What kind of cams are these?

[derekleffew]

From PLSN | When Welding, Weld; When Not Welding, Don't Weld :

But after the 1984 Olympics in Los Angeles, when a production company asked the City of Los Angeles to allow the use of welding cable and Tweeco [sic] connectors, they said “No,” and its use was “outlawed” by the NEC. Most of us got the message and moved on to SC-type feeder cable, which is commonly called “entertainment,” cable and the use of welding cable was largely discontinued.

Of course we didn't have the Internet back then, and news traveled slowly to the midwest. As late as 1988 (that I know of) many were still using Twecos and welding cable as feeder.

 

[cdub260]

NEC 2011 Article 520.53(H)(1) also applies.

(1) General. The supply to a portable switchboard shall be by means of listed extra-hard usage cords or cables. The supply cords or cable shall terminate within the switchboard enclosure, in an externally operable fused master switch or circuit breaker or in a connector assembly identified for the purpose. The supply cords or cable (and connector assembly) shall have current ratings not less than the total load connected to the switchboard and shall be protected by overcurrent devices.

Inevitably someone will ask, "But what if I find listed welding cable?"

Even if by some chance you do find listed welding cable, it's listed for welding applications, not for temporary power hook-ups.

One final question for you all.

How is the piece of yellow tape on the tails a code violation? Again, bonus points if you can cite (Yes Derek, I spelled it right this time.) the relevant section of code.

 

[chausman]

How is the piece of yellow tape on the tails a code violation? Again, bonus points if you can cite (Yes Derek, I spelled it right this time.) the relevant section of code.

It's not fire proof/resistant?


Sent from my iPad using Tapatalk

 

[techieman33]

I'm to young to have seen that style of cam I guess. We do have 7 of those dimmer packs in the building though and they have never let us down. 3 that are permanent in our black box and 4 that float around and get hooked up for things like ballets, or in the ballroom, etc. There are also multiple ways to wire them up, we have 220 plugs we can attach, or we can wire them up 3 phase to a distro depending on where we need them and how much power we need.

 

[gafftapegreenia]

Ah, so Tweco and Trico are two VERY different things, but but greatly frowned upon.

 

[dramatech]

Derek,

As I understand it, "W" means that the cable has a much thicker insulation and is good for placement on the ground.

For several years, I worked for a very small company that built ice skating rinks on theatre stages. When I first got there, they were using tweco connectors with welding cable for powering the chilling equipment. I eventually got them to convert to cam-loks with stage and lighting cable.
When doing a rink at the Miami-Dade county fair, we were told that we would have to have "W" cable the next time we came. They were requiring it of all the carnival rides. They quoted, but I am not sure by which authority, that all outdoor cabling used in by carnivals and placed on the ground must be "W" cable.
We built our next three travelling rink units with "W" cable. within our company, we used the "W" to mean weather impervious cable. I'm sure that is not the official designation.
The insulation on the "W" cable is so much thicker than SC cable, that the entry point on the camloks for cable had to be cut for 4/0 when used with 2/0 cable.

While this is not an official explanation that would be given by Steve Terry, it is as I have learned it.

Tom Johnson

 

[STEVETERRY]

Derek,

As I understand it, "W" means that the cable has a much thicker insulation and is good for placement on the ground.

For several years, I worked for a very small company that built ice skating rinks on theatre stages. When I first got there, they were using tweco connectors with welding cable for powering the chilling equipment. I eventually got them to convert to cam-loks with stage and lighting cable.
When doing a rink at the Miami-Dade county fair, we were told that we would have to have "W" cable the next time we came. They were requiring it of all the carnival rides. They quoted, but I am not sure by which authority, that all outdoor cabling used in by carnivals and placed on the ground must be "W" cable.
We built our next three travelling rink units with "W" cable. within our company, we used the "W" to mean weather impervious cable. I'm sure that is not the official designation.
The insulation on the "W" cable is so much thicker than SC cable, that the entry point on the camloks for cable had to be cut for 4/0 when used with 2/0 cable.

While this is not an official explanation that would be given by Steve Terry, it is as I have learned it.

Tom Johnson

There is some confusion here, and no wonder.

"Type W" is a double-jacketed extra-hard usage cable. It is rated 2000 volts, and is oil resistant. It is available from 1-6 conductors and #12AWG to 1000 kcmil. Note that this letter "W" is not a suffix to another type, it is the actual type designation.

Type SC (formerly known as EISL, or Entertainment Industry Stage Lighting Cable) is a single-jacketed extra-hard usage cable. It is available in 1 or more conductors, in sizes from #8AWG to 250 kcmil. It is rated 600 volts.

Neither cable is specifically rated for damp or wet locations or sunlight resistance.

Quite separate from the above, the letter "W" included in other cable types as a suffix to the cable type designation, per note 15 of NEC table 400.4 (for instance in type STOW), indicates suitability for damp or wet locations and sunlight resistance. Therefore, these types are suitable for outdoor applications.

There will be a quiz later.

ST

 

[jstandfast]

I'm almost tempted to ask Derek to date the image. If taken in 1983, then as Mr Terry has pointed out, it was the risks we ran and the current technology at the time, welding cable included. On a different note: am I the only one who thinks the Kellum Grip pictured is just all kinds of wrong in this application ?

 

[derekleffew]

I'm almost tempted to ask Derek to date the image. ...

2011. It's from a current item on a popular online auction site. "Buy it Now" price of $999 (!) and it's missing two fuse holder covers, which renders the item totally inoperable.

Am I the only one who thinks the Kellum Grip pictured is just all kinds of wrong in this application ?

I don't think the Kellems grip is misused, and since any strain-relief was left up to the user (not supplied by the manufacturer), most didn't use anything at all; so I'm happy to see anything there.

 

[jstandfast]

Sadly, I'll bet I've got those fuseholder covers in my workbox somewhere; they were the weak link with those things, great as they were, in terms of shipping, always going astray.............. I think my unease about the kellum grip has to do with the multiple wires involved, isn't the kellum suited to grip one jacket ?

 

[derekleffew]

...Isn't the kellems grip suited to grip [only] one jacket ?

You may be right, but I suspect we've both seen break-outs/break-ins using a basket-weave strain-relief:

(The above pictured conveniently date from approximately the same time as the original dimmer pack, so YMMV.)

And, as I said, anything is better than nothing.

Mr. Terry: Does the NEC or UL Listed have an opinion about using multiple wires/cables within a single basket-weave style grip?

 

[DuckJordan]

You may be right, but I suspect we've both seen break-outs/break-ins using a basket-weave strain-relief:

(The above pictured conveniently date from approximately the same time as the original dimmer pack, so YMMV.)

And, as I said, anything is better than nothing.

Mr. Terry: Does the NEC or UL Listed have an opinion about using multiple wires/cables within a single basket-weave style grip?

I'm not Mr. Terry but I do know that The Sound Reinforcement handbook from Yamaha states you should never accept any equipment with them.

 

[STEVETERRY]

You may be right, but I suspect we've both seen break-outs/break-ins using a basket-weave strain-relief:


Mr. Terry: Does the NEC or UL Listed have an opinion about using multiple wires/cables within a single basket-weave style grip?

Actually, yes. But it goes further than than that.

The Kellems grip on the CD80 pack is known as a "standard" model. This is a single weave grip connected to a device much like a chase nipple with a "notional" rubber dust cover. IMHO is is a piece of junk. Here's why:

1. It has no compression gland to trap the cable in the through-panel fitting. This means that it is only suitable for cables under constant downward pressure to keep the basket grip in gripping mode. In the application of the CD-80 pack, one can push the conductors back through the fitting, compressing the basket weave and rendering the grip useless.

2. This device is only listed for a single cable, and unlike other devices (more below), it won't maintain any compression force on a cable bundle. A wad of gaffers tape would probably be more effective.

The solution is known as a "deluxe strain relief" Kellems grip, and it marries a compression gland and a basket weave grip. See page T60 of attached catalog. This device captures a single cable or bundle of cables under a compression gland. No push-back can occur, the grip operates in any orientation, and a bundle is tightly held in the soft rubber taper grommet. It's the cat's meow.

This is the same type of grip used in a Pyle-National Star-Line multiconnector, shown later is this thread. We used this type of grip for breakouts at Production Arts with great success.

ST

 

[derekleffew]

...but I do know that The Sound Reinforcement Handbook from Yamaha states you should never accept any equipment with them.

Can you quote the exact passage? I do hope you're mistaken, as this would preclude the use of the majority of mic snakes by top manufacturers:

 

[DuckJordan]

Can you quote the exact passage? I do hope you're mistaken, as this would preclude the use of the majority of mic snakes by top manufacturers:

Page 287, Cabling 15.2.4 Strain Relief They have a picture of a stage box with strain relief. "Figure 15-6. Avoid Chinese handcuff type strain relief."

 

[jstandfast]

Spent many a year working a venue populated with pin connector ( and Socopex/Veam added later) drop boxes which had been strain relieved with
standard Kellems grips. Checking the stage of "wiggle through" on the strain reliefs was a standard cyclic maintenance item.........

 

[derekleffew]

Mr. Terry: "'Deluxe strain relief' Kellems grip" for me it is then.
So you don't think the dimmer pack in question is worth the $999.99 Buy-It-Now price? There's also a "Make Offer," so what might be a fair price? It even has the "classic" TA4 data connectors!

Mr. Duck: Can't say I agree with Yamaha, but thanks for the citation. I'm guessing the writer had a bad experience with the "Chinese handcuff type strain relief" crushing/breaking the inner conductors of a multi-pair cable, which says more about the cable construction, especially the outer jacket and gauge of the conductors, than about the grip itself.

 

[DuckJordan]

Mr. Terry: "'Deluxe strain relief' Kellems grip" for me it is then.
So you don't think the dimmer pack in question is worth the $999.99 Buy-It-Now price? There's also a "Make Offer," so what might be a fair price? It even has the "classic" TA4 data connectors!

Mr. Duck: Can't say I agree with Yamaha, but thanks for the citation. I'm guessing the writer had a bad experience with the "Chinese handcuff type strain relief" crushing/breaking the inner conductors of a multi-pair cable, which says more about the cable construction, especially the outer jacket and gauge of the conductors, than about the grip itself.

Its also good to note that with that kind of strain relief after just a few months of use it can tend to loosen up and not be very effective form of strain relief. I have never seen one of those chinese handcuff type strain reliefs be attached to the cable itself and tends to just pull through even with it there. I know the first thing we do at the CC when we get cables like that is remove that and use heat shrink to do strain relief.

 

[STEVETERRY]

Mr. Terry: "'Deluxe strain relief' Kellems grip" for me it is then.
So you don't think the dimmer pack in question is worth the $999.99 Buy-It-Now price? There's also a "Make Offer," so what might be a fair price? It even has the "classic" TA4 data connectors!

Mr. Duck: Can't say I agree with Yamaha, but thanks for the citation. I'm guessing the writer had a bad experience with the "Chinese handcuff type strain relief" crushing/breaking the inner conductors of a multi-pair cable, which says more about the cable construction, especially the outer jacket and gauge of the conductors, than about the grip itself.

400 bucks sounds right to me. That's$33.33 per dimmed circuit--about the right number for an item of this age and quality.

ST

 

[jstandfast]

Concur w/ Mr Terry about the price. No comment about the data connectors, we try not to think about them too much...........