Replacing asbestos wire

[Randy Stankey]

There is UV resistant wire sleeve available if that's critical, and Teflon jacketed wire is not bothered by UV.

Can Kynar jacketed wire be used in this application? (PVDF - Fluropolymer)

That's the stuff that's used on aircraft and jet engines and stuff like that. It's super resistant to heat, UV and most chemicals.
We use Kynar on many of the military orders where I work. The stuff is virtually bulletproof, as far as wire goes.

While I feel confident in recommending it on a general level, I don't know if wire is made with Kynar jacket at a large enough gauge to carry the current you need and I don't know whether the cost would be prohibitive.

The stuff we use is high-purity copper wire, plated with silver then jacketed with two layers of insulation, the outer layer being Kynar. We often use it in 28 AWG and I have seen it in sizes as big as 20 or 16 AWG but I've never seen it in sizes as big as 8 AWG.

[Gordon McLeod]

The big issue is finding wire that is flexible enough to to not put excessive load on carbon feed motors and drag down arc feed. Todate we have been allowed to just put a fiberglass sleeve over the short length that actual must flex and move but the rest of the lamphouse wireing must be removed

[Mark Gulbrandsen]

Can Kynar jacketed wire be used in this application? (PVDF - Fluropolymer)

That's the stuff that's used on aircraft and jet engines and stuff like that. It's super resistant to heat, UV and most chemicals.
We use Kynar on many of the military orders where I work. The stuff is virtually bulletproof, as far as wire goes.

While I feel confident in recommending it on a general level, I don't know if wire is made with Kynar jacket at a large enough gauge to carry the current you need and I don't know whether the cost would be prohibitive.

The stuff we use is high-purity copper wire, plated with silver then jacketed with two layers of insulation, the outer layer being Kynar. We often use it in 28 AWG and I have seen it in sizes as big as 20 or 16 AWG but I've never seen it in sizes as big as 8 AWG.

It's not as heat resistant as Teflon wire is.... Perhaps because it has a polymer in it

[Randy Stankey]

I'm going by memory so forgive me if I'm wrong but I thought that Kynar is able to withstand temperatures up to 150 C.

I'm sure that manual stripping can be a PITA. At work, they use machines to strip wire.
The are a little big bigger than a shoe box and are powered by shop air. You scan a barcode on the reel of wire you want to strip then the machine sets itself to the wire diameter and insulation type. You dial in the strip length then insert the wire. A rotary cylinder with a blade inside spins around and, "Ka-chunk!" You have a perfectly stripped wire.

Not cost effective for a field technician but indispensable for a worker who has to strip 1,000 wires during an 8-hour shift.

[Mark Gulbrandsen]

sorry mark but short lengths under 15 ft or so the voltage drop will not effect wire size as much as current load and direct current requires larger gage wire due to non collapsing current running through the wire, what is most important is conductor stranding allowing more surface area of the wire per watt running through it especially at lower dc voltages like arc lamps use, also it is still valid in the nec that min. wire gage to any projection lamp is #6 awg no matter how low the actual line current is. in AC wiring it is generally recommended to adjust wire size on lengths over 100ft as solid conductors have more voltage drop than stranded conductors. read up on the nec recommendations, also open wires will handle more current then encased wires no matter the run length. ie: in conduit or underground, etc.

Hence my comment about the 8 floors of buss bar at the Chicago Theater...

[Robert Sobin]

John, I have a few ORC model 2500 power supplies with lamp houses. In the pics attached they appear to have asbestos impregnated cotton strand wire as you described it. earlier. Am I correct in my assessment that the wire is basically harmless?

[John Eickhof]

that is 1970s vintage wire, it is gypsum impregnated and is just fine to use that wire is still available today.

[Robert Sobin]

Thanks John. Your insight saves me a lot of unneeded work.

[Paul Finn]

What is John Eikhof's remembrance of the high temperature cable insulation used in the Ashcraft Core-Lite lamps of the 1950s? Does it have possible asbestos issue problems?

Thank you, Paul Finn

[Paul Finn]

---

Sorry, should have spelled John Eickhof.

[John Eickhof]

Paul, I haven't seen a core light lamp in years, but I have an Ashcraft S-86 Super high (aka RCA Dynarc) from the late 50s and it has wiring resembling the same cotton/gypsum blend and is very flexible and does not appear to shed any material under flexing.Its about #2 awg

[Gordon McLeod]

CSA doesn't approve the use of a cotton gypsum blend or in fact any fabric based insulation on wire. I couldnt even find a company still listing it

[Mitchell Dvoskin]

How about the Kneisly L-500 Pup, is the 2 wires from the rectifier to the lamphouse asbestos or gypsum?

[John Eickhof]

if it was made after mid 1970s its most likely gypsum, CSA is the northern equiv to UL or Edison testing labs, they are private testing underwriters, the wires are addressed in the NEC, UL, and ETL, granted they may be obsolete now due to lack of demand or more modern replacements but in the states as long as used per mfg design specs and UL testing, the wires are acceptable per NEC Most arc lamps (both carbon and xenon short arc) made in USA were approved by UL, the problem with asbestos stems from the EPA and was primarily aimed at loose fiber asbestos content of mortars, plasters, steam pipe wrapping and other situations where use could cause exposure to loose fibers. It is also known the flammabilty of neoprene or rubber coated wire is higher than these older type wires, thus kevlar and fiberglass have come into use but are very rigid and not suitable for constant movement like an arc carriage. Asbestos cotton cable was in use through the mid 1980s and its use is addressed in article 530 and article 540 of the NEC.

[Mark Gulbrandsen]

It would be easy to find out what Strong is using now. They still produce at least two of the follow spots in LaVista, NE. So you could call them and ask, or just order a negative (Front cable, as the lamps were often mounted in reversed) lamp connection lead and see what it's labeled as. If no label call Strong back and ask for the MSDS sheet on the wire they sent you....