Proper motor terminations, split bolts? 200HP/480vac/3-phase

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emiller233

Senior Member
Location
pittsburgh, pa
all,
we are having an internal debate about the proper way of terminating some 350KCMIL wires for a 200HP motor (480VAC, 3-phase). I've never wired a motor this large personally so i don't know what is right or wrong here...

so far, the majority is saying to use split bolts for the connections and tape them up.

if not split bolts, what is the proper connection method?
 
kwired

kwired

Electron manager
Location
NE Nebraska
emiller233 said:
all,
we are having an internal debate about the proper way of terminating some 350KCMIL wires for a 200HP motor (480VAC, 3-phase). I've never wired a motor this large personally so i don't know what is right or wrong here...

so far, the majority is saying to use split bolts for the connections and tape them up.

if not split bolts, what is the proper connection method?
Click to expand...
Split bolts work, some just think they cry hack.

Most split bolts are only rated for two conductors - so if you need multiple leads plus the supply conductor in one connector that could be an issue.
 
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emiller233

Senior Member
Location
pittsburgh, pa
the shop said they cant crimp wires that large, thats why they're looking at alternatives. i will take this PDF down and show them these Clear Unitap and see what they think :thumbsup:
 
Jraef

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
Are you guessing that your motor has leads only, or do you already know for sure? Many motors that size now give you studs on a pad or a terminal block for terminations. Even with leads only, they will often provide you with pre-crimped ring lugs.

This is a picture of a 200HP hooked up on a test bench, but it shows the terminal box open.
hqdefault.jpg
 
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emiller233

Senior Member
Location
pittsburgh, pa
I'm not sure yet, I am waiting for the MFGR (Worldwide) to call me back. Multiple voicemails with no call back
So yes, at this point i am guessing that it has leads...
 
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emiller233

Senior Member
Location
pittsburgh, pa
i finally got in touch with someone and they did confirm it is dual voltage wire leads with #3awg coming out of it.

we were planning on running 350KCMIL wire to this motor, does that sound reasonable (got it off of one of our quick reference Motor slide charts)

I am going to get the Burndy BIT350 quoted, this looks like the perfect solution!

https://ecat.burndy.com/Comergent/e...DetailMob&showAddButton=true&productID=BIT350

CUnitap2PortSS_Photo_ColorRGB.jpg
 
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Jraef

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
Don’t be freaked out by the use of smaller conductors inside of the motor compared to field wiring requirements. Different issues.

Those Burdy connected are a good choice. Just be careful about letting them rub up against the walls of the peckerhead, the vibration will wear through the insulation and create a ground fault.
 
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emiller233

Senior Member
Location
pittsburgh, pa
Joe Villani said:
Typically the motor leads I see are finely stranded wire and I would double check this connector is suitable for use finely stranded conductors.

See 110.14 in the NEC.

http://www.nsiindustries.com/catalo...y-insulated-connectors-for-fine-stranded-wire


https://commerce.ilsco.com/e2wShopp...k=2100001183:3100012208:3100012314:3100012756
Click to expand...


Just an FYI,
I got in touch with Burndy today, and they recommended i use their Burndy # BIT350FX for this application. I mentioned the fine strand wire/sizes

http://ecat.burndy.com/Comergent/en...geType=catProductDetailMob&showAddButton=true
 
Jraef

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
emiller233 said:
Just an FYI,
I got in touch with Burndy today, and they recommended i use their Burndy # BIT350FX for this application. I mentioned the fine strand wire/sizes

http://ecat.burndy.com/Comergent/en...geType=catProductDetailMob&showAddButton=true
Click to expand...
Just for future reference, the part of their specs that is telling you it is suitable for the high strand count is this:
ClassG,H,I,K
Click to expand...
Standard "building wire" like THHN is usually Class B stranding, "extra flexible THHN is Class C, so standard mechanical lugs are usually OK for those. "DLO" cable is usually Class K and motor lead wire is typically Class I.
 
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emiller233

Senior Member
Location
pittsburgh, pa
Jraef said:
Just for future reference, the part of their specs that is telling you it is suitable for the high strand count is this:

Standard "building wire" like THHN is usually Class B stranding, "extra flexible THHN is Class C, so standard mechanical lugs are usually OK for those. "DLO" cable is usually Class K and motor lead wire is typically Class I.
Click to expand...


Great info!!
Thank you!
Learn something new everyday:thumbsup:
 
Julius Right

Julius Right

Senior Member
Occupation
Electrical Engineer Power Station Physical Design Retired
I ordered once [since I was Power Station designer only] different sizes Burndy Unitaps .It is a bit complicate as there are a lot of details but Burndy material it is very good stuff. I ordered thousand of
details as lugs, presses and other and no complain was ever registered.
 
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Shortcircuit79

Member
Location
WV
Cleartap issues

Cleartap issues

You should be aware the there are specific compression taps designed for motor connections. The common variety are not intended for the fine flexible motor conductors and will eventually loosen up due to heat and fail.
sorry this is late did not see above threads
 
petersonra

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
there are a bunch of ways to do this, as long as they are done correctly all of them work and as far as I am concerned if it works and is safe, I just don't care much.

people like to whine about how hard it is to replace a motor that has been wired up with bolts and taped over. so what? it is not like you do it on any regular basis. most motors will outlast most electricians.
 
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