5 Tips to Help Keep Your BNC Cables Working

One cable you're likely to encounter on set is the BNC cable. In my experience, BNC cables are highly fickle and, if not treated right, can easily stop working. So here best practices to keep in mind to help you make your BNC cables last -- at least until you have to return them!

Learning the over/under method of wrapping cables is only half the battle — the other half is trying to keep them working for as long as possible.

One cable you’re likely to encounter on set is the BNC cable, used mainly for video village and monitoring purposes. It’s common to rent out hundreds of feet worth of these cables and run circles constantly keeping track of them.

In my experience, BNC cables are highly fickle and, if not treated right, can easily stop working. So here are a few best practices’ guidelines to keep in mind to help you make your BNC cables last — at least until you have to return them!

1. Loop the BNC Cables on the Camera

Proper wrapping of the cables is important, but you also want to make sure the cables aren’t under any stress in other situations.

The locking mechanism these cables use means they won’t just pop out, so pulling on them puts tremendous stress on the cable itself and whatever it’s connected to. When they’re connected to the camera, try and loop the BNC cable around some piece of the camera (use Velcro if you have to) to keep the cable from being tugged directly on the connection itself.

This loop method also affords you a few inches of leeway if you start to run out of slack.

2. Always Have Somebody to Wrangle

On moving camera shots, whether handheld or on a dolly, have somebody who follows behind the camera to wrangle the cable. Most of the time I ask the 2nd Assistant Camera (AC) to wrangle after they are done slating, but if that isn’t possible, borrow a production assistant (PA) for whichever shots you need.

Without somebody wrangling, you present a safety hazard, and also have people constantly walking on the cable and equipment possibly resting on it. All of that weight on the cable — especially in the wrong way — can compromise its build and cause it to start acting up.

If you absolutely do not have anybody who can wrangle the cable, throw it over your own shoulder if on handheld or use camera tape to attach it on the dolly in a way where it hangs off the side instead of the back.

3. Keep the Center Pin Straight

Grab one end of a BNC cable and stare directly into it and you’ll see the eyes of God a single pin sticking straight up. If you think this sight looks familiar, it’s because the single-pin structure is the same as the cables you use to hook up your cable box, just with a different connector.

That one pin used to establish the communication between the cable and the device you attach it to. Because of that, it’s a pretty big deal.

If you keep staring, you’ll notice that there is almost nothing else around this pin which means it’s very susceptible to being bent. You can avoid that happening by never forcing the cable into anything and also being sure you place it in straight.

When the cable does become bent because the Camera PA got too hasty with it, use a pair of needle-nose pliers to delicately straighten it out.

4. Lay Them Flat During Storage

Each cable has a natural curve and bend to it and to do anything other than coil it along this bend is to dramatically shorten the lifespan of the cable. Even though they can twist, turn, twirl, and twine, those moments should only be temporary.

When you are storing the cables away, let them hang loose or lay flat on top of each other in a natural curve.

And don’t stack heavy cases or gear on them in a way where it could puncture the cable and damage the internal wiring.

5. Prepare with BNC backups

When assembling your camera package (whether by rental or purchase), always get double the length of BNC cable that you need. If possible, get a backup cable of each length (i.e. two 15 ft cables, two 50 ft, etc.).

Barrel connectors or “bridges” are also crucial to have backups of in your toolkit. Often it is the BNC barrels that go bad and not the cable itself. If you don’t own any — or want more for safety — many rental houses will gladly supply you with a few if you ask.

BNC cables are notorious for turning up at the end of the shoot dead and sometimes it’s an accident, other times it’s out of ignorance. But I promise if you adhere to these 5 tips that you’ll lengthen the timespan you’re able to keep a BNC cable operational.

  • http://www.facebook.com/allen.p.kelly Allen Patrick Kelly

    Also before you start running cable everywhere, get a cable checker to test for continuity and shorts on each line. Testers can be found online for $25-45, but the cost/time savings are immeasurable!

    • http://www.theblackandblue.com/ Evan

      Usually I test them all during camera prep and assume the rental house does that as well, but for $25 – 45 it might be worth it to have a checker in a pinch. Thanks for the heads up on that Allen!

      Where would you get something like that?

  • Adam Richlin

    Every once in a while I get a gung-ho PA who wants to help us camera guys. “Ok, wrap that feed of BNC for me.” 

    I learned quickly to ask if they know *how* to wrap BNC before letting them. One gig I was on, the PA did the construction worker’s around-the-arm technique and ripped the tips off two sequential sections of cable :/

     Which brings me to Evan’s point #5! Haha.

    • http://www.theblackandblue.com/ Evan

      Ah the construction worker around-the-arm is the worst! I used to do audio stuff in high school and when we broke down stages, parents would help us clean up. I got used to telling them to just leave the cable… I saw too many of them doing that!

      I do whaty ou do too, Adam, and make sure the PA knows how to do it properly.

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  • http://www.kellyonatangent.wordpress.com KD

    I work in a rental house.  One thing that a lot of people don’t realize is the actual physical limitations of cables.  Running Composite video over 500′ of BNC is possible, but HD-SDI signals are 1500mbps.  That is very high frequency, and requires a quality cable.  The longest you can realistically run a HD-SDI signal on pristine cables is about 300′.  But what people don’t realize is, if somebody rolls a cart over that cable, even though the cable still looks fine externally, the shielding inside might be damaged.  This means that those high frequencies bleed, and your 300′ may drop to 150′ (or less).

    • http://www.theblackandblue.com/ Evan

      Thanks for that information KD. It’s nice to have the numbers to help quantify that!

  • http://www.michaelaangelique.com Michaela Angelique

    I have a question.

    Last time I was shooting provided with new BNC cable. it’s pretty hard to wrangle though, it’s not soft to wrangle. I hope I did the right thing, I checked your video from youtube last time how to wrangle a cable for video village, but that cable is very easy to wrangle, and I’ve always had that cable. But I was just done with another shoot, the cable that I just had, it’s very firm, everytime I wrangled, I felt it’s twisted. Have u ever had this texture of cable ? I was wondering how you managed to take care of it. Thanks.

    • http://www.theblackandblue.com/ Evan

      I have dealt with cable like that. You sort of have to force it and it really never lies flat. Cable like that is annoying and usually cheap.

  • Blah

    I like to cut the ends off and give them as wrap gifts to various people in our department.  Specifically the DIT and the Utility.  

    • http://www.theblackandblue.com/ Evan

      Haha! Very cool idea :) 

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  • Wis S.

    I always ask for an extra ultra flexible BNC (or composite intended then add adapters) that I connect between the main camera feed cable and director’s monitor, especially on university or indie shoots. I keep a short one in my gear bag.
    I do this because of young directors’ frustrating tendency of grabbing the monitor (and never letting it go), walking around with it on set (think wireless), and putting it down onto the connectors side and stressing them, ultimately leading to cable or monitor input damage.
    Thanks to its flexibility I can loop the extra cable somewhere on the monitor and not worry about cable rape during transports, thus protecting both the main cable and connectors. And if it does end up being broken, at least it was a cheap cable and we’ll still be left with the main one until it’s fixed.
    I’m aware of the potential quality loss, but it’s generally negligible because the main cable would be under 10 meters most of the time. And it’s worth the cable/monitor protecting on budget shoots!

    • http://www.theblackandblue.com/ Evan

      Not a bad idea Wis! Thanks for sharing it with us. You always have to gameplan for people who don’t respect cables as well as the rest of us.

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  • Stephen S.

    I carry a small bag full over various BNC connectors, but my favorite is the right angle connector. I leave one on our EPIC at all times since its recessed so far under the camera, and often on my monitor as well. Helps to keep stress off the terminal end, and often redirects the whole coil to a more natural, out of the way position.

    • http://www.theblackandblue.com/ Evan

      Those little buggers are crucial for the exact situation you just described (among other things). I also like to have a 90 degree adapter for HDMI cables. It was more handy back when the RED One was still at the top, but it has its purposes every now and then.

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