Is welding cable suitable for battery systems?

[sdold]

At my job,the installers have been using EPDM-jacketed 4/0 welding cable in battery plant wiring. The flexibility makes it easier on the installers. I was never much involved with that, but I was recently asked to give an opinion on whether or not they should order more of this type of cable for this purpose. I was given a cut sheet that does not mention RHH, RHW, etc. Only that it is EPDM jacketed. I don't have a sample to look for markings.

Looking through the NEC, I can't find a mention of this type of cable for anything other than welding. So I have a couple of questions:

1. I'm assuming this cable is probably not suitable for these DC plants, am I right?

2. I see some other welding cable that is cross listed as RHH/RHW. Would this be OK?

The main thing I'm wondering is if the cable has (for example) the RHH mark, does 310.13 imply that it's OK for this? .

Thanks!

Steve

[SunEagle]

I have seen the use of EPDM welding cable used for larger battery banks so I do not beileve there is a code issue if they are properly terminated and protected from physical damage.

I believe a company called Waytec makes battery and welding cables using the EPDM insulation with red and black coloring.

[adoublee]

I don't think the issue is with the cable, it's with the connectors/terminals it lands in. I think this can ends up being problematic for welding cable or other finely stranded cable at the equipment it connects to.

NEC 110.14 - Connectors and terminals for conductors more finely stranded than Class B and Class C stranding as shown in Chapter 9, Table 10, shall be identified for the specific conductor class or classes.

[Sunking]

Absolutely Steve and is pretty much default choice in Telecom. To be code compliant it needs to be Dual Rated such as DLO/RHH-RHW-2. As stated the compression terminals are different than those used for Class B Stranding. They have longer barrels needing 2 to 4 crimps, and slightly smaller for AWG because the fine stranding make for smaller diameter. Use Lead Plated without Inspection Holes on Battery Term Post.

The main reason to use it is much easier to bend and flex in tight spots. Extra care must be exercised when terminating the cable. Additionally from a technical POV has much lower Impedance to high frequencies due to the increased surface area for SKIN EFFECT. It is also used in Hard Use and Vibration like machinery where the cable physically is exposed to movement, abrasion, and vibration. The copper is softer and wil not break like harder annealed copper from stress and fatigued.

In short it is superior and why it is required to be used in Marine, Automotive, and Aircraft industries. It can most certainly be used as building power and lighting cable if you can afford it. Code just requires it to be rated for such like RHH RHW, or XHHW-2. In telecom we use a designation LS aka Low Smoke version like XHHW-2 LS which means a crossed linked polymer insulation, rated for high heat, wet, and low smoke insulation. Ever read about th eTelco Office fire in Chicago decades ago that shut down Chicago Telephone service for days? It was that fire that brought about Low Smoke insulation.

The smoke from sulfur based plastic compounds was what destroyed the equipment, not the fire itself. The smoke mixed with water = Sulfuric Acid and ate the equipment up. That is back when Switches were mechanical relay known as Cross-Bar and Rotary offices. It filled multistory buildings full of equipment.

T&B and Burndy make the connectors, and I can give you a list of cables. You know how to find me.

Hope that helps you friend. Ring my bell anytime, you got the number and address.

[sdold]

Thanks all for the comments. Can I assume that it's code-compliant if it's marked with a designator in the 310.13 list, and that it's not code-compliant if it's not?

I didn't know about the lower impedance. Maybe it would be good for bonding the coax entry plate to the ground electrodes. For awhile we were laying out scraps of waveguide on the warehouse floor and rolling the forklift over them to make flat conductors for that bonding, but we stopped for some reason.

[Sunking]

Thanks all for the comments. Can I assume that it's code-compliant if it's marked with a designator in the 310.13 list, and that it's not code-compliant if it's not?

Yes sir that and Low voltage 300 volt cables in article 7xx something. To lazy to look right now.

I didn't know about the lower impedance. Maybe it would be good for bonding the coax entry plate to the ground electrodes. For awhile we were laying out scraps of waveguide on the warehouse floor and rolling the forklift over them to make flat conductors for that bonding, but we stopped for some reason.

Please stop.

Preference order:

Andrew Braided Bonding Kits. Comes with Braid, hardware, and water seal.
Claas H Super Flex tinned 4 AWG like we are talking about.
Last resort Class B stranded 4 AWG RHH/RHW-2. OK for inside to bond SPD to Hatch Plate Ground Buss.

FWIW the impedance is not that big of a deal. More aimed at 400 Hz power. At lightning frequency and rise times is meaningless. That is why the GEC's bonding jumpers are Solid, Tinned Copper, and Bare because thermal capacity is what you are looking for, not impedance. Tinned for corrosion resistance with acidic soils. Specify tinned conductor for all uses. Keeps green crusty monsters away. Lead plated terminals around batteries.

I am telling you to many secrets of the trade.

[solarix]

Technically, the Code is not applicable for systems less than 50V which is why off-grid battery systems are 48V (nominal) or less. My understanding is that terminal lugs for large wire like 2/0 is not rated for fine stranded wire like welding cable. Our practice is to go ahead and use welding wire and crimp the terminals like normal, but also solder and heat shrink them. Large strand 2/0 wire is just impossible to work around battery terminals with.

[Sunking]

Technically, the Code is not applicable for systems less than 50V.

That is not a True Statement. If less than 50 volts the code allows you some leniencies with respect to grounding a system,

As for cable terminals, terminals for Fine Stranded wire and cable are of a different design using a flared barrel often longer barrels with slightly smaller barrel diameter. In Telecom and many larger solar applications 2/0 would be the smallest wire to ever use. Multiple parallel 750 MCM is snot uncommon, and Class H and higher strands are extremely easy to use and bend. In any code application to run parallel conductor requires using 1/0 or larger.

I think the issue here is terminology. Welding cable has no UL definition. Welding cable I am familiar with is UL DLO aka Diesel Locomotive using CPE (chlorinated polyethylene) insulation which produces an acrid smoke when burned. Thus why telecom only uses LS version with a Cross Linked or Neoprene smokeless insulation. To be used in any NEC application a welding cable must be Dual Rated no ifs ands or buts. No big deal because just about all of it is dual rated and comes in low Voltage 300, 600, 1000, and 2000 volts. The low voltage stuff you can use on 50 volts and less is seldom used unless you find a dealer stuck with it offering a huge discount because normally it is higher priced then 600 volts because demand is so low and usually a special order.

Back to terminals and this may help. Here is T&B Catalog. Scroll down to pages with compression terminals like pages B-9 to B-20 for short barrel lugs and note the odd cable sizes with WELD or odd sizes like 61/24, 422 KCM All those are for Fine Stranded cable. Scroll down further to page B-24 to 32 are all long barrel and most of them are specifically fine stranded as you will see. Example on page B-24 1/0 is 225/24 90.8 Kcmil. That is for 1/0 Flex using 225 strands or 24 AWG wire and 90.8 Kcmil. You cannot put that lug on a Class B strand 1/0 AWG cable as it would be to small. Likewise you would not use a 1/0 terminal made for Class B stranding on a 1/0 Flex cable because it is to large. Keep scrolling and you will find the Bell or Flared terminals specifically for fine stranded cable.

[sdold]

Thanks for the link and the explanation. Are the flared terminals only needed if they are going to flex, or should we be using them on the batteries too?

[Mike90250]

........ For awhile we were laying out scraps of waveguide on the warehouse floor and rolling the forklift over them to make flat conductors for that bonding, but we stopped for some reason.

Ha ! silver plated waveguide at $30 per foot vs heavy copper 1" plumbing pipe at $2 foot. What a waste of expensive waveguide. And the flanges on either end - Arghhh!

[Mike90250]

I heard Machine Tool Cable (MTC) was allowed, but any fine strand cables need matching fine strand lugs

[sdold]

I think the waveguide was about $5 a foot. It's not a waste,it would just go to the recycler anyway. We always add 10 or 20 extra feet when we send out a reel of waveguide for a job because for a 100 or 150 foot run, it's not much more and it would be a disaster for the crew to come up short. It's not silver plated and no flanges used.

[Sunking]

Thanks for the link and the explanation. Are the flared terminals only needed if they are going to flex, or should we be using them on the batteries too?

No strictly for machinery where the cable need to move like a crane arm or tract crawlers. Or on a Locomotive where there is a lot of vibration. The rounded edges will have less abrasion than a 90 degree angle and allow the cable some bending radius.

The issue you have to concern yourself as the engineer who specs the connectors need to specify the right connectors for a Flexible cable strand. Example a 2/0 Flexible cable is physically smaller in diameter than Class B because there is less air space between conductors so the cable is more compact. If you used a standard 2/0 terminal would be to big. Consequently if you used a 2/0 terminal made for flexible strands on standard Class B stranding the Terminal would be to small forcing the Sparky to cut off strands to make it fit. If he is a good Sparky will JIM and educate you with Change Order costing you more money. Lord knows I have been there and done that. That is how we learn. School doe snot teach you squat about the real world.

Steve check out Cobra Wire and Cable product lines like TelcoFlex, Cop-Flex, Battery, X-Flex, and X-Flex 150. They are all flexible cable from Class H to Class M stranding. Southwire is a distributor. All of the Cobra stuff is multi-rated RHH/RHW-2 LS and used by most telcos. Anixter is another great source of Telco grade power cable. They even have the stuff I like best with the Cotton Braided jacket required in a CA Central Offices. The Cotton Braid can be laced down wiht 12-ply waxed power cord to cable racks without Fish Paper. Keeps everything in place without cutting into the insulation when the earth decides to move about out there and shake things up. Just remember to specify put Earthquake "S" waterfall off racks so you have slack for movement.

[sdold]

Steve check out Cobra Wire and Cable product lines like TelcoFlex, Cop-Flex, Battery, X-Flex, and X-Flex 150.

Thanks, I appreciate the help. I'll see about getting some samples and lugs to try, I also appreciate the info on the lug sizes, you must have seen a lot of wrong lugs installed.

[Sunking]

Thanks, I appreciate the help. I'll see about getting some samples and lugs to try,

Any time Steve. You know how to find me.