Motor Connection Options

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Vankirk Electric SR. PM

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Winder, Ga
Scenario:
An inspector in San Jose, CA is telling us that we can't use split bolts for our motor lead connections. We have (1) 3/0 per phase feeding the 3-phase motor. The motor has (4) #8 conductors per phase. We need a solution for connecting the 3/0 to the (4) #8's... keep in mind that space is limited since we are working in the small junction space of the pump. Picture below shows you what we currently have with the split bolts. Thanks for the help.

Unknown.jpg
 
My motor connections are always crimp lugs and bolts and insulated with either rubber and plastic tape or Raychem GelCaps.
 
Do you have room to get a 'power distribution block' in there?

http://www.cooperindustries.com/con...ributionblocksterminalblocks/pdb_series_.html

The other thing that I've seen are crimped ring terminals on all of the leads, bolted together and insulated with tape like a split bolt.

I admit to being at a loss, since for the motors we build we do our best to have a single wire per supply phase coming out of the motor, and for the few 3 phase motors that we use as test loads we cheat and use split bolts ;)

The inspector is correct, in that the split bolt is likely not rated for joining 5 conductors together...though if you could get a split bolt with an appropriate listing then the install is legal.

-Jon
 
Are the split bolts rated for (4) #8's & (1) #3/0?
If so, then he should permit it.
 
Burndy says no more than 3 conductors, and the version for 3/0 would not allow #8 stranded as a tap connection (#8 solid only). He would have to go to the 250KCmil version, and even then it's still 3 conductors.

Old school: ring lugs, bolted, varnish Cambric, #88 rubber, finish with #33 on top for the win.
 
Jraef said:
Burndy says no more than 3 conductors, and the version for 3/0 would not allow #8 stranded as a tap connection (#8 solid only). He would have to go to the 250KCmil version, and even then it's still 3 conductors.

Old school: ring lugs, bolted, varnish Cambric, #88 rubber, finish with #33 on top for the win.
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He was old school with the split bolts. I learned to top them off with a piece of inner tube. New fangled stuff :rant:. :D
 
wireman said:
Are the split bolts rated for (4) #8's & (1) #3/0?
If so, then he should permit it.
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As far as I know there are no split bolts listed for more than three conductors. Most are only listed for two and a few are listed for 2 or 3.
 
maybe something like BURNDY 1PL2/0-2 tap?
 
don_resqcapt19 said:
My motor connections are always crimp lugs and bolts and insulated with either rubber and plastic tape or Raychem GelCaps.
Click to expand...
Similar here. For small machines we use insulated crimp lugs. For larger machines we use compression lugs and heat shrink sleeving.
 
Besoeker said:
Similar here. For small machines we use insulated crimp lugs. For larger machines we use compression lugs and heat shrink sleeving.
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how will 4 lugs connect and fit into the small motor box? i guess they'll need to be splayed apart, maybe two sets of back to back and then those bolted together?? once you splay them then how do they get insulated?
 
FionaZuppa said:
how will 4 lugs connect and fit into the small motor box? i guess they'll need to be splayed apart, maybe two sets of back to back and then those bolted together?? once you splay them then how do they get insulated?
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Two 8s with the lugs back to back, splayed out just enough for the barrels to clear the barrels of the other two 8s, and bolted to the 3/0 lug. Not a big deal to tape that up with rubber tape. Even easier to insulate with a GelCap. Not matter what method you want to use, some motor junction boxes are too small :) I have removed motor junction boxes and replaced them with a NEMA 4 junction box a number of times where I needed more termination space.
 
Never from my recollection have I had an inspector remover a cover from a motor box.

That said Polaris taps (or equivalents) are used a lot, but technically you can't put multiple motor leads in one port, like on dual voltage motors where multiple leads tie together. The most common ones probably are not listed for fine strand conductors either - some motor leads are fine stranded. As mentioned split bolts also are usually only rated for two conductors, yet I have seen split bolts used quite a bit for motor connections as well.

Many motors anymore already have crimped on ring terminals and apparently they intend you to bolt them together. If they are small leads I often wire nut them - though some think that is a cardinal sin, I haven't had that much trouble with it. Worst experience for me was a sifter machine that the motor is mounted on the shaking part of the machine - nothing seems to last in there unless you stuff the box with some sort of packing to hold everything in place though - fiberglass insulation is what we have been using on it and have had to replace motor bearings before needing to repair wires in the terminal box ever since.
 
Vankirk Electric SR. PM said:
Scenario:
An inspector in San Jose, CA is telling us that we can't use split bolts for our motor lead connections. We have (1) 3/0 per phase feeding the 3-phase motor. The motor has (4) #8 conductors per phase. We need a solution for connecting the 3/0 to the (4) #8's... keep in mind that space is limited since we are working in the small junction space of the pump. Picture below shows you what we currently have with the split bolts. Thanks for the help.

View attachment 18899
Click to expand...
I am curious how the inspector saw that as the other two are bugged already. Did he ask to see it? Seems like something not seen on the rough and all buttoned up on the final
 
Jraef said:
...#88 rubber...
Click to expand...
???

Super 88 a premium grade, 0.2mm thick, all-weather vinyl insulating tape. Super 33+ is quite similar but only 0.178mm thick.


Perhaps you meant 130C...?

Yes, there are others but 130C is what 'we' commonly use around here.
 
Tony S said:
Please excuse my lack knowledge of US practice, surely motors come equipped with some form of permanent connection block? Why do you have to jury rig what should be a simple connection?
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Good question. NEMA motors typically just have cut ends on smaller motors, and quite often a crimped on ring terminal on each lead for larger motors - but they are not terminated to anything, and there normally isn't space for a connection block when there is larger conductors involved.

Most of the smaller general purpose motors, less then ~60 hp, have a need to configure leads for either 208-240 or 480 volts so there is more then just three input leads on a basic three phase motor. Over ~60 hp they still have at least six leads brought out to the terminal box in most cases so that part winding start can be an option.
 
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