I'm looking for high temp rated electrical tape or equivalent suitable for use on frayed lamp cords.
Just an audio guy here trying to help a High School before they burn down the auditorium, if I'm not asking the right question here please steer me right.
Given the concern about this being high school kids that without very proper supervision should not even in masse be messing with replacing fixture whips at that level of experience - no matter how simple it would seem, I will go into further detail about what I accept as proper repairs much less techniques. In any case, fiberglass electrical tape as an option for taping up a lamp whip as opposed to just electrical tape is ugly but at least just as safe a solution if not heat resistant in fulfilling that part of the goal. Point will be if it’s a temporary repair to get the show up and running in which case electrical tape suffices as long as the cord does not get hot, but neither is a proper or permanent repair.
In reviewing the question posted, “help a High School before they burn down the auditorium”, I think this is more a general statement of concern than as specific as “Given that the poster is discussing fire” to which TGGT heat wire is about the only solution but not very flexible as a cord whip thus will no doubt require replacement in a few years also. This however is more a concern about frayed lamp cords in a theater than melted wires much less catching fire in any other way than abraded lamp cord shorting against something. What seems to be frayed wires to me it at least seems to be what we all commonly see in the fiberglass sleeving covering the conductors looking like hell. What condition the inner conductors is in and where these cuts are is up for more detail before any repair is attempted however. The lamp cord might look like hell and look unsafe but also be just fine.
What ever we think he is talking about in any case will not be clear until he posts again with more details so any of us can provide the information requested as to what specifically he is concerned about. For the most part I expect all of us would have the same replace the cord solutions in most instances as eats up our own budgets. Who is qualified to do so given proper supervision also is up for debate. “Hmm, what’s this mica thing” behind the contacts, this in being later forgotten to add to the lamp base by a professional lighting technician - meaning someone paid to preform the task they said they both could and had the ability to do was forgotten at one point where I work on a lot of fixtures, and such fixtures shorting out two years later is still a problem in just finding what this professional worked on long after the professional tech person is gone. Short of proper supervision, group effort does not replace someone that knows the why of each component much less would with experience and training have repaired these frayed lamp cords before they got to the point the sound tech became concerned about burning down the building because of them. At this point repairs must be taken to somewhere and to someone that understands the why in playing it safe. Too bad the old time TD’s in high school are only those often it would seem that had acting class in college - many exceptions to this statement but the norm very often. This is our next generation of tech person you trust on tour.
I do agree with you about tape as a “half ass” repair in many circumstances - depending upon the type of repair done, technique used and who is doing it, and brand of tapes. There is some qualified people doing such repairs that do look good and are using the repair under the right circumstances after all, it’s just a question of who actually did the repair and since there is no signature on the repair it’s really hard to tell who did the repair.
I do know my repairs are permanent and am well respected for such repairs, but I include more than just tape amongst the lineman splicing techniques I follow on at least cable repairs. Perhaps once a year you re-coat the cable with more cable paint over the outer coating of the best electrical tape I can find, but it’s than good to go and very safe even for feeder. This after cleaning the cable with naphtha, using rubber adhesive to attach friction tape over big areas otherwise just rubber splicing tape above the glue, another layer of glue than Super 33 electrical tape plus cable paint over it all. Very specific in amount of layers etc. it is now water tight in addition to abrasion resistant. Such a repair to cable when tapered properly is barely noticeable and just as proper as the original cable jacket electrically. A electrical tape repair over cable just makes me suspicious as to what’s under it and who certified that the problem was safe now. Large difference here, in what’s done on the road verses what’s professionally repaired permanently that will last a tour or three.
Repairs due to heat are different however and normally something to be cut out and replaced thus the repair as advised by you. However given it’s lamp cords we are talking about, 12/3 SJOOW is certainly not something to use to replace on a whip. SJOOW wire is rated for 90C., and in all but low wattage instruments, even the most cheap of cable whips/lamp cord such as VDE are rated for at least 105C. if not 200 or 250C at times. SJOOW by code also is only rated for use on stage in lengths of 3' and under (your pigtail or in other types of fan-outs) so even if we were talking about extension cords, such cable would not be a adequate replacement for an extension cord once cut or melted. In other words, it’s going to get a little more expensive in the basic math much less experience level required.
This is very dependant upon what fixtures are melting or “Fraying” because given the fixtures come with heat wire - especially in the case of stage lighting fixtures that come most often with 200C. wire whips, it should be somewhat rare that the lamp cords are melting especially given stage lighting equipment given normally #0 fiberglass sleeved SF-2 wire of 16AWG. at $0.10 to say $0.50 or more per foot each conductor including the ground, plus about $0.25 to $1.28 per foot for the fiberglass sleeving. Normally however given stage lighting equipment such wire should not be melting down however even if it touches the fixture. Such heat wire does fray fairly easily and commonly however.
Given it has, than you also have to factor in if it’s special lamp base attached heat wire or not such as in a P-28s type lamp base - Medium Pre-Focus on a Fresnel or Screw type base also commonly having screw terminals, in which case if not such a lamp base with screw terminals necessitating other wiring options at the termination such as high temperature ring terminals, you need to replace the lamp base etc. by way of factory specification and provided for you as the lamp base including whip. In most instances replacement of the entire lamp base or lamp base contact assembly is not a bad idea because they do wear out - a topic of inspection for another day.
Short of being a qualified service center having mastered high temperature splicing techniques similar to how I do so in having found alternatives and having tested such theories in what works, or how Altman splices their cyc lights using that high temperature fiberglass tape given the somewhat hard to do properly solder line splice of adding a conductor to a feed thru wire while not necessary in this case of a butt splice and as such can be replaced by a high temperature crimp, in addition to other factories having engineers doing the math and choosing the materials used; - such splicing that while it saves time is almost as expensive often to do properly and otherwise is not usually within the ability to safely spice by even normal and well trained tech people above a nylon cap splice which might serve for a smaller PAR Can but otherwise is not acceptable to be within the PAR 64 or a lamp cap of other lighting fixtures. Just splicing a piece of 12/3 SJ wire to a lamp base wire in 16 ga. is not an acceptable option in that even if you know about step down 12ga to 16ga butt splices and have the tools to properly crimp them much less afterwards insulate them, they are not rated for high temperature thus not to be used within a lamp cap. 12/3 SJ type wire should never be used for fixture cord. Anyone that has not mastered and spend hours in testing high temperature splicing is by far better off just simply replacing the lamp base than attempting to splice to it given even the lamp base is even worth saving.
S-4 lamp cord whips list in price from $7.28 to $20.00 each for instance and you can’t just buy the crimp terminals in adding it to a shorter wire or replaced, even better wire/conductor at a cheaper cost. Might be something anyone should be able to just crimp to the wire, but ETC sells the entire whip as a done deal and you have to replace the entire thing given frayed cords - unless of course you can cut the cord where it is fraying and just have a shorter whip. Same basic price range for other types of lamp bases where the cord is directly attached to the lamp base such as on a Altman type TP-22 lamp base. Were I interested in hack, I might be able to splice a new cord to the lamp base, but I don’t do hack due to the liability of what I now am responsible for, others not trained in such techniques above might not have as safe of results. If the question comes up in replacing the lamp base and whip attached to it, it is always safest and fastest in man-hours to just replace the lamp base and whip. Amazing how many yellow home owner grade wire nuts you find in household repaired lighting fixtures with SJ type cable spliced into the lamp base cable. Also not unusual that opposing conductors will melt right thru the wire nut and short. Splicing within a cord is never permissible - major safety and NEC forepaw. Within the lamp cap, it is only permissible at times and only with the proper materials.
The question really is what is seeming to be fraying/abased/exposed including also as the post lacked detail if it’s even asbestos heat wire lamp cords with flaking wires and conductors exposed and also looking like hell, amongst other concerns of the specific type of lamp cord. It is very common on the more modern lighting fixtures for the fiberglass sleeving protecting the conductors to fray and look really bad but still for the inner conductors to be safe. This short of small holes in the fiberglass sleeving which can be repaired with Plyobond 20 in mending the frayed fiberglass back together and preventing the hole from opening up further, necessitates replacement of the fiberglass sleeve only but not the lamp whip if in decent condition. Holes the size of a dime however often can just be glued shut or in other situations be taped over with electrical tape in offering similar protection. The problem is that the electrical tape will melt if it touches the fixture thus probably the posted question in finding a high temperature electrical tape. It will also look like hell if not start to peel up and become gooey over time. I use heat shrink company labels to mark our fixtures as belonging to us, and it’s not unusual for me to have someone remove the old shrink tube label and move it up to cover the hole if it’s otherwise in good condition. This saves if only one hole larger than the glue can repair, the necessity for a time at least for replacing the fiberglass sleeving because under the company heat shrink label is the damage is now sufficiently protected and it is not seen otherwise in looking like a electrical tape repair hell.
At this point, we are still talking about frayed fiberglass sleeving and not inner conductors or other types of multi-conductor enclosed such as Rockbestos heat wire found as similar to extension cord in having a jacket covered multi-conductor round cable but it as type also being rated for the heat. Inspection of individual conductors when repairing the outer sleeve of normal fiberglass sleeved whips is very necessary before any such attempt at even temporary repair. If inner conductors are exposed such a repair will make such a thing even less safe especially given the conductive heat reflective coating on the sleeving which is normally conductive but not grounded..
Of inner conductors, there is different types of normal heat wire used beyond Teflon verses silicone based. Some have there own fiberglass weave over the individual conductors, others have a shiny abrasion resistant coating over the conductors. Both are serviceable in their temperature range. The Teflon/silicone type wire without the fiberglass sleeving over it does melt down at times especially near the lamp base in exposing conductors. The other type normally becomes brittle with the insulation falling off but there is at least the fiberglass still to some degree protecting the conductors. Much of personal choice, both have flaws. In extreme temperatures I add a further 1/8" to 3/16" fiberglass sleeve over the conductor near the lamp base no matter what the insulation type is. A further disadvantage of the fiberglass sleeved individual conductors is that when abraded, that fiberglass coating like with the overall sleeve will fray and look like hell. This often does not mean the conductor is in a substantial way less insulated electrically or unsafe if the silicone is still there, but it is often the case the inner silicone coating on the wire will be damaged necessitating replacement. In the case of individual conductors with fiberglass sleeving, some fiberglass electrical tape is very much a suitable replacement and repair for it’s protection given the silicone coating is not substantially damaged in exposing conductors. Teflon wire if slightly abraded can be repaired with Teflon high temperature electrical tape in the same way. Both tapes don’t readily peel up especially within a protective #0 fiberglass over-sleeve and would be a suitable repair within the cord. We are talking about the outer coating of either all fixture wires here or individual conductors in not exposing a live conductor to the touch otherwise.
On things such as Mole lights (audience blinders) where the fiberglass sleeving is constantly abused, I have started to switch the above fiberglass sleeving normally coming with such fixtures over to conductors with vinyl and more expensive but better yet silicone coated fiberglass sleeving over the conductors. Such a outer coating of the whip in abuse situations very much is more resistant to abrasion and abuse. Such a coated sleeving on Lekos is a budget verses time repairing problem but once and if such coated sleeving becomes in larger demand and distribution, such a replacement to the stock #0 black fiberglass sleeving to this point is a very acceptable replacement in never having your cord sleeving look like hell again. One might expect in the future far from now that such coated fiberglass sleeving will become the norm in never having to deal with such frayed outer covering protection over lamp cords.
This is my opinion on a suitable repair to the inner conductors of a lamp cord given SF-2 type heat wire with fiberglass sleeving as normally found on stage lighting fixture. Especially as a suitable repair to the outer jacket of a conductor, the use of said heat tape given it’s only the outer coating on a conductor that is damaged. Much less the Plyobond option in fixing small holes that later open up to become larger holes. I would not use it to repair such a whip when inner conductors are exposed, just when the outer jacket of the conductor shows a little bit of damage and or if the outer sleeving shows a hole but it’s not extensive enough to necessitate replacement yet. Electrical tape both is not rated for the temperature and looks like hell, the fiberglass electrical tape on fiberglass sleeving will also look like hell especially since it’s white but it will certainly be temperature rated.
A fresh spool of sleeving to replace lamp cords with is no doubt that start of the solution because on average the inner conductors will be fine. In any case, this is all stuff that needs proper supivision in doing and choosing what is and is not safe to just repair in a specific technique. Given we are the source for this recommendation, more information is still necessary before a proper action should be taken amongst them don't touch the fixures, send them in for repair. Part of doing business, your school either puts up the money for someone qualified to repair such equipment or by rights they are best suited in paying someone else to maintain said equipment. Soo many details of gear students should not without supervision do the repairs.