glastic or even wood placed strategically so that it can't rub on the edges of the box or the bolts or the ground lugs. A lot of guys seem to think there is some kind of Code that says that you MUST place a 2x4 across the front of the box to keep the wiring from rubbing against the edges. Remove that board and they will have a hissy fit. Polaris plugs are the same but even worse. I've had them last anywhere from a month to a couple years at most before they rub through that hard rubber. Bolted and taped joints as I said though...decades or more without any problems at all.

Fourth, that connector is going to booger up every wire you stick in it. You are supposed to cut the end off and redress the wiring such every time you crush it with a mechanical lug, it permanently deforms the wire out of shape. Nobody does this every time of course but the fact remains that at least every 3rd time or so it is so fine strand wiring gets so boogered up you will have to redo it, and coarse strand SPREADS so much that you can't get it back into shape and have to redo it. That's fine for the MOTOR side since by then it will need rewinding but you will slowly eat up the feeder cables too. If they are lugged, it's once and done. Only thing that needs replacing is the hardware once in a while.

Final issue is price. As in holy cow...these things better be WAY better. They are a huge step up from split bolts and wire nuts but again going back to the beginning...if the 3M recommended motor splicing procedure is lugs and tape, why promote a product that is not intended for a motor environment and falls way short of the sizes needed? I realize time is money but how much money do you save having to redo the termination during normal production after you blow a lead off?

If you really, really hate taping that much, to the point where you will spend a huge amount of money on goofy connectors, have I got a deal for you! 3M has premolded covers that just go right over the lugs so you hardly have to do any taping at all:

I've tried these things and also tried using F1 tape for YEARS. I've given them both a fair shake. I've had failures with both of them. I've had a few bolted lug terminations fail too but it has been a LOT less.
All this I have to agree with. The issue is space, the way they lugged this motor, looks like a bad hair day. The rubbing inside the JB is excessive. There are rubber covers on the terminations and I still see rub throughs. I guess I knew the bolted lugs were better. That’s why I haven’t cut them off yet. Just thought someone would come on with a real world experience of how good the Polaris lugs would be. In the mill it was cambric/friction/rubber/vinyl. And sometimes we would put duct seal around the bolts to soften the hard corners.
 

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Big nosed attic troll
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10,711 Posts
All this I have to agree with. The issue is space, the way they lugged this motor, looks like a bad hair day. The rubbing inside the JB is excessive. There are rubber covers on the terminations and I still see rub throughs. I guess I knew the bolted lugs were better. That’s why I haven’t cut them off yet. Just thought someone would come on with a real world experience of how good the Polaris lugs would be. In the mill it was cambric/friction/rubber/vinyl. And sometimes we would put duct seal around the bolts to soften the hard corners.
whats the amps on your motor?
 

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Registered
Scada Supervisor
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4,267 Posts
All this I have to agree with. The issue is space, the way they lugged this motor, looks like a bad hair day. The rubbing inside the JB is excessive. There are rubber covers on the terminations and I still see rub throughs. I guess I knew the bolted lugs were better. That’s why I haven’t cut them off yet. Just thought someone would come on with a real world experience of how good the Polaris lugs would be. In the mill it was cambric/friction/rubber/vinyl. And sometimes we would put duct seal around the bolts to soften the hard corners.
I have seen peckerheads filled with sheet rubber or mastic pads also on high vibration applications.
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Bilge Rat
motors and controls.........
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I've never seen cripm lugs burn up but I have seen Polarises fail, even the gray ones that are designed for fine strands.

If you do use Polarises, put the wire in as follows......power in, motor, power in, motor or power, motor, motor, power. This way, the polaris doesn't conduct the full current of the motor, it's spread out, so to speak.
 
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