Locomotive Cable for General Wiring

Status
Not open for further replies.
sandsnow

sandsnow

Senior Member
Location
Southern California
When asked about this my first response was no, not unless you can show me it's a type recognized by the NEC. Well the contractor came up with the info. UL listed as RHH/RHW-2. Here's a link to their site. Coleman Cable

Ok, good to go per the NEC, so far

As it turns out there was a kink in the works. Coleman uses an odd sizing on their larger cables. Instead of 500 MCM, they have 535 MCM.

In conversations with the contractor and engineer I told them we would have to go with the 500 MCM ampacity in 310.16 or the engineer could use 310.15(C) engineering supervision to calculate the ampacity since logic dictates it would be a touch above 380 amps at 75 deg. C

Anybody else run across this type of conductor?? He wants to use it because of ease in bending where wiring a large transformer. That's great but he still has to comply with 314.28 and 312.6 in the transformer

Any comments from engineers regarding engineering supervision??
What type of results will he get from that formula?? Conservative or liberal ampacities or just in line comparable with the NEC??

Or am I way off base and missed something obvious here?

Thanks
 
Re: Locomotive Cable for General Wiring

We have used similar cables for connections to strings of storage batteries for UPS systems.

I just found a sample piece in my shop. It has this information on it:

Essex Royal 535.3 MCM (1325#24) RHW-2 600V (UL) E1139RI

Is seems that this cable contains 1325 strands of #24 gauge CU which makes it very flexible. My one concern would be the type of terminations that are used. If I remember correctly we used a special INDENTER HY-PRESS irreversible compression lug. I'm unsure if a standard mechanical lug is designed for the very fine stranding.
 
Re: Locomotive Cable for General Wiring

Using the equations requires attention to details and usually more data than is available, such as the thermal resistivity of the cable insulation and the conduit, or the ambient temperature in the area including the mutual heating effect of other conductors and conduits. I recommend using the 500 MCM rating.

I have had problems getting good terminations with locomotive cable. The many fine strands did not compress well in crimp connectors and would slide out of bolted connectors. Try to find a lug that is listed for use with locomotive cable.
 
Re: Locomotive Cable for General Wiring

I believe that railroad cable is not permitted for building type installations, but it is permitted for equipment installations, such as the equipment listed in the Coleman site.
As has been pointed out by Bob, the reason is the terminating issue with this type of conductor. Take a look at Table 8 in Chapter 9 and you will see that the number of strands (for the same size conductor)is significantly less than in the locomotive cable and the terminations in our line of work are not designed for that many strands - which could lead to failure at those terminations.

[ November 01, 2005, 08:51 PM: Message edited by: pierre ]
 
Re: Locomotive Cable for General Wiring

People like T&B, etc., make crimp lugs that are designed for "DLO cable".

262,313,535,646 kcmil, etc.
 
Re: Locomotive Cable for General Wiring

We've used it quite a lot with the RHH/RHW-2 listing. It was for tight bending areas.
I used the 500 kCMIL ratings from 300.16 to avoid being controversial with the AHJ or installers. There are no code requirements that I'm familiar with, that identify the max or min number of strands in a conductor, so stranding shouldn't limit it's use.
 
Re: Locomotive Cable for General Wiring

Ron
I always respect your responses, as you seem to have a very good grip on the topics you tackle. I would be interested as to UL's response to this one though. I vaguely remember something about this... my mind is not as sharp as it used to be :)
 
Re: Locomotive Cable for General Wiring

Agree with Ron. I have used a lot of the RHH/RHW-2 flex cable in DC plant design. In fact it is the standard used for all such applications in the telecom sector. I have also specified its use where tight bend radius or extreme vibration would be encountered.

As noted a 500 is actually 535, but as long as you use 310.16 there should be problems with inspectors.

The only implication is termination. IMO the only way is to use UL compression terminations. We pretty much specify either T&B or Burndy color coded series with matched dies that clearly imprint the die code.

As long as you can bear the expense of the cable, higher installation cost, and the larger cable insulation diameter, I cannot think of any reason to prohibit it's use as long as it bears the listing requirements.
 
Re: Locomotive Cable for General Wiring

Originally posted by kiloamp7:
People like T&B, etc., make crimp lugs that are designed for "DLO cable".

262,313,535,646 kcmil, etc.
Click to expand...
T&B and Burndy both make terminals for the cable. Trick is to have the right tool$ and die$ to handle it.
 
Re: Locomotive Cable for General Wiring

Thank for the info on the terminals. I will pass that on to the contractor.

I tried doing some searching for lug types on both Burndy and T&B's website. The only thing I found was traction locomotive terminals on T&B's website. Is that what you guys were talking about? I'd like to be able to point the contractor in the right direction.

As far as table 8 goes Pierre, Note 1 seems to take into account conductors may have different stranding types.

thanks again
 
Re: Locomotive Cable for General Wiring

Yes, the problem with terminating fine stranded wire is often overlooked. An overhead crane manufacturer as well as a drives manufacturer customer of mine both used hypalon 105degC,600v wire in their control cabinets. The drives manufacturer had termination failures when terminating onto my breakers burning up the terminal resulting in arcing to ground and them ohase to phase. I still keep one of the 250a frame breakers as an example for those who would like to use hypalon cable. While helping the overhead crane manufacture change a breaker I noted their use of hypalon also. It was easy to show them that, even when the terminal was torqued to specification, that the inner strands were still noticeably very loose as illustrated when the cable was wiggle back and forth. The heating and cooling that occurs most likely will cause the termination to loosen to the point of failure.
Because my engineers could not give me a direct answer for this application, it was not taught nor were there any application bulletins on the subject I started to look into the evolution of wires and terminals which led back to the terminal manufacturer, such as Ilsco, themselves and UL486. UL486 appears to be the mother load of terminal listing. Very basically to be listed the terminal must pass a pull test after specific assembly specifications were followed, such as torque and wire size and type of wire as will as a temperature rise test when loaded. Then the breaker manufacture applies this terminal to the breaker fastening the terminal to the breaker at a specific torque value installing rated cable and running a temperature rise test on the breaker and the termination assembly, UL489.
What is not made very plain is the type of cable that is listed to be used with the terminal. There is no documentation that is easy to access that explains that the fine stranded cables, such as locomotive and Hypalon, are not included to the listing for the UL486 terminals used on breakers of control for example. When someone asks for documentation why not it's very hard to provide them. You can say that you are not supposed to but the problem when someone asked where it says that you can't.
Then, you advise them the crimp on ring tongue terminal must be used which creates a another set of issues such as does the breaker manufacture have a listing which allows an termination method other than its standard terminals. It must be remembered that the temperature rise of the breaker, control component,or similar device is influenced by the method of terminations and cable. Even the magnetic properties of a common grade 5 steel bolt can add to the heating of the termination when used to attach a crimp type ring tongue terminal because of eddy currents induced into the fastener due to current flow. One can't forget that steel that has magnetic properties can get very hot as a result of alternating. current flow
 
Re: Locomotive Cable for General Wiring

templdl
Interesting background. I looked in the UL guide info and it was sol or stranded or both for lug rating. Nothing about fine stranded conductors.

It would seem you could use a compression adapter like they use for aluminum conductors. I can't think of the proper name at the moment. It has a pin to go under the screw lug.

pierre
I'll be around tomorrow and then won't be back until Monday
thanks
 
Re: Locomotive Cable for General Wiring

I am going to try to steer you to a web page where you can select a Burndy Terminals. I tried to use URL code for a link, but I cannot make it work. Anyway first go to:
http://www.fciconnect.com/
>"FIND YOUR CONNECTOR SOLUTION"
>CATALOG click "SEARCH PRODUCT TYPE BY PICTURE"
>Scroll down toward the bottom and click on "COMPRESSION CONECTORS"
>"MEDIUM AND LARGE TERMINALS"
>"TIN PLATED COPPER TERMINALS"
> Check the "US" > SEARCH

Once there it is very easy to find what you want. Class B, C, G, H, and I stranding all use the same terminals up to 250 MCM. After that flex types use special lugs which will be very easy to locate.

Hope this helps. If some one can post a URL link, knock yourself out, I tried, I failed.
 
Status
Not open for further replies.
Top