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Chief Flunky
Field Service Engineer
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So long story short there are some 600 mcm feeders that due to settling are getting to the point of being to short. I talked with a contractor today about possibly splicing on a short piece to the end to save them. I'm just curious what would be the best option for wire this big. Big hydraulic crimp barrel? Polaris type lugs ? Old school eye barrels and tape? I don't have any knowledge of splicing this big of wire (hence bring in a contractor) but just want to learn what's out there.
I handle large above NEMA motors, starters, and drives all the time. I carry #22 to 500 MCM lugs and tools stock on the truck. I carry terminations to 15 kV too. Customers that know this sometimes just call to buy lugs in emergencies.

Depends on you needs. Hands down Cadwelded terminations/splices are the most permanent. Next to that crimped termination nations are permanent but more or a cold rather than hot weld. Utilities use cadweld underground on ground grids in substations and crimped lugs everywhere else. Some even spec it for control wiring.

Whether to use a bolted pair or lugs or a barrel connector is a function choice: Barrel connectors are cheaper but you can never take them apart: Once you crimp it on removal means cutting off more cable. With lugs you have options. There might be a tiny bit more risk but bolt failures are either lack of proper sizing, not tightened or galled, or bad tape jobs.

Insultaps or Polaris taps work for a while. I have replaced many failed ones. Like any mechanical lug you have a huge working size range but higher failure risk. The crimp stuff is very idiot proof. On my crimper I hold the trigger until it finishes and retracts. On my manual you squeeze until the pressure relief trips. On an Allen head 85% of the torque goes into overcoming thread friction. How do you know how much tension you applies? You don’t. That’s on top of the tendency for aluminum and brass set screws to strip or gall or jam on a thread of wire. Lugs are so much easier.

There can be a Code issue. You aren’t supposed to have joints in the middle of raceways. Strict interpretation means pulling out the old cable. Cadweld really is not a joint. You can argue barrel connectors aren’t either. All others can be taken apart so it’s as legal as using wire nuts in a conduit body.

The splicing decisions are the SAME no matter the size. You just have fewer options at larger sizes. I’m sure Mike will be along any time now to talk about Wago Levernuts but I have not seen a 600 MCM Wago. I have seen that size cam locks and pin connectors but that’s another story.
 

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Chief Flunky
Field Service Engineer
Joined
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3,592 Posts
So are these things that you crimp on with a big hydraulic crimper? I assume so. Do they sell appropriate insulation sleeves or tape them up with the rubber tape or ?
Yes.

Correct (3M procedure) is two layers of varnished cambric to cover sharp edges but practice is anything really. Cloth, glass, or vinyl tape is often used. Then at least 2 layers of rubber splicing tape. Then 2 layers of vinyl tape.

You can also get heavy wall adhesive lined heat shrink for the ultimate waterproofing. Make sure to slide it on FIRST before crimping. In multiconductor cables stagger the joints. This is good practice anyway. Shrink one on per barrel then one overall (multiconductor only). I often buy the bigger ones from McMaster Carr. Next day delivery. The thing is though I’ve done thousands. Getting everything the right length and shrinking evenly takes a little practice so this is a terrible technique for one off attempts where tape is forgiving…you can always add more or cut it off and redo it. Heat shrink is pretty much once and done.
 

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Chief Flunky
Field Service Engineer
Joined
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3,592 Posts
The thing with the manual is it takes two hands and those hands can't be close to the work, so you kind of want a third hand to hold the wire in the connector.
Never a problem for me. I like to lay the crimper down if I can and insert the lug and better yet wire too but that’s not absolutely necessary. It’s a pretty rare day that I have to crimp in open air. That’s more of a lineman thing. Crimp just until it holds the fitting. Do NOT crush it yet, just enough to hold it. Then I can let go of the crimp and insert/hold the cable into the lug while using the other hand to pump the crimper. After a couple squeezes the wire is not going anywhere. On the rest of the crimps I can just rest the crimper against my hand (not on the die! Frame only) and repeat the procedure until they are all done. Just remember that once the crimper is applying pressure, it’s not going anywhere. Once the cable is being crushed, it’s not going anywhere. Put the first crimp out close to the shoulder. Subsequent crimps move towards the barrel opening. This way everything is held in place the whole time. If you need to you can always do another crimp closer to the lug shoulder but once the first crimp is on, forget ever removing the wire.

Hydraulic crimpers (true hydraulic) are cheap and very fast but the pumps are very expensive. At most we do maybe a hundred lugs in a day so we haven’t been able to justify the bigger tools yet.The slow part of the process stripping and pulling.
 
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