INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

Wire type suggestion for a machine tool install.

Wire type suggestion for a machine tool install.

(OP)
I recently helped a guy with a rotary converter problem and found the wire he had installed to be the worst wire I'd ever worked with. It was so frikken stiff it was absolutely miserable to use. It was some gawd awful crap he'd bought at Home Despot. I suspect it was Chinese stuff that they didn't bother annealing after the last draw or something. It was 2AWG and had about 5 strands. The guy had actually had to make tools to bend it so he could get it to the lugs in panels made for considerably bigger wire than 2AWG. For the work I helped him with that wire literally added 3 hours to a 2 hour job. I never want to see or deal with that again.

He now needs to install a second machine and is asking me what wire to use "this time" not wanting to fight with that stuff either. We're not looking for welding cable flexible but can anyone suggest something between this 'iron bar' crap and welding cable? This is for 240V service. NEC land.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Wire type suggestion for a machine tool install.

Keith,
Sounds as though he bought SEU (Service Entrance Underground) cable which, because it rarely needs to bend, has a low strand count (should be 7 strands for #2) and yes, that's stiff. That SimPull THHN would be 19 strands, that's what you want (or any other brand as long as it's the higher strand count). HD is not likely to carry that, you'll have to get some from an industrial supplier.

A warning on DLO cable or Welding cable: most mechanical lugs are NOT rated to be used on that K class stranding and higher, you must use crimp lugs and only those specifically made for that.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

RE: Wire type suggestion for a machine tool install.

How about MTW (Machine Tool Wire)?

Here is a link to a place I use sometimes to buy smaller quantities of different wire https://www.wireandcableyourway.com/Copper-Buildin...

Not sure where you are but likely a local full service electrical supply house will also be able to get MTW in #2AWG for you as well.

MikeL.

RE: Wire type suggestion for a machine tool install.

(OP)
Guys, many thanks! My hands feel better already! Jeff thanks too for the mini-education, I wondered.smile

Keith Cress
kcress - http://www.flaminsystems.com

RE: Wire type suggestion for a machine tool install.

(OP)
Followup. I see that, as an example, MTW AWG2 has 650 strands!! - probably crazy soft and pliable but does it have the lug issue Jeff's mentioning? That would be in regards to standard panel breakers and typical machine tool disconnect cage clamps.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Wire type suggestion for a machine tool install.

(OP)
Hunting down what Jeff mentioned about "K" wire I found this useful link:
https://www.iewc.com/resources/technical-guide/stranding-classes

Does MTW mean "M" series stranding? That would be considerably finer wires than even "K".

Ah, further research shows that class "K" is 600+ strands so the MTW certainly falls in that realm. Ack! Now I have to try to figure out if the various clamp connections will be acceptable.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Wire type suggestion for a machine tool install.

There are two solutions to using fine strand wire directly with mechanical connections, either ferrules or wrap around sleeves.

http://www2.schneider-electric.com/resources/sites... talks about this situation.

For years we used DLRO, DLO and weld cable for rental power systems and camlock connections, we used prepackaged cut copper strips to wrap around the wire strands before inserting into the connector, the sleeve keeps the strands together and allows for a good connection. CamLock part numbers for those are A100400-1 (or -3 or -4) and here is an assembly instruction, http://www.cooperindustries.com/content/dam/public...

I have also used ferrule sleeves like these in many applications,

https://burndy.com/docs/default-source/cutsheets/b...


Burndy (and others I'm sure but I always use Burndy) make crimp on pin terminals that have been specified on a number of jobs I have worked on over the years,
http://ecat.burndy.com/Comergent/burndy/cat/603106

There are also these, https://lugsdirect.com/Flex-Cable-Wire-Adapters.ht... I haven't used them yet but I have a job coming up where they were specified so that is what is getting installed, but they look well made and apparently the local AHJ was good with them.

Hope that helps, MikeL.

RE: Wire type suggestion for a machine tool install.

The stranding class and the wire type are not universally joined at the hip; you can get MTW that is 19 strand, or MTW with Class K stranding, it's up to you. I was just making you aware of the potential drawbacks of using too high of a strand count.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

RE: Wire type suggestion for a machine tool install.

I would stick with 19 strand or at the most 37 strand.
The Canadian Electrical Code has tables listing the applications that the various wire designations are approved for.
There must be something similar in the NEC.
What is good for a rental generator application may not be acceptable for a permanent installation under the NEC.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Wire type suggestion for a machine tool install.

(OP)
Thanks again!

MikeL; I find it interesting that DLO cable has about 150 strands but MTW can have 600+. I'd have guessed moving train-like stuff would benefit from more flexible cable but I guess the wire running down a moving cable guide to a Z-Axis could greatly trump the required train flexibility.

Thanks for the ferrule/wrap info!

Jeff; Great.. Yet more exceptions. LOL MTW 600+: MTW 19 strand! $^%@@&*#

Bill; I think that's what we'll do (19-strand THHN) as that's probably easily found in town at the electrical supply houses.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Wire type suggestion for a machine tool install.

DLO is not only flexible, it is tough.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Wire type suggestion for a machine tool install.

MTW is the correct wire for machine hookup. Watch out, most THHN (the stiff crap) is dual rated MTW. It's not the same as real MTW wire which has thick PVC jacket, higher strand count, and sometimes even tin plated conductors. I find wire that meets MIL-76D Type MW to be quite sufficient for all of my marine hook-up applications.

Don't use SO cable, either. The neoprene insulation breaks down rapidly in hot junction boxes or in the presence of ozone from contactors. Marine shipboard cable is similar to plenum duty cable and lasts a long time.

Finally, it's not to your benefit to oversize conductors. I know too many people that try to wire their home outlets with 10ga because it must be better. It puts so much strain on terminals and can't be stuffed in boxes properly so it ends up getting pinched or pierced by screws.

RE: Wire type suggestion for a machine tool install.

I agree, plain MTW is easier to work with in a panel than THHN/MTW. The THHN has a nylon (the "N" in the name) outer jacket to protect it from abrasion when pulling through conduit, that makes it difficult to work with in a panel and it's unnecessary there.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

RE: Wire type suggestion for a machine tool install.

Try a crescent wrench with a round hole in the handle. One or two make serviceable cable benders. They will mark the cable so try it and see if you can live with the marks. It may help to tape the hole or use pieces of insulation to cushion the edges of the hole in the wrench.
If it is not possible to work in the plane of the bend such as some bends inside the panel, use the wrench at 90 degrees to the plane of the bend and grip the jaws of the wrench with another wrench to twist it.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Wire type suggestion for a machine tool install.

Thank you all for an informative discussion.

Muthu
www.edison.co.in

RE: Wire type suggestion for a machine tool install.

If this is the wire being pulled through a conduit from the distribution panel to machine then the better quality THHN with a high enough strand count that it can be bent is all you need. 2AWG isn't heavy enough to make bending it such an issue that other wire types like MTW or TEW need to be used.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close