# Motor Connections- How Do You Do Yours?



## 4GSR (Aug 27, 2016)

As the title says, "What method do you use for making your motor connections?"  I'm refering to promarly for 1 HP and larger motors, single and 3-phase, excluding stepper motors or any motors that have it's own kind of connectors.

The method I use, taught by my dad, is to use ring terminals on all motor leads and line wires coming into the pecker head.  Connections are bolted with stainless or brass screws and nuts.  Cover the connection with Scotch 2242 rubber electrical tape. Last a layer of Scotch 33 or 88 vinyl electrical tape.

Who wants to go next?


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## John Hasler (Aug 27, 2016)

Ring terminals or compression fittings.  I prefer shrink-tube boots to rubber tape though I will use the tape.  The vinyl tape is a waste of time: it always falls off.


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## Ulma Doctor (Aug 27, 2016)

80% of the OEM,  NEMA motors  in the industry i service use wire nuts to 10 hp,  the IDEC motors are ring terminated in the motor .
ring terminals and brass screws and electrical tape exclusively for motors manufactured by the Hobart Corporation.

+1 on 3M tape or any other 3M product for that matter!


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## Tony Wells (Aug 27, 2016)

Same as John. Gets kind of crowded to do a decent tape job, but lots of that is done. Whoever invented shrink tubing deserves a pat on the back. I have a bit left from some lithium battery packs I built for Tensor, high temperature stuff with a good shrink ratio. I will hate to have to replace it. I recall it being pretty costly.


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## JimDawson (Aug 27, 2016)

Like Mike, I use wire nuts up to 10HP on NEMA motors.  I normally don't tape wire nutted connections.  Above that the wire sizes are really too big for wire nuts, so I use split nuts, rubber tape, then vinyl tape.

Never thought of using shrink tube, but I like the idea! 

I don't like ring terminals/bolts, because that adds another layer(s) of connection that can fail over time, especially in wet/outdoor locations.  I have had connections fail on IEC motors due to terminals failing.  Those get replaced with wire nuts or split nuts.

In corrosive locations, think sewage treatment plant (ammonia and copper don't get along well), the connections get filled with anti-corrosion goo.


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## Bob Korves (Aug 28, 2016)

Old school.  Start watching at 17:30.  Stan is a true pro millwright and knows how to do things right.  If Stan wired my own deep space probe, I would be happy to live in it...
This is only one method of wiring, but it is solid and proven.


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## mksj (Aug 28, 2016)

On anything above 24V, I usually use ring terminals on the motor end, crimped, then the tips are wick soldered and then fusible shrink tubing over the crimp/wire and if used, the shield foil. If the motor has a terminal block then it is a direct connect, you can use some sealant/film over the terminals if in a corrosive environment. In the marine environment for battery terminals and such with copper wire, soldering fills any void area and protects the wires from corrosion in the crimp. Do not let the solder flow down the wire past the crimp.  The fusible shrink tubing protects the crimp/insulation and secures the wire. A bit of overkill especially when using an industrial crimper, the wire will fail before the wire pulls out of the crimp. If the motor does not have a terminal block, I prefer to use a separate terminal block as shown, I mount it to the housing if there is enough room in the connection box. These type of terminal blocks have a snap in cover, which prevents a terminal being shorted/touched. On the power end, I either will use ring terminals or locking spades, they are easier to get into some terminals and are hard to pull out. I use a touch of blue Locktite on the motor terminals or a screw connection exposed to vibration.

Wire nuts are common, I have seen corrosion and oxidation occur over time, when used in these type of connections I wrap them with electrical tape to minimize moisture and possible loosing. If it is in a hostile environment, you can get the waterproof wire nuts, and then tape.


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## Tony Wells (Aug 28, 2016)

There exists also a gel filled shrink tubing for harsh environments. I had forgotten about that. Pretty handy stuff too.


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## dieselshadow (Aug 28, 2016)

On bigger motors I use split-bolts, wrap vinyl tape inside out for a few wraps, then wrap in rubber tape, then a final layer of vinyl tape. The fist layer of vinyl tape sticky side out really helps when you need to unwire the motor. You can easily re-use the split-nut because the tape will come off clean. A quick swipe with a fresh razor blade and it all comes off.


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## jim18655 (Aug 28, 2016)

For those that tape their connections - start the tape on the wire then flip it over and put several layers on sticky side out. Now the rubber tape and follow with vinyl to hold the rubber. When you have undo the connection just cut through the layers and the tape will come right off like a rubber boot.


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## jim18655 (Aug 28, 2016)

Looks like we posted at the same time!


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## John Hasler (Aug 28, 2016)

Tony Wells said:


> There exists also a gel filled shrink tubing for harsh environments. I had forgotten about that. Pretty handy stuff too.


Yes, that's great stuff.  Well drillers use it for submersed connections.  The heat that shrinks the tubing also makes the gell set up.


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## 4GSR (Aug 28, 2016)

Speaking of heat shrink tubing, is there a "industrial strength" tubing that is thicker than the hardware store stuff is?  The stuff seems awful thin for insulation of wires. Or is this normal and safe to use in place of vinyl electrical tape?


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## Tony Wells (Aug 28, 2016)

Different thicknesses and hence dielectric ratings are available, as well as different shrink ratios. Some, like you mentioned, seems thin and I would only use it for class 2 wiring, but there is heavier stuff.


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## Splat (Aug 29, 2016)

I do it the way Bob Korves (and Stan on the video) does it. To weatherproof the connection I use 3M's Temflex tape and top it off with a layer of 33+. I used to crimp and then solder connections but having been taught by a few old time electrical engineers I don't now, but that's my preference. A proper crimp will last. Do it right the first time. BTW, I've used those gel filled connectors when we had a well. Twenty years later when we pulled it I was floored how great the connection was after all that time. I swear it looked like the day we first used it! Amazing stuff.


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## Keith Foor (Aug 29, 2016)

Anything that will fit (7.5 HP and below) the 3 tied motor leads get twisted together and then a crimp cap put on.  Crimp caps look like a wire nut but physically get compressed with a crimper.  Side note on crimpers.  There are varying levels or quality of crimpers.  There are also double and single crimp crimpers.  I strictly use a double crimp tool.  They compress any connection two different places.  Once I get into wiring that is larger than wire nuts can handle. (I also use a wire nut wrench on all wire nuts.  This allows a good torque to be applied to the nuts.)  It depends on the connection.  If there is space I get a terminal block similar to the one in the video and use copper or silver anti-seize (blocks are typically aluminum and don't care for copper wire).  I have a preference of allen screws over flat head so I can torque them to spec.  This is done if the connection is going possibly need removed lather on.  If the connection is permanent or semi-permanent, I use the Burndy compression barrels and wrap butyl rubber tape and then a layer of Super 33 for anything permanent.  These are a one use splice and crimpers for them are costly (150 for a cheap set) but they are a high compression tin over copper 1/16 wall tube that is exposed to over 2000 lbs of crimping force during compression.  They are effectively real lugs, and not to be confused with the standard ring and spade red yellow and blue stuff you find at an auto parts or home improvement store.  This is what the electric company uses to connect your house to the mains coming in from a pole.


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## Keith Foor (Aug 29, 2016)

Now on a side note.  I work in the radio communications field to pay the bills.  I have found an interesting thing called a courtesy wrap.  That is a wrap of Super 33 with the adhesive facing up and not sticking the connection.  On RF connectors tape will over time get very stuck to the brass connectors.  The back or courtesy wrap prevents this even when using butyl rubber tape.  It allows the wrap to be slit and removed for servicing.  Something that you might find useful if doing the nut and bolt pecker head connections that may face high heat and bake the tape to them.


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## mzayd3 (Aug 29, 2016)

4gsr said:


> Speaking of heat shrink tubing, is there a "industrial strength" tubing that is thicker than the hardware store stuff is?  The stuff seems awful thin for insulation of wires. Or is this normal and safe to use in place of vinyl electrical tape?



Look for double wall heatshrink. It has an adhesive on the inside


Sent from my iPhone using Tapatalk


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## RJSakowski (Aug 29, 2016)

All good advice.   

One bit that I would add is that after wrapping with tape, I will slide a heat shrink collar over the end of the tape wrap to keep it from unraveling.  If the wire are too big for me to use heat shrink I will do what the automotive industry used to do with wrap: tuck the end of the tap underneath the final wrap and pull it tight.  This locks the end in, preventing unraveling.


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