Cable supplier or electrical supply prices verses theater lighting suppliers are for the most part one in the same range and based on volume of their purchases and at times reflective of your purchases of their product. All about the discount factor. Often unless near a dealer of a sort in a major city such a thing won't be
stock thus won't be volume discount but its possible to be just as cheap. I normally buy 500' spools of it in all the
wire gauges and types
thru all the above suppliers and more to keep in
stock. McMaster Carr also sells heat
wire as a source - as with Grainger, not the cheapest but they got it when you need it. Your theater supplier will be more likely to
stock it than any place else at a reasonable price. Not all that common a
wire to use elsewhere in the wiring industry.
For starters, the initial question of what temperature range you are asking for is very important.
Consider three classes of heat
wire. 150c, 200c and 250c. That's celeious temperature. After that Silicone and Teflon heat
wire are the same for all intensive purposes in the temperature
rating and more dependant upon the mixture of those materials used for the cable for achieving a temperature
rating than what material is used. Both within that temp.
rating will react the same. Beyond this there is fiberglass sleeved and non-sleeved conductors that can both have the same temperature
rating and materials. (I prefer fiberglass coated in having an extra layer of protection.)
There is also multi
conductor heat
wire available tuch as Tempflex that's these days like a Euro-cable with the hot
neutral and
ground already in a silicone 200c temperature rated cable. Way back when there was also a better cable called Rockbestos that was much like a type SJ cable but as with the above both rated for 200c. (600v AWM #4418, Rockbestos 14/3 Supernat Heatzone 200̊C - good stuff but discontinued.) Than there is a fiberglass braided varish like coated three
conductor cable which is rated in the 250c range. Ainxter
www.anixter.com can get it special order but it's not cheap, nor is it flexible. There is other cable available beyond these but the above and below types would be the main types used in theater type lighting gear.
Most cable used on lighting fixtures will be Teflon or Silicone based 200c heat
wire that's either fiberglass coated or not. It is called type SF-2 and at 16ga has 24 strands of
wire to each
conductor. (There is also a type SFF-2 amongst other types out there so be careful with what you
purchase. SFF-2 is only rated for 150c.)
Cole
Wire & Cable
www.colewire.com catalog p.C4: "
Fixture Appliance
Wire Type SF-2, 600 Volt, 200C, Stranded tinned copper, silicone insulated, Impregnated glass braided
jacket, Stocked (or dipped but special order) in various colors.
CSA Type SEW-2." This is available from 18ga to 10ga in size. Cole is like many cable distributers, that's all they do and often cheaper buying direct but again based upon volume.
This SF-2 is the most common type of lighting
fixture wire both for temperature
rating and flexibility balance. IN certain fixtures I will uses type TGGT 250c
wire but while it is rated for more temperature it's less flexible in strands of
wire able to flex. Not the type of stuff that will last a lifetime being plugged in and moved about and for that reason it does not make a very good
fixture whip. Often I'll use something 200c for the
whip and 250c inside the
fixture itself - this especially inside an
audience blinder or studio
Fresnel where the conductors don't have to flex as much but will be near a lot of heat.
In the same respect, I will also use a type K/ FEP 150c
wire for the
ground. I want to know if my
fixture is overheating and the best way to know this is to use 150c
wire for the
ground - something that can be safely exposed and if seen to be melted you know you have a problem with the other conductors. This using the
ground in a lower temperature
rating than the other conductors will be more safe to use given your fixtures are inspected. Not less money, just the concept of having something that will indicate a problem. Kind of like a radiation tag on your lab
jacket. Not going to protect you, but it will indicate when you get too many rads.
Again, lots more types of heat
wire out there on the market, as with fiberglass and other materials used for the sleeving. That and vinal and silicone coated fiberglass sleeving, grades of fiberglass sleeving and thermoplastic sleeving to over
cover your conductors. Gets involved with lots of things to playtest. I'm a big fan of vinyl coated fiberglass sleeving for many things such as a
fixture whip on an
audience blinder or
cyc light for instance. For some reason gear that has three individual whips braided together seem to take more abuse than other equipment with a single
whip thus more reinforcement is needed. McMaster Carr has a really good selection of different types of sleeving. As the temperature
rating goes up on the fiberglass sleeving, so does it's abrasion resistance. This in addition to stuff like Kevlar reinforced
etc types of sleeving.