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welcome and thank you for joining us today I’m Jennifer Matthews and I’ll be your moderator for this master’s of reliability webinar on separable connectors common failures and how to avoid them the content of today’s webinar builds upon our mission to extend craftsmanship mastery to circuit owners and their contractors to improve reliability for those of you new to the Masters to reliability webinar series links to recordings of past webinars may be found online at the link provided on the screen while you’re there please also be sure to sign up for my ex Polly’s P 1816 implementation webinar on November 2nd joining us today is our expert guest speakers Glenn Latia of Richards manufacturing company he began his 40-year career of power engineering with the oka night company as a research engineer in the high voltage laboratory at Alaska mold he was promoted to director of engineering where he had the design and development efforts for joints and separable connectors he later joined Richards manufacturing company as the manager of the medium-voltage product line Glenn has authored 20 US patents and serves as chairman at the committee responsible for revisions to the I Triple E 404 and with that I’d like to turn the presentation over to Glenn Thank You Jennifer before we begin I’d like to extend a thank you to Glenn Bertini for having the vision to recognize the value of something of this webinar series to our industry and also thank jennifer for all your untier to help in putting today’s session together here is the agenda that we’re going to be going through today we’re going to start with a definition of separable connectors and look at the specific types that are available today we’re going to look at the industry specifications that govern separable connectors and then we’re going to get into the failure mechanisms and what I’ve done here is I’ve broken these into cellular mechanisms that are related to the current tyring portions of connectors and then those that are related only to the voltage of the dielectric portion now you have to remember that most current related mechanisms may start as a heating problem but the only way you find them they only manifest themselves to to engineer is when they become a dielectric failure and they trip the breaker out and then we’re going to wrap up and at that point we’re going to take questions after the wrap up now jennifer has told me that you can put your questions in as we go along I urge you to do that and she will keep track of them this way none of them are forgotten lift that will get started here hopefully when you’re done today you will be able to understand the three classes of separable connectors that are currently in the I Triple E 386 standard that’s the 2006 version of I Triple E 386 now there is a fourth class that’s why I mentioned four classes up here in the next revision of I Triple E 3d6 we expect to have another class of separable connector which we’re going to go through today we’re going to go through the standards that govern not only the geometry but also the ratings and the qualification requirements for separable conductors and then we’re going to go through current and voltage related failure mechanisms so you can understand the differences between them and then recognize the root causes of either one of them and when we have all that together this will give you a much better understanding of how we can improve the reliability of the connectors of separable connectors and ultimately the system so let’s start with the definition of a separable connector this is the definition as you see it I Triple E 3d6 today there’s only two areas that I want to key in on here and those are the two areas that differentiate a separable connector from other connectors like a live front termination and the first section is the fact that a separable connector is fully insulated and fully shielded obviously a termination is not shielded the second area in this definition that differentiates these connectors is the fact that the connection can be easily readily established with broken what we mean by that is if you have a long break elbow you’re on the end of a hot stick you can engage the elbow to the insert and complete the connection so you’re establishing the electrical connection or you can remove the elbow and break the connection so the separable connector types the first type that I’m mentioning here is the 200 amp load blank and that’s because most people are most familiar with this but the reality is the 200 amp dead brake system was really the first floor one of all separable connectors and the differences between the two of

these one you can make and break under load on the left side the load break one and the dead break one a circuit has to be completely de-energized since these two systems are very very similar I’m going to treat them going forward as one group the last group that’s in the courage standard 2006 version of I Triple E 3 d6 is the 600 dead brake system and this is either people calling T bodies or hammer heads or 600 ml bugs that’s what 386 looks like today hopefully in a few years by the way Tim wall is the chairman of the committee that that is looking at the revisions next revisions to I Triple E 486 and so he will be responsible for putting some of the things that were going to be talking about into the next revision the disconnectable eyes lies in h joints here now the first question that may come to mind you see the word joint people call them joints or splices the first question is where why are these going to be put under I Triple E 386 both Tim Walz group the separable connector group and my group which was the standard for joints both groups decided that because of some of the similarities they were best suited to go into physics in particular there is a lug that gets bolted in here it happens to be exactly the same lug that you’ll find in the 600 app the brake system also if you look at the back end of the 600 M dead brake elbow it’s exactly the same as the back end of the disconnectable splices and they both accept the same cable adapter now we’re going to be talking about cable adapters going forward and currently the standard does not have any geometry related to that but the next revision of 3d6 is actually going to call out the geometry of the cable adapter so those are two similarities and then finally this t body the syndrome dead break elbow there are many accessories of sodium associated with all of these connectors but there’s one accessory in particular what we call a connecting point where you can stack two that break elbows together and that’s a joint or splice configuration so there is a precedence to say why this joint should be in 386 now let’s look at these in some in a bit more detail the 200 amp load break or dead break system consists of an elbow housing and insert and a well bushing well the 600 am dead break or t by t bodies consist of again in elbow housing and here you can see the cable adapter which I will call out in this particular screen we have the apparatus bushing and finally an epoxy insulating plug and cap to close the hole connection together by the way we call it an elbow even though the shape is far from an elbow shape but since the 200-amp won’t break and dead break elbows were the first systems we that name sort of hung around elbow the disconnectable joints again these are not innings in the current standard but they almost definitely going to be in the next revision they consist of a splice body or a yoke and a sleeve or receptacle now let’s look at the industry specifications we’ve been talking about I Triple E 3 D 6 the actual title of this standard is the separable is the standard for separable insulated connector systems for power distribution systems above 600 volts the first change that may occur in 386 is in the title and that’s only because the word above 600 volts is it really definitive the standard only goes up to 35 kV even though that’s usually the maximum distribution voltage this may be changed that yet to be seen within I Triple E 386 there is a few standards one of them is I Triple E 592 and the title of that standard is the expo if it is the standard for exposed semiconducting shields on high-voltage cable joints and separable connectors now as we mentioned in the first law one of the first slides early on that the outside surface of these connectors are fully shielded they are fully shielded but they are shielded

with a semiconducting rubber now the value of I Tripoli 592 is it specifies what that semiconducting shield must do obviously when an elbow is sitting out in the field energized and somewhat enters a manhole where one of these connectors is and they accidentally touch the connector we certainly don’t want anybody getting hurt so one of the requirements of 592 specifies what the insulation existence has to be from end to end of that connector the other portion of I should be 592 many people know it as the nail test this is the area where imagine a separable connector in the field and it somehow the dielectric punctures excels we want to make sure that when it pushers that the semiconducting shield is capable of tearing the fault current to remove the breaker at a service to drop the load from Hartigan and in reality 592 requires have to happen two consecutive times they’re not going to get into that why at this point okay another standard it within I Triple E 36 that numbers these connectors is ANSI C 119 points for I think everyone recognizes this standard again this standard has just undergone a major revision up until the last revision this standard was for connectors that we use between aluminum cables a loop to illumine or an aluminum to a copper cable this current revision now has performance criteria for a conductor that’s used on a copper the copper system so just a quick poll something for people to think about while we’re going through this is most medium voltage connectors share common failure modes yes or no and this is all the different connectors the 200 amp load break the 200 am dead break and the disconnectable splices and the 680 bodies do they all share common failure modes so now let’s start here before move on when people had a chance to answer okay three more seconds alright I’m closing with oh now and there’s a quick share of a float everybody we’re tied with okay all right I’m gonna okay I’m not sure I see the results here but let’s go on and we can all think about it for those who who haven’t answered we’re going to look at again I’ve broken the failure mechanisms into two groups the first group or you look at just those mechanisms that start as a current related mechanism so again let’s look at the 200 amp load break and dead break connectors we’ve identified the elbow housing just so that you can get your idea of where this picture is we have the housing we have the insert we have the bushing well since we’re talking about current related phenomena the more important families are what’s on the inside on the inside we have a probe the elbow code and that when we’re talking about load break connectors this always has a tip a plastic white tip that tip is an arc quenching tip what the purpose of that is okay someone might be new to this whole line of connectors as you start to remove this elbow off an energized circuit again we’re talking strictly the load break elbows as you start to remove it you’re going to develop once once the lapel probe breaks the connection with the insert we’re going to develop an arc there that arc at that point this odd quenching tip is going to be right in the area where the arc is that arc is going to play on the surface of the art pointy tip it’s going to ablate the surface or melt it when it ablates it’s giving off a gas which tends to quench the arc by increasing the dielectric strength of the air in there so that by reducing the arcing time so the other part of the connector system that we’re going to be looking at is the connector itself so what do we have to worry about bill tell it in his first presentation in the first presentation in this web series talked about cable preparation in depth there’s a few things I think that we should go through them just it’s worth saying over and over again again we’re talking about cable preparation only in the area right now we’re limiting it to exposing the

strands of the conductor so you’re cutting through the insulation and removing that insulation off the end the first thing we have to make sure is we don’t cut any strands it’s obvious that if we cut a strand let’s take a number two cable it’s a number two it only has seven strands if we were to cut one of those strands and we’re carrying full current we’re carrying two hundred amps now we only have six strands left to carry that 200 amps and also six strands left to carry 3500 amps for three seconds or 10,000 amps for ten cycles ones are all currents that have to be carried by those remains strands now it’s not hard to imagine that with less strands carrying current we’re going to get a localized hotspot here what happens is that heat that is generated in this area is going to start degrading the insulation the dielectric of the housing and eventually we are going to end up with a voltage related failure we’re going to end up with a puncture right out the side of the housing somewhere in this area but again it began as a current related phenomenon now another problem is nicking the conductor they might say well that’s not so bad if we lick it it’s still going to carry most of the current that is true except for one thing if you Nick put a small Nick in an aluminum conductor cable and there’s a mechanical force and there will be as the cable heats up expands and contracts if there’s any through folks there’s going to be movement in that area eventually where that Nick is the Strand will break and we’re going to end up with exactly what we had here a cut strand the same issue we’re going to end up with a dielectric puncture in this area now another area the next two items are really tied together the number of crimps and the proper Dyson tools by far this is the most critical area of the current carrying portions of the connector the dies are fairly straightforward the dies in the tools these are the ones that this that the splicer has on his truck what he doesn’t have is the number of crimps this is something that every manufacturer supplies with the connector now let’s go back a few years when cables cables were strictly stranded Kate stranded it was no strand filling if you put two crimps on a connector and we were carrying instead of 200 amps we were only carrying 30 amps audience which is a normal current for most of these connectors from most of their life to prints probably would have carried the current it may even be carried the 200 amps for a while the problem is today the growing strand fill cable usage is growing a lot two crimps will not work if the recommendations by the manufacturer say that if you’re using a BG nose die you should put five prints on and you only put three crimps on eventually that connection is going to overheat and we’re going to have a dielectric puncture so that’s probably the most critical area that we’re going to talk about one other area we’ve got the cable prepared now and we’re going to put it into the connector it’s very important to seat the conductor all the way to the bottom if you put the first crimp on right at the crepe line which is up here somewhere and the conductor is short it’s not underneath the die you might as well assume that you didn’t put that particularly crimp on so you’re back to the same issue as having too few crimps now another area is the probe to the connector where that connection is made we have to make sure we have the proper torque the good news is that every elbow goes out every manufacturer supplies a wrench a furrow a wrench with every elbow it’s a probe wrench there’s usually a hole right in the probe about over here the wrench goes into the hole all the splicer has to do is tighten this connection up thread this in and tighten it until that wrench bends if the wrench bends he knows he has the proper torque and also the 200m dead brake connectors also have a strongly wrench similar to that now there are tools on the market that have built in torque limiters on them that’s also another way to do it another area of the current-carrying portion is is this insert and well stud frayed

connection this well has a three a sixteen coppers right here that copper stud has an ultimate braking torque of about twenty foot pounds and in fact I typically 3d6 has a performance criteria that a manufacturer has to take for parts and has to be able to show that it will hold 17 foot-pounds what happens is when an installer is putting the insert into the well he greases everything up properly he’s sweating it in it is not difficult when you’re gripping the outside surface of this of the insert to put to exceed twenty foot pounds and break that shtetl stud off that’s certainly bad news initially but the news gets worse because now you’ve got a splice or who knows they put a certain he was twisting and he broke the study we can be sure that every subsequent part that he puts together he is going to remember that he broke the stud and that he has to be careful now instead of the accepted 12 to 15 foot-pounds of torque who may only have 5 to 8 foot pedals so that is a problem area okay for the 600 M dead brake connectors we have identified the the cable adapter I mentioned to you the elbow housing and the insulating plug in cap again we’re looking at current related phenomena so let’s see what’s on the inside here all right I forgot we also looked at the bushing so we have that part there so on the inside we have a connector and we have a study areas after that we have to be concerned about cable preparation again exactly the same issues that we looked at on the 200 a ploy obviously a NIC on a sixty one strand conductor isn’t as critical but we want to make sure we don’t do that another area that’s sort of unique to the 600 dead break system is this area the top of this lung usually has a through-hole up here that through-hole accepts this study what happens often is a splicers prepares the cable push the cable adapter on puts his connector on pushes the elbow housing on lines up the hole now he greases the 600 amp mulching and now he starts to move the elbow housing over to put on to the bushing and it’s just a little bit short the cables just a little bit short so he lifts up on the elbow figuring that he’s lifting everything up unfortunately what happens is the elbow slides left the cable adapter and the hole only has to slide down 5/8 of an inch and he puts the insulating plug through with the stud and he misses the hole what happens is he ends up pinching the top of the connector right here he torques it everything seems good and everything is good for a while it will carry current but what happens as soon as he starts getting any mechanical movement again some thermal cycling through faults anything else it will work its way out and eventually fail the front of the threaded connection that uses the stud the first area that is a primary concern is the stud 386 right now calls out to different lengths of stud one stud length the shorter one is for the 15 and 25 kV class elbows and there is a slightly longer stud for the 35 kg class connectors now if you happen to have if you happen if your utility happens you used both 35 kg class and 15 kV class connectors and the studs are loose somehow or other we often see failures occur because a 35 kV stud the longer one gets to the 25 kV application of 15 K the application it’s a little bit longer it bottoms out in the hall the splicer torques everything together he gets the 60 foot pounds II think she’s tight but in reality he doesn’t have contact between the phases there so that’s the first issue also there are several specialty stubs in some specialty connectors out in the field these studs are not even the same length on each sent in on each side if they’re used in a non special application and they’re put in the in the wrong direction they will bottom out on one

side of the hole and again the torquing will not allow the two phases to come together absolutely paramount at the faces of this lug and the bushing make the second area of concern is the torque and everybody knows 50 to 60 foot-pounds the reality of this connection is if you were to put toward this to get only 10 foot pounds it will actually carry 600 amps no problem it will carry 600 amps forever it may also carry 25 ka was not an issue that’s the high shoe fault rating for this connector a problem with it if this connection is tightened to 10 foot pounds and we have a through fault let’s say we have a 25 ka through fault that’s true fault is going to move the elbow it’s actually going to twist it about the stud if that elbow twists in a counterclockwise direction the way the stud grips the inside it will actually loosen up and then when the elbow goes back in the clockwise direction unfortunately it doesn’t retighten so you start with 10 foot-pounds that after the first movement of that connection you only have you’re down to 0 no longer will tell you 600 amps and another interesting fact about this type of connection if the elbow happened to move in the clockwise direction that’s in the direction of tightening the torque so if you start with ten foot pounds you would think oh well I’m going to get tighter what happens is when the elbow it doesn’t get tighter first of all and then when the elbow goes back to the neutral position it moves in a counterclockwise direction that will loosen up the stalk also so an area of concern if the requirement is fifty to sixty foot pounds make sure you’ve got fifty to sixty foot pounds looking at the six internal disconnect splices we’ve identified the the yoke and the sleeves or the receptacle now looking on the inside we have the connector and again as I mentioned this is exactly the same connector that we just discussed exactly the same dimensions everything about it is the same we also have the bus yoke or the conductor of the bus and finally the fastener those are the three areas that we’ll be looking at here cable preparation there’s no sense even going through that again a fastener itself the proper torque essentially we have the proper torque here for exactly the same reason if you tighten up the five foot pounds and there’s any kind of mechanical movement that connection is going to loosen up now in the industry there are some some from specialty bolts that take this completely out of the equation there’s a sheer bolt head on top of this other bolt where when you torque it you shear the head off you know you’ve got the proper torque and if you don’t have the proper torque if you don’t share the head off you can’t get the sleeve on so it’s a fail-safe system that is available in the market now let’s look at some some specific failures relating to torque or dogs like to current to the current portions of the system what you’re looking at here is a t body 600 T body they’ve got a lug you’ve got the insulating plug and you can see the severe melting I’ll do at the end of the lug in this area here now when you first look at this I’m sure the first thing everybody keyed on was the fact that we are looking at one third of this lug and we don’t see any crimps which means the first crimp is way down even if they even if they stunted down here and all the crimps were put on right next to each other there’s no way that they would be able to get the proper number on but again when we looked at this we would have expected a failure out the side of the housing down here so where the the hole was actually right up here and it’s in the half of the elbow that you can’t see the failure is looking right at your eyes now that’s where the hole was and the way you finally determine that there is insufficient torque was we look at this surface on the backside it looks a little distorted distorted here but it was actually straight and we saw black marks around the entire surface there should have been a circle one and a quarter inches in diameter which represented the bust bar in the bushing you’re going to see this a little bit later much player in in a different picture and a different phenomena another current related phenomenon and

again insufficient crimps like we’ve talked about this is a copper conductor cable the lug here is copper this connector in the next revision of I Triple E 386 is going to be considered a 900 amp connection with three crimps there is no way that this connector could have carried nine hundred amps now we know it was tore together properly remember I mentioned that there should be a mark you can just see the surface of the one here that outline that outline is exactly one and a quarter inches in diameter and that’s where the bushing contact or the insulating plug contact moved around the surface and smooth it off we saw this impression on both sides so we know the torque was proper over here so the heating was occurring over here and right where you would expect that this is the hottest portion of the connector between the end of the insulation in cable laughter and the end of the one that’s the hottest part they damaged the insulation in that area and we had a failure a puncture the dielectric right in that area now let’s move on to voltage related phenomena when we talk voltage the first thing we everyone thinks about is electrical stress analysis and this is a typical stress plot what we have here is we have the cable conductor by the way these are a season these the ones I’m going to be showing you’re axi-symmetric the line at the bottom of the white circle is the very center of the conductor so what you’re looking at here is 1/2 the diameter of the cable conductor then we have the cable insulation here we have the accessory jacket and this particular accessory is either a 600 ft body or a disconnectable splice and we know that because of while you’ll see in a moment the cable adaptor this is the conductive insert of the t body and this is the insulation here this section here is the cable adapter insulation and the cable adaptor stress code so we have this stress plot what do we do with it here’s how a manufacturer uses a stress plot stress analysis before we run the stress plot it’s essential that we determine or have a good idea of what stress our materials are able to withstand on a continuous basis this is the bulk insulation all this area the cable adapter this is all bulk insulation here what stress are we going to allow here now let’s say for the sake of argument that this connector we want to have no more than 120 volts per mil by the way I think better’n volts per mil difficult for me to think in kV per millimeter so I will only be talking about spur mill we’re saying that we have a requirement that anywhere in this bulk insulation we cannot exceed one 20 volts per mill that’s not the end of it we have two interfaces every separable connector has at least one interface the interface between the elbow housing and the underlying material in this case it’s a cable adapter if it happen to be a mode brake elbow this would be cable insulation so we have to identify what stress we want to allow here and in a t body we have two interfaces we also have this interface between the cable adapter insulation and the cable insulation so let’s say for the sake of argument that we allow for a maximum of 40 volts bundle anywhere along any of these interfaces so we run the stress plot these lines that you’re looking at here there have to be 30 of them each one of these represents a point of a constant voltage so if you follow this around the voltage in any one of these points is exactly the same and since there’s 30 of them let’s say for the sake of argument that we’re going to put that this is a 25 kV elbow a 25 KBT body only has a single-phase rating which means most it can have trust it is 15 point 2 kV line to ground so on our cable conductor limited put 15 kV and on a jacket and shields running out of zero so if we have 15 point 2 kV we know that the voltage difference the delta from one line to the next is we have 30 lines here 15 kV or 15 point 2 KB we have about 500 volts from line to line so if

we know the distance between the lines it’s simply 500 volts divided by that distance for the most point you have to make sure you resolve that vector into its two components the vectors are normally giving given 10 perpendicular to the stress line so let’s look at another stress plot this is an improper cable preparation on the right side we have proper installation this is exactly the stress part we just looked at and again since it’s both plots are actually symmetric symmetric it almost looks like a complete part here but the left side is where we’re going to look at the difference so let’s look at the elements that we just identify again we have the cable conductor and that’s the cable conductor on both sides for the proper installation or the improper installation we have the cable insulation we have the accessory jacket the conductive insert the the insulation system of the accessory the cable adapter insulation and the cable adapter stress code so you look at that plot and everything you look doesn’t look too bad but let’s see in one particular area on the right side I’m calling this a proper installation on the left side we have a problem or what is the problem on the right side the cable adaptor this is a cable adapter it ends way up here right flush with the cable insulation both of these dielectrics are terminated well inside the conductive insert on the improper installation you can see the cable insulation and the end of the cable adapter are both short of the conductive insert so you say well so what’s the problem if you look at the stress lines the equipotential lines there they don’t look a lot different yeah they’re bending a little bit more up here so what is the problem let’s look at a little deeper this this area right in here we said we have 40 volts per mil along the interface perpendicular stress maybe 50 volts them though now 50 volts per mil in the PD M is well within the operating voltage of that material certainly within the operating voltage of cable insulation on this side you can see that stress line is bending a little bit more when you do the analysis it may end up that we’ve increased the stress instead of 50 volts but no now we’ve got 55 volts per mil again you might be saying so what’s the big deal the problem here is this cavity which should have cable adapter insulation and cable insulation has air instead what’s the dielectric strength of air for a cavity this size we usually use a number like 45 volts or maybe 50 balls per mil so what’s happening here we said we have 55 volts from illness area now you can see the problem the air can’t hold off that dielectric strength it’s going to start buzzing I shall discharge that partial discharge is going to start unloading the insulation in this area it’s going to erode it continuously until eventually you have a puncture out the side here now let’s look at some specifics with the connectivism again we’re one thing in the dead break and the load by connectors together here’s the 200 app you’ve identified the well so you see them again we’ve identified the housing insert and the well inside we’ve identified the connector the probe now let’s look at areas that we have to be concerned about cable preparation before we talked about cable preparation we were keen on cable preparation as it related to the area of the inductor now we’re looking at cable preparation on the installation service the first most important thing not most important but an important thing is that the cutback is correct you can see here down here in the lower portion of this slide this is the insulation shield the SEMICON the SEMICON is short it should be inside the housing here we all know that if you see insulation here there’s a potential problem so cutbacks are critical now let’s say we’ve got the proper cutbacks the next issue is we have to look at the surface and make sure we don’t have any knife

cuts or gouges let’s say we do have a knife cut what do you tell your splicers certainly if it’s a deep knife cut or a deep gouge they have to return 8 the cable hopefully they’ve got enough free length of cable to return 8 if they don’t what they usually will do is try to sand out the knife cut with this sandpaper and that’s ok if they do a smooth job and they don’t leave a flat on the end of the insulation now we’ve got a nice smooth surface everything looks good the next thing we have to do is make sure we have no contamination the contamination on the insulation surface usually comes as a result of residual pieces of SEMICON microscopic they’re very small actual carbon particles that are embedded on the surface of the insulation how do we remove those some utilities allow their spices to go in there with again fine fine sandpaper and remove the contamination that way the better way to do it is to use a solvent soaked or rag which solvent it’s important when we do this that we wipe from the insult from the out from wipe toward the cable always wipe in this direction why do we do that if you wipe with a solvent in this direction from the cable shield down the insulation we’re going to drag part carbon particles from the insulation shield here and we’re going to drag it down the surface of the insulation and contaminate things even worse so there’s now let’s assume we’ve got no contamination everything is clean ready to go the next thing is we have to make sure that we grease things properly now we’re going to talk about greasing the housing also but you’re going to see in a minute that it’s difficult to do that so it’s very important that we grease the cable now greasing does a lot of things certainly makes it easier to try the housing on but Greece also fills in microscopic defects or areas where air can get trapped in particular that Greece is going to build up on the SIRT right in this area where the SEMICON terminates and it’s going to get as you’re sliding the housing on it’s going to push the air out of that area so it makes a much better connection so you want to make sure that that cable is thoroughly and properly greased let’s look at the housing the first problem with the housing we have to make sure it’s properly sized well that sounds easy at the first blush the dimensions are right on the housing using engraved near the bottom somewhere and it tells you what the minimum you’re really usually you’re only concerned about the minimum number on that elbow housing the reason being at the top the top number if you try to achieve that it just it’s too difficult to put the part together and your spacers are gonna complain about it so we’re only concerned about the minimum number what does that number mean it tells you the minimum diameter of this insulation across here that this housing will work properly on so that sounds pretty straightforward you go to the cable manufacturer and you say I’ve got the number to 100% insulation what’s my diameter what’s the diameter of my insulation you get a number the problem is that’s not the minimum number that that can be both ATI see specifications and I see a specifications allow that nominal number in cable installation damage to Barry you have to know what is the minimum that that can be are you done at that point no unfortunately going back to cable preparation if there was a knife cut on the insulation and the splicer funded the knife cut out did he reduce the diameter of the insulation if you did you have to take that into account when we when we are cutting the insulation shield back there are tools on the market that make this much easier some of those tools actually remove a portion of the installation not a lot but it does remove some insulation what does that go it reduces the diameter of this cable even more so the size that’s on here that minimum size is the diameter of this cable just before you’re ready to slide the housing on taking all that into account so now we’ve got the proper housing we got the proper cable all ready to go we have to make sure that the housing is greased again the hole is very small it’s not as critical in this area down here if you could most splicers do put some grease up in there but you can’t

get up in there we do lie on the cable being properly greased over here from the most part when we slide the housing on we want to make sure it’s positioned properly by proper we want to make sure that the lug is fully up to the top here when that’s fully up to the top it allows the connection to be made to the prom’ now if the housing is not properly positioned you’re not going to be able to get the lug in the probe in but you want to also make sure that those probes that the threads are aligned straight out so we don’t do any cross trade now the more critical area for greasing is in these two interfaces and by far the worst area is this the operating interface but for the minute let’s just look at the two of these together we want to make sure that we use the proper grease now these these materials that are used to make almost all these conceptional connectors is EPDM it’s an oil-based lover if if we happen to use say Vaseline to lubricate this surface there is no doubt that it would lubricate it you’d be able to put the elbow together and it would work the problem with Vaseline because it’s oil-based it will absorb into the rubber here first thing it’s going to do it’s going to swell the rubber if there’s not a lot on there it may not swell it too much but what happens is if you come back in three months and try to remove this elbow you’re not gonna be able to remove it so grease type the grease that’s recommended is a silicone based grease the amount of grease that we use now let me go back to grease type one other issue with grease and if I hear this very often I’ve got two greases out here now I’ve got one that’s nice and thin it goes on so smooth I can wipe it so easily on here very easy to make to thoroughly grease this interface and you know what it works fine it works great except if you’re going to remove this elbow in three months you will not be able to get it off what happens with the grease when it’s put on in here is the pressure of the interface that’s built into it pushes on the silicone grease the silicone grease migrates out this way it migrates out this way there was a UConn study done years ago where they actually found silicone grease I believe it was fifteen inches down the conductor of the table that’s how far it migrates silicone grease does not migrate into the insulation it’s a misconception people think of the interface drying out that because the grease got absorbed in it does not absorb in got to use the proper grease the heavier grease stays on stays in place the amount of grease we’ve got the right grease can be over grease it yes this interface if you put too much grease on here but there’s only a very small reservoir down here at the bottom if you put too much on you’re not going to be able to get this insert on proper if you put too much and it takes a lot of extra grease but if you put too much on here you’re going to get it down then this error you’re not going to get the elbows seated properly the bigger problem is using too little grease and that comes down to whether it’s uniformly distributed uniformly applied and again this interface the operating interface the interface that give it a rely on to be able to be operable for the next 40 years you want to be able to remove it and put it back a lot if let’s take the extremes let’s assume that your splicer puts absolutely no grease on he pushes the elbow on he’s a big burly guy he can get it on and he will certainly won’t ever get it off again that’s the first problem but the second problem is as he puts it on this rubber against rubber starts to produce microscopic ripples just like pushing on rubberized running across the floor it starts to buffer you can’t see it but embedded in that that buckled area is my neutral mount of air we’ve already talked about error it has a lower dielectric strength than the rubber you can’t have that just because you apply the grease to ninety percent

of the surface if you don’t apply it to 100% all around you’ve done the bottom where you can’t see it you’re not doing a good job of uniformly applying the grease after you’ve got everything all made it up the final thing that you have to make sure is that all components have to be grounded there are eyelets in the elbow there are eyelets in the insert six hundred amp connectors all have eyelets we’re going to go through those make sure they get tied to ground so in the 600 ed great connectors we’ve identified the housing the bushing and the epoxy plug and the cable adapter cable preparation there’s no sense in going through that again exactly the same thing as we just talked about a cable adapter we’ve talked about this also cable adapters have a sizing just like the elbows you’ve got to make sure it’s sized properly at least properly positioned properly once you’ve got the cable adapter in place the housing is the next thing the good news there’s only one housing 1525 KB housing sits on a 15 25 kV cable adapter 35 KD cat housing only six on a 35 kV cable adapter so that’s an easy one but again half the nature is properly greased the epoxy plug and the bushing two more interfaces we want to make sure that the properly greased and finally everything is done we want to make sure that at least a ground is put in in at least one of the grounding eyes some elbows have grounding eyes up here in the corner some have them down here by the cable adapter some have grounding eyes in both locations one of these has been the ground wire to ground it disconnectable splices cable preparation will need to go through that again the cable adapter exactly the same as before the bus greasing it properly the receptacle most surprises there and finally we have to make sure we’ve got grounds in each of the components in this particular configuration this is a wide configuration so there’s three sleeves we should have a ground on each one of the sleeves and also on the yoke so what does an electrical issue look like well here’s a piece of cable there’s the cable installation you can easily see here’s the cable one and this came out of a t body you can see the knife cuts all along the surface here and those ix cuts caused what we call an electrical creep down through the knife cuts and the fault current came over here and you’re loading the surface contamination here we have a cable adapter and this is the end of the elbow housing you can see a cutaway and you can see your lotion in this area here now this is the way the part came back from us came back to us from the field I urge you when you’re cutting these parts in the field you can see this nice mark that knife mark in the surface of the cable adapter was obviously made when the housing was cut off but sometimes that the person who looks at this last may not have the housing and people say well what caused the failure when you start looking at things like this and you start to wonder whether that’s caused the problem the other thing is normally you would make your cuts away from the area that was eroded so one more this is a tbody if you can see this is the cable entrance down here there’s the area where the bushing would going and you see all this erosion here now this part did not fail in the field it was removed because a splicer went into a manhole heard this elbow buzzing and said there’s a problem he notified his supervisor eventually took the circuit out of commission put the breaker out we moved the elbow sent it back for analysis what we did back here at Richards we cleaned it all up put it back on our production test everything past production tests no problem and then looking into it there are four grounding eyes on this elbow and not one of them was pierced so we knew absolutely although we were pretty sure before that that there was no ground so what happens as the sine-wave altijd builds up you build up a charge on the outside here and it’s going to discharge to the closest ground in this case it

was the faceplate of the network transformer it started arcing to it this I just threw this slide in its not not an electrical problem it’s not a current related problem it’s a mechanical problem I mean it certainly could have ended up in a voltage related problem but this is a spanner wrench misuse of the spanner wrench epoxy parts on the 600 amp connector line has they have holes usually three holes around the circumference and a ret special wrench a spanner wrench goes into the hole you put a torque wrench on the spanner wrench is very awkward to do that’s the way it has to be done and then you tighten it what happens is this the first time someone uses a standard range invariably they put it in in the wrong direction and then you try to torque or what happens it just rips out a section of epoxy the other problem that happens is by the time you put a spanner wrench into the hole and you put the torque wrench on it and you’re all wrinkled and the torque wrench is awkward because you might be hitting something and the spanner line slips out of a hole a little bit and then you put the torque on you crack the epoxy so let’s have our wrap-up I guess we went through our polling over there let’s see how we did the two points hopefully that I’ve hit on is that medium voltage accessories whether the 200 amp load break dead break key bodies separable joints they all have many of them have common failure modes and those failure modes have common causes I hope everybody got that right the predominant failure causes such as too few crimps are easily discoverable they’re understood once we define them and we understand them if we pass that knowledge along to the Installer they can certainly improve the reliability of the accessories and ultimately the reliability of the system so thank you very much for your attention and I hope I hope you got the answer to the question over there and I guess Jennifer I turn this over to you actually I’m gonna let Glenn Brittini ask a few questions okay hi Glenn have some great questions from Nicky and Steve and Gail and Tim and Carl Sheila oh let’s try it but let’s let’s get to a couple of them and then we’ll answer those that we don’t get to by email or something later on okay first question Dale is go ahead line I was just going to say they should email the questions to you you know we’ve got the question on my screen in front of me though okay we’ll take it in there okay um yeah Gail asked these various stud first of all they standardized between manufactures the stud on the 600 amp T bodies are are determined by standard massively 386 there are two of them that are standardized and every manufacturer has to meet the dimensions again the issue was if you have 15 and 35 or 25 and 35 kV class systems in your your particular utility and somehow those studs get mixed up there’s a problem there is also the stud that’s unique to one particular connector system and that is not called up by standard so that’s one that currently falls through the cracks so in charge and error there’s somewhat interchangeable but not universally interchangeable the ones that are called out in 386 are universally interchangeable and by the way something I did not mention the next revision of I took away 386 is going to change the dimensions for the 15 and 25 kV interface so that if by chance someone uses the 35 KB stud if they do get mixed up that it will not bottom out so that’s going to happen in the next revision of I Triple E 36 the old version of that interface effects very very few I believe only one utility anymore so it won’t be an issue okay for those that need to drop off because we’re past our time you know feel free to do so we’re going to stay on for

maybe five more minutes for two or three more questions and before we call it go a sheriff here the next question from Charles is associated with the grease that’s applied on to that interface of the separable connector I think everybody that’s been in the field and operated old elbows has seen this sort of white paste that’s left anything like the grease that was applied 20 or 30 years early earlier so first of all where is that grease going why does it change and if it is leaving do do we need to remove those interfaces periodically clean them and reinstall grease okay um years ago and I’m going back over 25 years now the original greases that we used back then are different than the ones that are used today back then the revision of I Triple E 386 did not have a performance criteria for the grease that’s the first issue once it was just once this whole problem with what we call sticking interfaces came about tremendous amount of work was done and what we found was that those old greases just didn’t work when you put when you mated the interface it does migrate out as I mentioned there was a University of Connecticut study done several years ago it’s probably easy to get a copy of that study but the pressure actually forces the grease out now thin greases that I mentioned when someone uses a very thin grease it migrates out very easily a thicker grease is the ones that are supplied today actually meet the criteria teria that is now in I Tripoli 386 it’s a pre severe criteria what we found is most in most cases the surface is just not the entire surface is not coated with the grease the white film that you’re seeing there what that is is a liquid portion of the grease is migrating out and what’s left is what we call the filler the silica and that’s what the light is that’s left behind and yeah that is very difficult to separate those interfaces you should still be able to get them off one important thing you should do is every time the load break elbows or any of the any of these connectors are separated they should always be regressed now I only caution you on long break connector that’s the most critical one because how do you grease a live elbow the way to do that is if if an FAA splicer is removing an elbow off a live bushing he has to put that elbow somewhere he can’t just leave it floating in air he is either going to put it on to a feed through a junction stand off a grounding plug the best way to do this is grease the mating part well before you put it on to the parking stand this way when you put the elbow on it will now recoat the interface of the elbow okay and it’s sort of a related question what’s the anticipated life of a modern necessarily in decades and do you expect the Greece to remain there for that entire time the the original connectors that were developed I showed the 200 and dead brake connector that was actually developed in 1962 that was the first connector the load brake line and the dead brake line and even that splice line came very very quickly after that late sixties early seventies all of those products that were rigidly developed with all manufactured with them with a sulfur-based curing system unfortunately that particular curing system had a had a life expectancy and it was the higher the voltage the shorter the waistband and it related to the way the molecule the actual polymer is bonded in the lake by certainly by the late 90s 1990s all separable connector manufacturers manufactured their connectors with a peroxide based insulation system and in comparison studies it was these were these were accelerated tests and the the peroxide based materials just didn’t fail the sulfur based materials would fail within weeks two months and the peroxide based materials went years and didn’t fail now if you look at the life expectancy of a sulfur cured material we

do have some very specific data that shows a sulfur-based 600 amp elbow has a life expectancy of 15 to 20 years you know in a dry environment put it in a wet environment it’s even worse so it’s not unreasonable to see that a peroxide cured product will match the cable life expectancy and and those are predicted out of 40 years so I certainly don’t see any problems with those as far as the life expectancy of the grease I don’t have an answer for that I’m sorry I don’t have any accelerated data out past a few years so maybe someone else that’s on the webinar may have some information that they could pass along hopefully somebody does now you spend that in an email and what has everybody lel we’re going to take the rest of the question right now I’ll turn it back at legend okay thanks quietly thank you all thank everyone notices anything laying day please make sure that you can play with your vet now that the webinar finishing and if you have any additional questions please feel free to contact me my email address is on the screen rings although you probably already have it from your invitation so again thank you very much

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