PTFE Wires, Cables & Sleeves

PTFE insulated equipment/ hookup wires are generally used for internal wiring of various electronic and electrical equipments and other electrical purposes. They are most suitable to use in equipments involving for high frequency signals. Uniformity of insulation thickness around the conductor and very low dielectric constant of PTFE enables the transmission of high frequency signals with minimized signal losses as compared to other wires resulting in high quality signal transmission. Wires are manufactured in conformance with JSS, mil-W, BSS specifications as desired. PTFE equipment wires are available in different working voltages:

Type ET for 250 Volts,

Type E for 600 Volts,

Type EE for 1000 V.

In signal and control applications, there are situations when multiple wiring connections need to be used. For the purpose a single cable having multiple no of cores is better suited. PTFE Insulated Multi-core cables find use in almost every type of electrical, electronic and engineering industry. PTFE insulated multi-core cables are required especially for high temperature and high frequency applications.

PTFE insulated multi-core cables are available with screen or without screen. Screening is required wherever there is need to protect the transmitting signals from external electric and electromagnetic noises. The cables are available in various twisted configurations such as bunched twisting, multiple pair twisting and multiple triads twisting. Cables up to 100 cores can be made upon customer's request.

Cables can be overall shielded or all the cores can be individually shielded or specific no of cores can be shielded and rest can be kept unshielded as required.

PTFE Insulated Multi-core cables are jacketed to give mechanical strength and binding to the cable. The jacket can be of PTFE or PVC or Rubber as required. An Armoring of SS or GI wire braid can be provided over the jacket to give extra strength and durability to the cable.

The size of the electronic and electrical equipment is decreasing day by day bringing in the need of wires of smaller size so that they can be accommodated in reduced space in the equipment. In high voltage applications if size of conductor is reduced the corona (ionized discharge) is produced. This corona attacks the insulation and greatly reduces the life of insulating material. Hence to avoid the damage of insulation the conductor size has to be kept big which in turn limits the miniaturization process of the equipment. High voltage corona resistant (HVCR) cables remove this problem.

These cables are made by insulating the conductor with specially made corona resistant (CR) PTFE tape. CR PTFE tape has increased resistance to corona discharge which helps in making high voltage cables in reduced sizes.

The HVCR cables are available for voltages as high as 22 KV AC or 50 KV DC both with screen and without screen. Screened HVCR cables are recommended where electrical circuit in proximity of HVCR cable needs to be protected from corona..

In the wiring of electronic equipments used for transmission of electronic signals, it is observed that the signals get disturbed by external electric and electromagnetic noises produced by equipment, motors etc in close proximity with the wire which results in poor transmitted signal quality.

This problem is tackled by shielding/screening the equipment with a metal wire braid or aluminum/mylar tape serv shield or both and then finally covering it with protective jacket. The Shield is grounded and this helps in keeping the signals inside the inner conductor to be protected from outside noises. Single core shielded wires are available in various sizes generally ranging from 0.5 Sq mm to 4.0 Sq mm and above.

Heat resistant high temperature (HR) cables are used as power cables in plants where there is high temperature environment and ordinary PVC cables can not be used such as near rotary kilns, furnaces, boilers etc. Due to the high temperature around the furnace, the electrical wiring of motors , control panels etc. near the furnace gets damaged very frequently, which compels the replacement of cables at periodic intervals leading to precious loss of productivity. This problem is greatly reduced by using High temperature PTFE insulated H.R. cables

H.R. Cables made by Tefkot Cable Company are made by using PTFE insulation which is a High Temperature insulating material having excellent electrical properties and is inert to almost all chemicals and it also does not age. These properties make it suitable to be used as power cable in industries such as steel, cement, fertilizer, chemical etc.

PTFE is known to be the best dielectric for RF (Radio frequency) coaxial cables. The essential function of coaxial cables is to transmit high frequency energy and signals with low loss, with reflection less matching and without Phase and Amplitude distortion.

The problem in high-energy transmission is the losses because of i) cable dielectric, ii) cable construction, iii) radiation, and iv) interference with adjoining circuits.
The coaxial cable construction has been invented to overcome these problems, in which signals and energy are contained within an enclosed space. It consists of a core conductor, surrounded by pure PTFE dielectric covered with a metal shield, and finally encased in an overall jacket. The shield provides the return path as well as the confinement for RF energy, and is generally grounded.

TECHNICAL PARAMETERS OF RG COAXIAL CABLES WITH PTFE DIELECTRIC.

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RG Cable	Characteristic Impedance	Core Conductor (mm)	Core Dia (mm)	Shield	Outer Dia (mm)	Continuous Working Voltage	Max Operating Frequency	Operating Temperature	Nominal Capacitance (pf/mtr)	Attenuation at 400 MHz DB/ 100m (Max)
196 A/U	50 Ohm	7 / 0.10 SPCW	0.863 PTFE	1SPC Braid	1.800 PTFE	750 VRMS	3 GHz	Cryogenic to 200 C	95	103
188 A/U	50 Ohm	7 / 0.17 SPCW	1.524 PTFE	1SPC Braid	2.490 PTFE	900 VRMS	3 GHz	Cryogenic to 200 C	95	65.6
187 A/U	75 Ohm	7 / 0.10 SPCW	1.600 PTFE	1SPC Braid	2.540 PTFE	900 VRMS	3 GHz	Cryogenic to 200 C	65.6	68.9
195 A/U	95 Ohm	7 / 0.10 SPCW	2.591 PTFE	1SPC Braid	3.580 PTFE	1100 VRMS	3 GHz	Cryogenic to 200 C	52.5	55.8
142 B/U	50 Ohm	1 / 1.00 SPCW	2.946 PTFE	2 SPC Braid	4.950 PTFE	1400 VRMS	12 GHz	Cryogenic to 200 C	93.5	29.5
141 A/U	50 Ohm	1 / 1.00 SPCW	2.946 PTFE	1SPC Braid	4.830 VFG-1	1400 VRMS	3 GHz	Cryogenic to 200 C	93.5	29.5
115 A/U	50 Ohm	7 / 0.71 SPC	6.350 PTFE	2SPC Braid	9.530 VFG-3	3700 VRMS	12 GHz	Cryogenic to 200 C	93.5	17.1

PTFE sleeves are made by tape wrapping and sintering process as per JSS and other specifications. PTFE sleeves/ tubings find there application in various sectors such as:-

Defence,space, aerospace, radars etc.

Electronic communication and controls equipments.

Insulation over electrical joints wherever connections are likely to be  heated.

To cover lead wires coming out of equipments.

In Switchgears.

To cover and protect hot joints in proximity with chemicals

PTFE sleeves are made available in various bore sizes ranging from 0.50 mm to 25.00 mm in different wall thicknesses. Common wall thicknesses are 0.25 mm, 0.30 mm, 0.40 mm and0.50 mm. PTFE sleeves are available in 11 solid colours and various combinations in bi-colour and tri-colour as per requirement.

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S.No.	Nominal ID (mm)	Nominal wall thickness (mm)	Over all dia. (mm).
1	0.5	0.25	1
2	0.75	0.25	1.25
3	1	0.3	1.6
4	1.5	0.3	2.1
5	1.5	0.4	2.3
6	2	0.3	2.6
7	2	0.4	2.8
8	2.5	0.4	3.3
9	3	0.4	3.8
10	3.5	0.5	4.5
11	4	0.5	5
12	5	0.5	6
13	6	0.5	7
14	7	0.5	8
15	8	0.5	9
16	9	0.5	10
17	10	0.5	11
18	12	1	14

RTD cables manufactured by Tefkot Cable Company are used as connecting lead wire between RTD sensor and temperature indicator device. RTD Cables are made in 2 core, 3 core, 4 core and 6 core configurations, 3 cores being the most commonly used configuration.

CONSTRUCTION: RTD Cables are made in three common constructions for making them suitable for different situations. These are PTFE/PTFE = This is the most common construction. In this the cores are insulated with PTFE and then cores are twisted and jacketed with PTFE. PTFE/Fg = In this construction cores are of PTFE and jacket is of Fiber glass braid. This is used when RTD cable has to be installed in high temperature environment.
PTFE/SPC/PTFE = In this construction a SPC wire braid shield is provided between twisted cores and jacket. This type of Cable is used where higher accuracy is required. The current and voltage signals in RTD Cables are of very small magnitude and can get affected by external electromagnetic noises produced by external devises such as motors, electronic equipments etc near the cable. The SPC Shield is grounded from one end and this protects the signals in the cable from these external noises.

In all these configurations, an additional SS wire braid Armoring can be provided to increase the mechanical toughness of the cable.

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S.No.	SIZE (AWG)	Conductor Dia (mm)	Conductor Resiscnce (OHM/Km) max at 20degC	NOMINAL DIA OF FINISHED CABLE (mm)
				PTFE/PTFE				PTFE/Fg				PTFE/SPC/PTFE
				2 CORE	3 CORE	4 CORE	6 CORE	2 CORE	3 CORE	4 CORE	6 CORE	2 CORE	3 CORE	4 CORE	6 CORE
1	28/7/36 SPC ET	0.39	210.5	1.69	1.95	2.15	2.5	1.6	1.85	2.1	2.4	2.09	2.35	2.55	2.9
2	26/7/34 SPC ET	0.48	133.7	1.85	2.1	2.35	2.8	1.75	2	2.3	2.7	2.25	2.5	2.75	3.2
3	24/7/32 SPC ET	0.6	83.2	2.06	2.35	2.65	3.13	1.96	2.25	2.6	3.03	2.46	2.75	3.05	3.53
4	22/19/34 SPC ET	0.8	49.8	2.42	2.77	3.15	3.71	2.32	2.67	3.1	3.61	2.82	3.17	3.55	4.11

Conductor sizes shown in the table are the generally used common sizes. RTD cables can be made in other sizes also as per requirement. When using long cables, it is necessary to check that the measuring equipment is capable of handling the resistance of the cables. Most equipment can cope with up to 100 ohms per core. For better accuracy in measurement, longer the cable length being used, larger should be the area of the conductor so that the resistance of the lead wire is minimal.