The above Ad will no longer appear after you Sign Up for Free!

What's wrong with this picture

Discussion in 'Question of the Day' started by Grog12, Feb 18, 2008.

  1. Grog12

    Grog12 CBMod CB Mods Premium Member

    Messages:
    2,615
    Likes Received:
    172
    Location:
    Denver, CO
    Wall mounted 20amp stage pin connectors...what's wrong with this picture (as in what made the mess)?
    [​IMG]
     
  2. gafftapegreenia

    gafftapegreenia CBMod CB Mods

    Messages:
    4,349
    Likes Received:
    486
    Occupation:
    Prop-tart
    Location:
    Chicago
    Insulated terminals?
     
  3. Grog12

    Grog12 CBMod CB Mods Premium Member

    Messages:
    2,615
    Likes Received:
    172
    Location:
    Denver, CO
    Close, can you be more specific?
     
  4. gafftapegreenia

    gafftapegreenia CBMod CB Mods

    Messages:
    4,349
    Likes Received:
    486
    Occupation:
    Prop-tart
    Location:
    Chicago
    The crimp terminals have insulation on them, I suspect this melted.

    I recently replaced a set of floor pocket outlets with charred neutrals as well. Why is it so common, it seems.
     
  5. Charc

    Charc Well-Known Member

    Messages:
    1,850
    Likes Received:
    46
    Is that why uninsulated terminals are preferable? Or is it a space issue in some 2P&G connectors?
     
  6. ship

    ship Senior Team Emeritus Premium Member

    Messages:
    6,083
    Likes Received:
    371
    Location:
    Illinois
    shouldn't get up hot enough to melt the insulation off a insulated terminal.

    Might want to look into three or more other causes that caused this localized overheating problem.
     
  7. gafftapegreenia

    gafftapegreenia CBMod CB Mods

    Messages:
    4,349
    Likes Received:
    486
    Occupation:
    Prop-tart
    Location:
    Chicago
    Poor pin contact causing arcing.

    Loose screw terminals in the male plug.

    Loose screws on the female outlet.
     
  8. icewolf08

    icewolf08 CBMod CB Mods

    Messages:
    4,061
    Likes Received:
    655
    Occupation:
    Controls Technician - TAIT Towers
    Location:
    Lititz, PA
    Well it doesn't look like it was an insulation problem, but the e-tape sure seems to have melted.
     
  9. soundman

    soundman Well-Known Member

    Messages:
    1,085
    Likes Received:
    115
    Location:
    Nashville TN
    From what I can see in the picture the damage is more to the crimp connector than the screw terminal, is it possible that the crimp was done loosely and that cause arcing under the insulation which then melted resulting in a charred mess.

    Let me guess these were taken from some US floor pockets right around where a cyc would go...
     
  10. gafftapegreenia

    gafftapegreenia CBMod CB Mods

    Messages:
    4,349
    Likes Received:
    486
    Occupation:
    Prop-tart
    Location:
    Chicago
    I considered poor crimping as well.

    What is it with US floor pockets near the cyc having socket issues. Must be something to do with heavy use and large loads. Might also have to do with lateral pressure being put on the male plug itself. Not exactly sure how to describe it, but when the door of a floor pocket closed it puts a rather tight angle on the cable coming out of it, which puts pressure on the connection. I surmise all of this must add up to failure.

    Of course none of this matters, as Grog said these came from a wall pocket.
     
  11. Grog12

    Grog12 CBMod CB Mods Premium Member

    Messages:
    2,615
    Likes Received:
    172
    Location:
    Denver, CO
    The ring terminal has melted but why?

    Namely because these aren't "industrial" ring terminals. Meaning they aren't rated for over 600 watts. When you plug 1000w-2000w into said plug the weakest link fails first.
     
  12. mbandgeek

    mbandgeek Active Member

    Messages:
    480
    Likes Received:
    9
    Location:
    North Carolina
    Was the ground originally cut?

    If so, It could just be a voltage spike, that had nowhere else to go.
     
  13. porkchop

    porkchop Well-Known Member

    Messages:
    1,753
    Likes Received:
    415
    Location:
    Vegas
    I hope the ground wasn't cut to begin with. If that's the case poor installation is your problem. But assuming that it wasn't cut if it was worked on recently I would go with poor crimping on the connector if it's a terminal thats been there for a while it's probably a screw that has worked loose and arced. I know these have been said but the time line mentally makes the trouble shooting easier to prevent it from happening again. Never would have thought of connecter load rating, good point though.
     
  14. ship

    ship Senior Team Emeritus Premium Member

    Messages:
    6,083
    Likes Received:
    371
    Location:
    Illinois
    I'm noting some discoloring of the screw terminals due to heat which could indicate a number of things including loose screw terminals. However, given these were mounted in a perminant install condition, and not say bouncing around in the back of a truck it is not as likely the wiring wiggling about loosened a screw terminal.

    On the other hand, I'm not famailar with a wattage rating of ring terminals. Would be an interesting thing to look into and often I have questioned it but as yet other than voltage ratings I don't know of a wattage rating. Plug is rated for 2,400w, wire in theory is also rated at that if 12ga. Ring terminal looks to have a good crimp (broadly viewed and subject for question).

    A few things could be. Amongst them, heat can transfer thru the pins of a male plug into the wiring of a female socket. However, this heat transfer is normally more localized to single pins only not all including heat damage seen on the ground wire screw. This might limit it to something between the female receptacle screw terminal and the wiring going there, if not possibly box fill capacity. Amongst other things.
     
  15. TimMiller

    TimMiller Well-Known Member

    Messages:
    1,293
    Likes Received:
    82
    Location:
    Houston, Tx
    You have to watch it with those crimp terminals. Next time you go to home depot look at the wattage rating on them. They are ususally rated for 600-1200 watts. You need the heavy duty ones. Also do not use regular crimp terminals on the ceramics in par cans. They melt and catch on fire. I use the high temp crimp terminals from 3M. They are rated for 300 degrees C in which i'm sure a par can will not be a par can anymore at 300 deg C. I also use ratchet crimpers with all crimp connections. You can buy ratchet crimpers for around 30 bucks. I bought the paladen 1300 series with the interchangeable dies and they ran me around 70 if i remember correctly.
     
    Grog12 likes this.
  16. ship

    ship Senior Team Emeritus Premium Member

    Messages:
    6,083
    Likes Received:
    371
    Location:
    Illinois
    Are you sure that is not the voltage rating? Not ever noted a wattage rating on a ring terminal but I will check further at the home center and with 3M as opposed to with McMaster on line. If it is voltage, at 120v all is good as my point, more a question of the heat of a fixture in agreeing about going high temp. but not about the details.

    Good point on butt splices persay in cans or even butt splices, but also a question of how you insulate those high temperature butt splices that will play a factor given there is no such thing as a insulated high temperature crimp of any type rated at that temperature I'm aware of. Make that 600 or 900C for the splice/crimp terminal. While 200C wire is normally (normally) fine for a lighting fixture in wire, what attaches to the terminals of a lamp or might in splice to a lamp touch that lamp given 300C is only 572F, could easily be overheated by a say 650w lamp measuring in best I could do 500F temperature reading of it and other wattages will be more or less. Besides that, high temp terminals are the above I believe 600C at least which is normally fine.

    Got some ratcheting crimp tools also, they do the job but I prefer hand Stakon type crimpers in having better jaw selections for material displacement - this when properly crimped. Just had to correct on of my assistants today for over tensioning a terminal as opposed to the normal under crimping of them. The ratcheting crimpers on the other hand are easier to use and ensure that they won't reliese until fully crimped. That's a good thing but still tug hard on the wire crimped, even if the proper non-insulated crimp jaws for them when set for the proper gauge of wire seem a bit overly round in more crushing than displacing material in the crimp. Never use the "insulated" crimp jaws, they crush and don't displace. My Palidin tools are used mostly for ferrule crimp tools.

    Perhaps agree to disagree in me now having some stuff to have a look at.
     
  17. TimMiller

    TimMiller Well-Known Member

    Messages:
    1,293
    Likes Received:
    82
    Location:
    Houston, Tx
    Most crimp terminals are rated between 500-1000V. I'll go out in the shop tomm and dig out the high temp and let yall know. I will also dig out the regular crimp terminals.
     
  18. Grog12

    Grog12 CBMod CB Mods Premium Member

    Messages:
    2,615
    Likes Received:
    172
    Location:
    Denver, CO
    This is the exact reason I started looking at all of my crimps and wire nuts in the theatre. I've had many many many melt/catch on fire. Especially with PAR cans.
     
  19. gaffer240

    gaffer240 Member

    Messages:
    26
    Likes Received:
    0
    Location:
    Beaufort, SC
    Think y'all have touched on most possible reasons for the damage. I have had connecters just melt down for no obvious reason. I usually suspect loose screws. Who knows what a dying lamp might create when the filiment shifts. Super bright, and a short explosive life.:lol:

    Gorg 12, there is a fairly easy way to deal with high temp wire nuts. Your nearest appliance parts store should have some high temparture ceramic wire nuts.

    I sort of learned this the hard way, elctrical tape and plastic wirenuts should never be used inside a lamp housing.
     
    Last edited: Mar 5, 2008
  20. ship

    ship Senior Team Emeritus Premium Member

    Messages:
    6,083
    Likes Received:
    371
    Location:
    Illinois
    Don't think it was inside a fixture this problem or caused by any form of lamp heat, but also don't ever recommend of high temperature wire nuts inside a fixture. As with normal wire nuts, the tendancy is for the wire nut to become loose and fall off in exposing the conductors within - this in addition to strands of wire being cut while screwing the wire nut tight. Current means expansion and contraction, this also means settling of the individual strands of wire to where there is less tension on them. Could have done all properly but still wind up with a loose connection which could even further mean a loose connection that has resistance thus more heat. High temperature wire nuts to solve heat / connectivity problems other than inside a high temperature situation in solving heat problems in general won't help a resistance problem in better conducting, installing the proper either high high temperature butt splice that's high temperature taped or a proper set screw wire nut is the solution for this. This given a high temperature application to start with, and one that is portable and not installed on a wall that don't vibrate and not inside a wall box.

    Even on a Altman Mini Cyc or audience blinder, my tendancy is to replace such things as ceramic wire nuts with High Temperature Set Screw wire nuts which don't fall off and do ensure a good connection. Insert the strands of wire into a ferrule, if necessary crimp that ferrule so as to fit inside the wire nut, than tighten the set screw down onto the ferrule just as if installing a wire into a stage pin set screw. Afterwards install the high temperature wire nut cap on the set screw cap and one inch lower than this band together the conductors with high temperature fiberglass electrical tape so as to provide a strain relief. Don't wrap the wire nut itself - wrapped wire nuts make me suspicious in what is wrong inside it. Instead it should just be a band of tape providing strain relief without anything suspicious about it thus spaced away from the wire nut assembly.

    Such set screw wire nuts of course should not be used on solid building wire but solid wire is not rated for any high temperatures anyway. Inside an electrical box which does not get moved about or travel cross country inside a truck, there is little chance for a wire nut to wiggle free. Or if a box is traveling about the country but is not exposed to heat from a lamp, a simple cap spice or any other insulated splice would be fine for use. This given solid core wire is not suitable for portable wiring thus is not a factor.

    Otherwise when doing an in-line splice I'll use a high temperature butt splice and wrap it and 3/4" of conductor leading into it with three layers of fiberglass electrical tape. This if not doing an old school solder splice also wrapped in fiberglass electrical tape.

    Overall, no direct heat, not portable, nothing wrong with a wire nut - though one would tend to instead put the wire inside the screw terminal. On the other hand if solid core wire feeding the outlet which don't crimp or work with set screws too well, a normal wire nut would be fine in splicing a stranded wire that goes to the receptacle to that solid core wire.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice