Problems with 60-amp Bates Connectors


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I'm curious - has anyone had any problems with new Bates Connectors? We've got a batch of cables that were purchased 4 years ago. We've rarely used them since we mostly do standard lighting (not the heavy-duty stuff). What has happened is that the strain reliefs have caused undue pressure on the screw threadings for all five case screws, and the slightest bit of twisting or impact causes the threading to completely break. We've got thirty connectors that are completely useless, and another 20-40 that have symptoms (stress fractures). Again, I'd understand it if we were abusing them, but mostly we just move them around from one place to another. Any thoughts? The base part of the connector is the only part that has gone bad, but the rest of the connector is perfect.

BTW - we didn't assemble these 60-amp connectors, just to clarify.

Definately sounds like a manufacturing issue to me. I know bates connectors can get cracked or exhibit the type stress you are describing if they are dropped repeatedly, or dropped just right, so that the top edge hits the ground just right.... But if you haven't been using them and no one has been making nunchakas out of them < 2' jumpers make great nunchakas> I'd double check with the manufacturer and see if they had a bad batch of plastic or an over ambitious assembler. What manufacture are they ?
Sounds like the screws were over torqued during assembly or the adjustable stress relief inserts were sized wrong. You might get some help from Lex Products.
I agree with Bill on the plug answer in general but note in the post exclusively calling them “Bates” plugs a potential for calling them a “Batesplug as per “Leko” type slang possibility as opposed to another specific brand they could possibly be.

There is a possibility by way of description of the problem that unless one is not very specific in citing the specific Mancuro/Advanced Devices/Bates brand, that these plugs especially if old or in general if using “Bates” as a description of a 60A 2P&G or Stage Pin or Slip Connector also slang or definition are of another brand of plug which would necessitate knowing what actual brand they are before describing a solution. This especially of the commonly found middle ?c1980's version from Union Connector that for me is frequently suspect for seeing it a lot in for repair or replacement. It’s frequency in seeing is what raises the question or at least holding one step back from attributing the problem with that specific brand/design style. Such a specific fix for a Bates plug below will have a potential solution that will work without spending much money but might differ if of another brand in what to do or use. But I defiantly agree if a Bates plug or in general on Bill’s assessment of over tensioning or wrong strain relief, as the cause of the stripping at the strain relief. Most likely not at the strain relief an age or application type of thing unless say soaked in say DF-50 fluid as a common thing or out in the sun all day. If as Bill describes for cause, any and all plugs would have the same problem when over tensioned.

If in actuality the middle 60A version of Union Connector I have a lot of in “failed spectacular” condition on my wall of shame - this by way of melt down as opposed to failed/broken strain relief, stripped screw as also common with them. If the case of a 1980's/1990's Union plug as very popular at the time, the solution might be different such as making some into spare parts and replacing others. Always hate to spend money and try not to where possible but on the other hand at times it’s necessary and or some while expensive thing has paid for itself and is due for replacement.

This as opposed to other older Union plugs which would have different solutions similar to the solution on newer plugs. They, this middle generation but common Union plug for a 60A plug are very commonly found on 1980's and 1990's equipment. Some very good design ideas on it such as the contact/arc shield around the female end, and I believe if remembering correctly, the off center double set screw to it’s pins but as a plug, it’s fairly brittle and lacking in heat resistance. This melting down is both a good and bad thing in that it’s potentially better for the plug to melt than continue to function even if in a failed condition. The Bates and Rosco plugs would be the next best from what I observe after this in potentially melting down if bad given an agreement of melting down of the plug as a good indication of a say loose set screw as opposed to a loose set screw at times being in contentious use over a long period of time and possibly never knowing unless one touches a really hot plug or possibly one that fails during show before it is shown to be wee bit melting on welded to the female by way of use - after the show. Worked even if melting a wee bit for the show but as a concept will never work again until replaced after removed. That’s good for a temporary show but not so much use for a permanent install perhaps. I’m on the fence about this two and or three choices for plug design see below with an alternate solution in finding those that would fail before it’s an issue.

From what I can tell in my collection of odd, old and interesting is three generations of Union 60A Connector (or those probably made by Union but with another name on them such as Grand Stage) in the 15, 20, 30, 60 and 100A versions be it from Kliegl or Union two or three pin. Got some really odd ball ones in the collection of styles of stage pin plug in design, some two pin with a hole for a ground but no socket, of course those with single hole and two or three holes as opposed to one hole for the cables to exit, and a really small 20A one with only “G” for ground stamped on it. Various molded ones, various Bakelite verses typical Union or Kliegl fiber cast ones etc. Don’t have any of the late 1980's “locking” stage pins unfortunately as a hole in the collection at this point though I remember them very well. Of 60A, the old ones possibly from Union no doubt made for Kliegl, but possibly not in Kliegl potentially making their own. These old 60A ones with the aluminum strap strain relief and solid casting as opposed to a problematic second generation 5/32" thick tubular shape could be just fine as a plug 40+ years later and still working as long as the cable fed from it were replaced and it’s a three pin instead of two pin plug.

I would trust a 1960's plug without a problem. It’s the “upgraded” tubular ones that seem to melt down most easily or in many cases break not strip the strain relief. In checking the website, Union Connector seems to have a newer design that is in line with modern preferences from Lex and TMB and should be just fine - my current preferred style also. Interesting that Creative Stage Lighting as normally another alternative does not have a 60A version. Might be other brands/versions of 60A on the market beyond these.

Rosco and Bates seem to have a similar design of 60A plug in a more like the normal 20A bates plug in hollow casting and material style. This design works fine as a plug, I have lots of the Bates 60A plug in stock without problems over a number of years of service. Specifically in confirming the observation, I have never seen a failed strain relief on this brand before. It’s design advantage is the ability to adjust it’s strain relief for a variety of cable types or applications. You can also replace individual pins on it should it be necessary as opposed to replacing the entire plug. This concept is an important design choice to weigh in to some extent given once a 60A plug fails often it really fails in a big way but at some points will only need a part or a pin replaced. This as opposed to the current Union, Lex or TMB versions styled after an older type of Union channeled molded plug design. Solid casting of plug with pin’s permanently mounted and a cover. Very rugged all be it but not made up of replaceable parts or even standardized covers between the male and female versions. Between the two types of plug, two plugs to weigh equally in both working well and UL listed for both doing so well in all cases. Believe IESTA just also came out with a specification that standardizes these plugs so as to limit the chance that a fraction of an inch difference between brands might cause problems in inter brand connectivity. Never seen that problem so far but as possible a problem should your brand in use be X design and a brand new Y and to spec. design be a different dimension in fitting your old stuff to new plugs.

You have 60A plugs and gear, you are big budget already eat the cost as a necessity if necessary. Got a big rear to chew with the bean counters where needed is saved for situations like this but only if necessary. It’s possible spending money will become a project in expense should the new plugs not fit so well with the old ones, or if by your choice replacement in being “factory” thus completely complaint with code be the best solution both in my below solution and in a question of should new plugs be different in spacing and dia. Specification, what’s new not working so well with the old plugs. Probably not your condition and I’m yet to see a new plug that would not mate with a old one but something to verify in testing before you get too far in something I remember reading thus necessity for a standard in. Such a discussion if searched for would be part of the Stagecraft Digest past discussions - I’m fairly certain it’s a discussion on a ESTA standard for 60A stage pin and not CamLoc style plugs. ESTA website should also have this standard than listed. This as opposed to “CamLoc” from Leviton by way of bad lot number the male in casting I very specifically got one month which seems to be short of wee micron of an inch fiber wheel grinding, have problems mating up with even the same brand of female by way of at least one lot number I got at one point. Good plugs, never had a problem before, one bad lot however is still a bad thing. Strange thing, just a fraction of an inch and the male plugs won’t sleeve with the females of the same lot number. Seen it before by way of brands with different OD’s of the pin but never by way of grinded flat part of it causing the problem. Must remember to remind my assistant to verify the plugs on all the CamLoc’s he was doing today given this bad lot number in our inventory. Sending an E-Mail reminder momentarily as I write. That would with the Cam Loc large types of connector in not being standard as per a Edison, Twist or Stage don’t have problems with problem on the larger types of over 50A plug.

What ever the case with CamLoc plugs in between brands, lots of design styles and at times between brands or even within a brand not always being similar in mating up, I believe they are not yet a ESTA standard even with the single conductor draft standard about to become a rule. 60A by memory is now and might be a problem for your system in even if you buy the same brand, what was manufactured yesterday might not match up by way of that micron of an inch specification or lot number mistake with that of what you currently have. Most likely there will not be a problem and I have never noted one but it’s possible due to what I remember in discussion off Stagecraft. This will be something to consider if you buy new plugs. While it should not these days matter the brand you choose, ensure they match up with your old plugs before calling the problem solved.

Had a chance today to look briefly at a Bates brand of stage pin plug though not enough to take it apart and have a look much at it. Upon refresher of sight of it, I know or am fairly certain a memory of it using a 1/4-20x3/4" Phillips flat head screw with a black oxide coating. This 1/4-20 screw if having stripped in the plastic would be a defiant problem in being hard to replace the screw with a different one - also a screw fairly hard to make strip. As a third option for why it failed as a strain relief, it’s possible in this due to power tool driving it and not having it’s clutch setting set to click before over driving and stripping out the hole. Yep, nice, fast and easy to use a power tool for assembly of a plug - be suspect of the pin terminals now given this possibility. Stripped here could also be bad on all other screw terminals. Never trust a cordless tool for what your hand or a torque wrench does best in finalizing the tension. IF you find one thing suspicious about a plug, be suspicious about all that plug and both ends of it.

Unlike with the 20A Bates plug where by if the strain relief screws strip you can simply install (by memory in what size it is and guessing it’s #10), some 10-16 as replacement or 10-14 Pan head Phillips for Plastics screws in the stripped holes and have them work well. Way back when last I bought two sizes, perhaps it was one of the two than a Low/High more normal screw of the same stock which otherwise worked once the sharp point was cut off. Don’t remember other than I have two screws that work well at least for a 20A version of this plug once stripped in hole.

By NEC specification, you are not allowed to modify a plug so it might mean you cannot once the strain relief has stripped out attempt to use a different threaded screw or epoxy the hole in making it useful again. Than again it’s the strain releif and might if done well be acceptable. I mention epoxy or other glues to make the hole new again as the second alternative as an option.

When the Lex Products Socapex Twofers with their molded bodies have the screws holding the panel mount plugs fail, I squart some Gorilla glue into the holes and either re-install the screws provided or if shot, do other similar screws back into the stripped and now glued hole. Works really well in what is a screw into something rubber like thus at times less sufficient to hold the plug onto it than a cable attached to that twofer perhaps tugged on by a chain hoist.

Gorilla Glue might not be a solution for the plastic on a Bates plug, might work well but might not. There is lots of adhesive products on the market between epoxies and latex form adhesives which will bond well with plastic in it’s various forms. As opposed to worrying about bonding the screw to the plastic, get first a glue that will bond to the plastic. Fill in the stripped hole, than drill it for the screw and thread the screw in afresh.

Such a repair would not be letter of the NEC compliant in modifying the plug but would be compliant as an opinion if the work were professional in doing and well thought out in rational and use. Can’t think of a 1/4-20 screw alternative that would as opposed to the screw on a 20A bates plug work well enough. I would in keeping it looking finished product and factory probably glue the hole than start over, or use an expanding glue such as the Gorilla Glue and glue the screw into place.

This as opposed to the more hack third option which could also work but look less nice. The strain relief screw fails within the base of the plug? Drill it, insert a longer screw and use a nut on the opposing side. This would work but not look as good thus be near as intent of code compliant. This would be a solution to use on the job site only.

Now for other notes now that you are giving time to these plugs.

At least every other year if not once every year, I ensure that all 60A cables in the inventory or each rented 60A plug used is taken apart and verified for it’s torque amongst other things to look at. Main reason for these plugs going bad - given there is no reason for a strain relief that’s over tensioned given people can read directions, is the set screws attaching wire to pin become loose. When these plugs go bad, they go bad in a big way so be very careful with them and set up a program of annual inspection for them.

First verify the strain relief is both sufficient in wires not wiggling within them or too tight they are forcing insulation out of the way. Over the years OD of cable has changed some at times with specific cable types. This could mean that a type SO cable now in a plug designed for a type S cable of yesterday won’t clamp as well on it or even be proper short of friction tape added. Nothing but friction tape either - electrical tape don’t work the same and Gaffers tape also not working as well is not rated for this purpose.

Also verify that the strain relief is clamping down (though not too tight) on the outer jacket of the cable and not the conductors. Should be at least 1/4" of outer jacket inside of the plug and in no cases should that cable strain relief clamp down on the conductors. If it does or if that strain relief was too tight by way of insulation between conductors losing say more than at most 1/3 of it’s inner conductor insulation at the clamping point as a balance between something too tight and too loose, cut the cable and re-install the plug.

Next verify that there is no dry rot or heat problems with the conductors or outer jacket, as well as twisting/coiling problems such as a seeming knot of wire inside the jacket right outside the plug. That cable going into the plug should be just as round at where or just before it goes into the plug as on the main part of the jacket. Discrepancies in coiling or seeming knots in the cable near the plug is cause to cut and re-install the plug behind this problem or replace the cable.

Check the rubber jacket on the cable for dry rot, cuts and as above problems in coiling or bunching and knots. That cable should be free of knots, cuts - especially cuts deep enough to see copper and in general knots or twists in it. It also when flexed in a sharp angle should not show any cracking on it’s outer jacket. Cracking means a dry rot in need of replacement. You should also be able to read the manufacture of the cable’s markings by way of gauge, voltage, type, brand and class on the cable jacket as a rule repeated once per foot. You don’t see this, it gets replaced as no longer code compliant on any cable but specifically this probably 6/3 cable type.

As with the above on dry rot or heat damage, once inside the plug check for heat and or dry rot damage to inner conductors by way of flexing and observation for say rubber that has heat damage. Conductors with heat damage will often when flexed have insulation covering them flex off in flakes or even have a brown coloring to them. At very least, an old and failed cable dielectrically will crack when bent.

Quick checks next are to make sure the cable has ferrules or at least copper foil between conductor and set screw and that the neutral is in the center and not the ground conductor. No ferrule or at least copper wrap, bad Karma and something to immediately replace. 60A plugs must have the neutral in the center - don’t be fooled by 20A stage pin plug habit, but given the habit it’s something to ensure was not done badly especially by those who don’t read strain relief directions. Third easy check is to see a parallel gap between the sides of each pin on a plug. As with a 20A plug that needs that parallel slot in the pin in order to expect it will fit properly in a socket, you on this cable had at best also inspect the gapping of the pin. Too bad for the most part Pinsplitter type I 20A/60A aluminum pin splitters are not as easy to get. +

There is still suppliers of the 60A version of this, but they are not as frequent as the 20A only version supplier. All Bulbs possibly, BMI in last known selling it or also in their own version described as “Mutt” - possibly a type I, Premiere Stage Lighting, and Barbizon are the only links I have as of a few years ago to a 60A stage pin - pin splitter. The rest are the plastic type II that only does 20A. Bought mine like 15 years ago thru Design Lab Chicago, but this was long before the Type II came out or as I once was told, the person that made the type I retired given stage lore and possibly not much of fact.

Finally and the main reason to check the plug is the tension of screw terminal of the pin in tension on the conductor. It’s against NEC practice to go into a circuit breaker and inspect the tension in making it tighter later, this or over-tensioning it. That’s all fine for a permanent install especially on solid wire, don’t work on show cable within a 60A plug. These cables and I don’t know why beyond settling of the individual strands of wire that they do commonly for some reason loose tension and need that specified I believe it by memory to be 25# per square inch tension yearly or you will get a melt down but it’s important yearly if used lots or at least every other year if not as much to tension or torque.

I highly recommend for your yearly test of set screw torque purchasing a at very least Stanley/Pronto McMaster Carr #85555a114 reversable torque wrench and add what 1/4 drive fittings your terminals are to it to ensure you are torqued properly especially now in starting the process, and in a shop capital tool/investment a tool to use over the years for ensuring it’s the case of torque later during the inspection. If necessary offer to the bean counter that they can hold onto this tool other than for the yearly inspection and or any plugs that need to be installed so as to ensure it won’t become stolen. The proper torque on a 60A plug I have found to be monumental over that of a higher amperage and lower amperage plug in being proper over the years. This especially if a plug that’s traveling about and wiggling about in the back of a semi-truck trailer on the way to the show which would tend to settle individual strands and conductors into being ever so much loose between shop and show.

I thus stress that if you are giving attention to fixtures and cable of this type, you spend a bit more time with them if not already policy in ensuring it’s in good shape. This beyond getting out the inspection mirror and flash light in examining the say 5Kw Fresnels to ensure both lamp base and wiring to it is in good shape. Also yank the lamp each and every time before use in inspecting it, it’s filament and lamp base pins. Lamp base pins are often a good indication of lamp base in addition to if loose a warning of a future pinch seal problem. If two piece lamp base to the lamp porcelain, often a stainless steel hose clamp as supplement to hold the two pieces together can save the day. Monitor the cracks in the lamp base cement, missing chunks that can at times be filled by McMaster #7551a23 putty. This as long as in often the case, as long as the silica sand filler often also the case has not leaked out too much. 5Kw DPY lamps, just expensive enough to take care with, not expensive enough to have a cow over when they fail given you tried your best.

Anyway on the 60A plug, and fixtures attached to them, I hope this is good info on what to further check. No matter the cable type, if I see some one thing wrong with it, dependant upon how simple mistake in doing it I see, that raises the level of suspicion on other things wrong I might see within it thus the more likely I will inspect the whole thing beyond what is normal and easily observed. In your case, if it’s failed strain relief on a Bates brand plug, that is a very much expected to be installer and not defect cause. Be very worried about what’s on the outside and even more about what’s on the inside. 50/50% chance I give it if bad strain relief if this is a replacement plug that those installing it did not use ferrules much less a torque wrench inside.

A few weeks ago I had someone go thru all the 60A plugs going out on a show both rented and ours. While a huge pain in the rear he was correct in complaining about, once he got into them and started seeing the necessity no matter the brand or who did the plug, the necessity was evident. This including on plugs that had just been torqued perhaps not last year but for sure the year before.

It might seem troublesome the concept of constantly re-torquing a screw terminal in every time it's done making it tighter thus more resistant to current flow. That's agreed, but a good torque wrench with the right setting should not put undoo pressure on the screw terminal if the correct tension and some if not most certainly were. Still no matter the brand of plug, some were loose and taking the time saved time on the jobsite. When the show came back, given the level of inspection of fixture and cable, there was no issues as opposed to in the past where it would come back bad if not fail on the job site. Degree of inspection and maintinence is frequently the difference especially on 60A plugs and 5Kw gear. This as opposed to some E-Bay 5K and 10K Fresnels I once was provided that literally had insulation flaking off the wires and lamp bases crumbling at the touch but "servicable."
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