Soldered Socapex type 19-pin cable and plugs problem


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Hopefully Dave can insert the photos if of any use to what I saw. In any case here is my concern and given I don't sit on any USITT or NEC panels, it migh be a while until my concerns become considered as a possible safety problem. In any case here is the problem to avoid.

Today I was called over to look at a one month old 19-pin Soco cable that was not working properly. The cable had just come off a tour wrapped in red tape, it’s much older male counterpart that was plugged into it followed a few hours later but besides some discoloring of the pins from heat and a slight arcing of a single ground pin, otherwise it was in good shape internally and externally. On this new cable however pins 3&4 at the time had intermittent contact, and 5&6 had nothing and my assistant stopped there in calling me over. Upon observation of the connector and its sockets (female side) there was a bit of scorching to the contacts.

We opened the connector and saw something I had not seen inside of a plug since the “How waterproof is a Soco type plug when under water” test during a very wet show in Central Park a few years back. Water resistant perhaps but not submersible in six inches of mud and water once park grounds and grass - even if wrapped in a plastic bag. In this case the crew people having used the plug that went up in a puff of smoke, said the cable was on a truss in the air in an indoor stadium of which all shows were and had already done quite a few shows on the tour. The connection had also been taped together to prevent it’s taking apart during strike and thus had not been opened since it was initially tested and left the shop for the tour some two or three weeks earlier and many shows before the problem. It was also not un-plugged while hot, it’s load being two Mac 300's and four Mac 600's was also a very light load on a 12ga., fifty foot cable. In other words, besides the probability of the crew setting up the show somewhere in Texas where men are men, in having un-coiled the cable and stretched it along the truss with the two problem plugs already connected, than some internal wire probably about pin four coming loose by being stretched out and the conductor having some pull upon the pin or already having been loose in connection and finally getting hot enough to fail, the local crew also was not at fault.

This cable was used for 208v power to the fixtures. - In other words all pins 1-12 were hot, but because the fixtures themselves much less the cable the one that burned up was plugged into did not show to be the cause, this new cable is the source of the trouble. That the AC Distro unit said cable in melting down did also not trip before the problem or a short both between phases and ground got as bad as it did, this is also of concern because it should have given the damage.

In the bad female connector, up to 2" of wire and 1/4" of gold coated copper or brass pins vaporized on some conductors - primarily the Y and Z phase in pins 5&6 and four out of six grounds pins 14-16 and 18 vaporized both in loosing anywhere from ½" to 2" of wire. Though all three phases did melt down eventually, pins 3&4 were not as melted in only losing about ½” of wire, and still no longer in contact with their pins. This is given a specilized patch/phasing of pins 1&2 being X phase, 3&4 Y phase, 5&6 being Z phase as otherwise safe in a situation where a cable feeding 120v fixtures is plugged into a 208v power source. Two power sources on the same legs of power as otherwise a hot and neutral don’t allow a return path without the neutral or opposing phase thus 120v lamps don’t go super nova. Pin 7 as evidence of the problem below, also had come loose from it’s still somewhat in-tact pin but was not vaporized yet in also going up in smoke as further evidence to the cause.

After thinking about this for a while, taking some pictures for the company that manufactured the cable and mounted it’s wires on the connector and another set to the manufacturer of the plug, than also seeing solder melted into the insulation around the wire and jacket up to 3" away from where the melt down occurred, much less confirming with the crew people the situation, I think I have narrowed down what happened.

Given this cable had a fairly small load on it, it could not have been heated by way of amperage beyond capacity in melting a solder joint. Given it also had been used indoors on a tour during summer for many shows before the occurrence with a taped connection that would not be taken apart, it could not have been a loose connection or spun insert surrounding the pins within the connector in linking up opposing phases. Much less in seeing scorched sockets was it because someone un-plugged a hot connection. Instead this plug a solder type plug where the conductors are soldered to the pins had a bad solder connection of wire to pin and it either by being stretched out and perhaps pulled some in laying it out had pulled the wire from the pin or in being a high resistance connection some how had melted down both wire and pin than caused the problem once what was left of the hot wire went free floating within the connector.

In any case such a problem is why I always recommend crimp type pins where the connection of wire to pin is always mechanical and not based upon if the soldering iron is hot enough or the person doing the connection knows how to solder large gauge wire to a pin. XLR wire is easy to get hot enough and learn, multi-cable wire is a wee bit more difficult to ensure a proper joint.

I now have 35 more cables of the same lot number which potentially can explode some time in the future by way of a bad solder joint to it. Same with XLR cable, a bad solder joint can cause gremlins in the system, only in this case we are talking about three phases of power all shorting at once in addition to all phases shorting to ground - anything including someone touching the lighting equipment or truss providing the path of least resistance sufficient to vaporize copper wire can also be shocked once hot meets ground. Technically this also means - not that I would be able to track down such equipment, but even the wire rope rigging steel in having been exposed to current needs to be thrown out if by chance the building it was attached to provided a better ground than the system’s ground which vaporized.

I do not consider soldered Soco type cable to plugs safe to be using because as obvious in this condition, once the solder melted, it formed a bridge between phases and helped to cause the overall melt down of the connector with not only what ever conductors had the problem but in the end many phases and conductors. Not to mention once it got hot enough there was really nothing holding the wire to the pin in adding to the heat and overall failure of the connector.
It also in other than a ratcheting crimp tool in not being a proper mechanical pressure fit connection to the wire which would not melt down or pull free from the pin than wandered around inside the plug shorting with all kinds of other pins proved the source of the problem. Surprisingly while the card board protection for the body of the plug did not catch on fire, it was only scorched by the heat but did still protect the body of the outside of the plug from proving a path of least resistance. In this case given live wires free floating inside the plug, the insulator protected the plug itself from killing someone had they touched it.

Had this cable been crimped instead of soldered these wires will have never shorted together by way of wires pulling free of pins. Even Pin #7 while it did not short to other pins had sufficient heat applied to it that it pulled out of it’s contact. Say $100.00 for a soldering iron of sufficient power to solder 12ga wire, and $200.00 for a proper crimp tool plus another $250 for a spacing turret head to make it easier to align the pin to the crimp jaws should such a time saving spacer be within budget. This verses the price of replacing a melted down plug, labor in doing so and beyond that what happened at the show when a connector went up on smoke causing union labor and a lot of time to replace it or in a worst case scenario someone died in being a path of lest resistance. Even for a ground, there should be some mechanical means of grounding the wires together beyond solder that when it melts it not only prevents permanent bond wire to pin when the pin otherwise does not have a wire feeding it, but solder tends to follow gravity in bridging opposing pins or phases once melted. Solder for a ground can be used to mechanically strengthen a metal to metal joint due to some amount of movement within the pin and wire which could otherwise loosen the metal to metal contact by such movement but should never substitute for a metal grounding ring in being something which can melt in becoming conductive liquid than provide an even worse problem.

The cable in this case was 12ga/14 conductor and since the new Socopex MonoPc plug of choice stands up to abuse better than other brands of plug, but is having problems in getting their new product out to the market in crimp type pins - much less replacement parts, I made the mistake in accepting solder terminals bonding to the wire even with a problem with that type of connection has as evidenced here been known to me. Given the choice in plugs of other brands with other problems, this seemed a good solution in maximizing the life of the connector in this brand lasting longer in normal conditions against stripping out in a few years as opposed to possibly as crimped connection by brands that have known problems in other ways.

Given a problem in someone giving a bad solder joint no matter if at a factory in someone doing such things for a living or you doing the joint, if it’s a bad connection the plug might very well go up in smoke. Solder type pins while popular and marketed in the industry in a way that allows people to think that anyone can now make such a cable to pin bond without buying expensive tools is false. This as opposed to a crimped connection that besides problems with a short due to water - out of literally hundreds of cables, I have not yet seen one wire come loose from a pin much less only two total melt downs in five years in dealing with a huge amount of multi-pin cable. Should you buy Soco type cable, get crimped wires to pins. The sales people will attempt to offer a solder type pin at a lower price, and given it’s a factory doing the connection you would assume that the pins won’t melt. All it takes is one sleepy employee and you can have a melt down and major expensive problem. Sure you can get a outdated Soco type plug at 50' for $171.00 that won’t last in metal hardness more than a few years and also uses soldered connections, but for a up to $100.00 more per cable you can otherwise specifiy the plug you wish installed on their cable and type of pin used. Parts for replacement cost me $55.60 for a new plug and about two hours labor for my current assistant who needed further experience with such plugs but also required my higher pay scale time in supervision. Believe we done lost money much less money in not having the stock cable available for the show or future shows until repaired. This as opposed to about $200.00 for the cable and a worry on my part that the other 35 cables bought that day with solder joints might also have a wee bit of a problem in wires soldered to cable. Ticking time bomb as it were in what’s going to melt down.

My opinion, avoid soldered cable to pins on Soco type cable - I have always been less than trusting in it, but in this case my fear was realized. All it took was one wire either coming loose from a pin and contacting another pin or resistance of pin to wire being sufficient to melt down than bridge to an opposing phase. In any case completely the fault of a soldered pin connection and could easily have been prevented. If you have such cables and have used them for years, someone probably did their job in making the cable and it’s probably safe in that if they have not failed yet, they probably will not. For new cable on the other hand don’t trust skilled labor at the manufacturer or in your shop to do their job, just get crimped wire to pin given a crimp tool in ratcheting given it’s set to the proper wire size, won’t release until it is properly crimped to the wire and will than never come loose. We are talking about if you make the cables, $450.00 crimp tools if not more expensive yet pneumatic ones. Well worth the investment if someone screws up.

In the end, my mistake for choosing the company that has the cable type and jacket our crew chiefs like most, much less the prime plug they offer I consider just as un-safe in both it’s grounding ring, strain relief too frequently failing, much less it’s keyway stripping out with use as the problem with the old Veam VSC standard for the industry, and it also normally being available in solder type anyway - no doubt a labor thing. Beyond this, in this instance also me at fault for the problem on a high profile show of cable exploding in the truss, by way of accepting the solder connection since the crimp style was not in stock and I was low on time to get such crimped plugs from other sources for them given Socopex (France) is very difficult to get plugs much less parts from. This all as opposed to buying plugs elsewhere and shipping it all out to them as I have done before with other things, and above all my fault for not finding the time to build the cable myself in knowing better than to trust solder pins or other people’s work given the solder pin. Such cables I have made in the past never have problems and I do trust. This very large company making them for me somehow did not have the same quality control. My own being suckered into the new line of Socapex plugs as being superior in this case in the long run as a plug resistant to abuse prevented my general thoughts about crimp verses solder connections in seeing the importance of a plug that would not fail during a show catastrophically verses one if done right would last longer than the other plugs on the market. The new Socapex plug is superior in that it wont’ strip out in it’s keyway as fast, and does not need tools to service, bu in the case of their solder type plugs given an inept person fabricating it to the wire caused much more profit loss than a plug that will not have lasted as long but was in the case of Veam still not what the supplier will have pushed using, but safe to use as in this case still the industry standard given an all aluminum body the best plug on the market.

Point of all of this is not to trust solder pins on your multi-pin cable no matter how good the plug itself might seem. Should you or someone have a bad day while making it, it could fail if not kill someone once it does because once that solder joint melts in connecting wire to pin, it’s going to be as a blob of conductive material connecting opposing pin to pin and phase to phase beyond the damage of any live loose wire does inside of a plug otherwise in just contacting one pin to pin. The more pins in a plug as a whole get hot, the more solder there is in melting and further providing high resistance contacts. Much less in the case of the solder once melted in bridging the gaps to other pins.

This one plug now is going to foster a necessary inspection of all other 35 cables in this lot number much less no doubt an equal amount of cables if there was as similar order to it a few weeks before - this being our busy season in buying lots of stuff at the last minute to cover a shortfall or need. This cable and plug on it being something we paid extra for and I specified as something I wished for us to be using already presents it’s own problems in the necessity of inspecting it verses last year’s cable having problems with it’s Soco type grounding ring possibly becoming a free floating disk of metal within the plug also of concern.
This in addition to a Cyc light re-wiring project, Scoop light re-wiring, Strobe light structure of the fixture project, ongoing S-4 lamp base project, Beam Projector project, as recently added a follow spot ballast project, and above all a AC Distro project that without my efforts seem to be exploding with even more effort and frequency much less cost in shipping out working Distros for replacement across the country overnight. I need a vacation much less an assistant to help beyond the immediate we need X needs to get the show out the door much less to repair normal things such as cable. I’m gonna look at a few more cables of this lot number and if they are also bad I like my boss will about at the end of my ropes in having skilled tech people in this industry either in his case the crew requesting the gear, or in my case the people manufacturing it much less also the crew in making 10' jumpers into Stage to Edison converters in that both the site survey missed such a point and the crew chief did not just add such a simple thing to his list. Yet bitch he does when his at one time 10' cable now gets down to 9' in constantly having to have to be cut and have a new plug installed upon it. Overall, I think It’s vacation time for me having gotten the long working hour needs of the last tour out the door now.

Hope the advice on more than just Soco style plug but specifically crimped plug helps to awaken both the necessity to know what you are doing with it and to get crimped plugs even at a higher initial cost.

I am very happy to say that (virtually) all our power plugs and sockets are screw type. I think I have only a few which require the conductor to be soldered directly to the pin.

I wonder how experienced the factory solderer is? Would not surprise me if it is the new guy!

I have had a few of the moulded IEC connectors straight out of the factory wrapper missing the earth and one in which the active and neutral were crossed over.

As such, I meter all new cables.

BTW - great post Ship - cannot wait to see the pics. Perhaps the manufacturer will let you keep it for your "Wall of Shame"
Thanks ship, once again for the insite. I have never had this problem yet (knock on wood). Wish i lived closer, i'd come give you a hand having a soldering party. I love my heavy duty ratcheting crimpers. They are a life saver, especially when it comes to crimping 8 AWG. I didnt even know they made a crimp soco connector (AH, all the time saved soldering).
I've seen many hundreds of soldered wire connections over the years, and can count on one hand the number of failed joints I've seen.

I've seen only many dozens of crimp connections over the years, but need both hands to count the number of failures I have seen.

The problem - or the solution - is in the hands of the assembler. Either method can be a disaster if the assembler is lazy, inept, improperly trained, or is not given the correct tools for the task at hand.
I agree with Ship, there is no place for solder in a mains plug.

There aree two factors that need to be considered in this what is essentially a risk assessment. The number of failures is one, but we also have to consider what happens when it does fail...

A crimp connection fails, if yous strain relief is properly done, you get arcing and otther nastiness. Because the strain relief worked, thw wire doesn't move...

A solder connection starts arcing and solder melts. This solder can then flow through the connector, shorting stuff out as it goes.

Now there is one thing worse than a soldered connection, and that is where some bright spark decides to tin wires before putting them into a screw terminal etc. DO NOT EVER do this. When things warm up, the solder softens and the connection goes high impedance and nasty things happy...
Bootlaces were invented for a reason people...
Bootlacing becomes more important the bigger the cable in my opinion because the forces applied by the set screws in a power lock connector are not insubstantial and a bootlace helps dissipate these forces across the whole wire. It then doesn't cut the strands and you get better elevctrical contact anyway... We have a crimper at work that will do lugs up to 120mm2...

I work a lot with signal level mutipin and I have had other people's crimp connections fail when I go to insert the pins. It's about skill and practice. The biggest fault I see is when people crimp insulation and then either the connection don't pass juice or more likley the whole wire comes out when you insert the pin. I think this is a timely point to remind people that in the context of mains, if you don't know how to do it properly, then don't even try... You get a mic lead wrong it might be out of phase or not pass audio. Mess up a mains lead and it might shick you or someone else.

Might I also point out that given correct tools, a crimp connection is much faster and easier compared to tinning connector and wire etc... After a couple of hundred crimps your hand muscles even develop such that they don't hurt after doing a batch of multipin...
...Bootlaces were invented for a reason people...
Bootlacing becomes more important the bigger the cable in my opinion because the forces applied by the set screws in a power lock connector are not insubstantial and a bootlace helps dissipate these forces across the whole wire. It then doesn't cut the strands and you get better electrical contact anyway...
By bootlaces, I'm guessing you mean ferrules, or more properly (for shoelaces) aglets. I fully agree with your sentiment, if not with your nomenclature.;)
By bootlaces, I'm guessing you mean ferrules, or more properly (for shoelaces) aglets. I fully agree with your sentiment, if not with your nomenclature.;)

We actually call them boot lace pins and that's what they are listed in the manufacturer's catalogues as. But then again, if we can't agree on things like whether to call our refuse rubbish or trash, then we're going to have an uphill battle on agreeing what to call little bits of metal now aren't we...

I may not have mentioned it earlier, but I've found that boot lacing actually makes assembling screw terminal connectors easier...

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