NEW EUROPEAN STANDARD EN50143 FOR HIGH VOLTAGE CABLES USED IN NEON INSTALLATIONS

As a Manufacturer of components for cold cathode lamps, Tecnolux believes that through specifications and instructions for reliable and safe neon sign installations is critical. Carelessness and misinformation create hazardous conditions for both people and buildings in which signs are gl installed. The installation and use of high tension requires diligence, skill and professionalism.

The purpose of new European standard EN50107 is to set forth requirements for safer neon installations. Along with EN50107, new specifications in EN50143 are soon to be published concerning the use of high tension cables.

The new guidelines in EN50143 have been developed from a list of commonly used cables throughout Europe. Cables are listed according to mechanical and electrical tests that provide a minimum level of safety and quality.

The attached tables describe 9 types of cable that comply with EN50143. The cables are labelled with the letters A, B, C, D, E, F, G and K. The tables also indicate rated voltage ( Uo / U), external diameter (mm), maximum temperature rating (°C), and the corss section size of the copper conductor (mm²).

Rated voltage is expressed by the combination of the values Uo/U : whereas Uo is the r.m.s value between any insulated conductor and "earth" and U is the r.m.s value between any two phases of a system of single core cable.

Cable type A, commonly used in Great Britain, but relatively unknown elsewhere, is composed of a single copper conductor with a robber compound insulation and lead sheath with a thickness of l.lmm.

Cable В, С, and D have silicone insulation.

• Types С and D are equipped with an additional sheath and D contains an added copper braided screen between the insulation and the external sheath.

• Each of types С and D is divided into two styles according to the kind of sheathing.

Types C₁ and D₁ are covered with a standard PVC sheath, while С₂ and D₂ are covered with a non-

alogen sheath (i.e. no emission of toxic or injurious gases during combustion).

Cables E, F, and G are insulated with PVC robber.

• In type E, a zinc tape of 0.25mm thickness is applied around the insulating robber and a conductor with a cross section of 1.5mm² is added for a continuous link to earth. The entire cable is then with a PVC sheath.

• Types F and G contain no metallic screen. The difference between these two cables is that type F is covered with an additional PVC sheath whereas G is not. The sheath compound in type F is different than the insulating material even if the colour is not the same (yellow).

Cables H and К have a composite insulation of polyethylene and PVC. The difference between them is the rated voltage. Type К is the only cable designed for a working voltage of 2.5/5Kv instead of 5/10Kv.

To determine the correct cable type to use in a particular application, one must utilize the following table from EN50107 (table 1, section 14. 4).

 

	Cables may be used:
Type of cable	with protective enclosures	in all situations other than in or under surface	in or under surfaces
A	X	X	X
B	X	-	-
C	X	X	-
D	X	X	X
E	X	X	X
F	X	X	-
G	X	-	-
H	X	X	-
K	X	X	-

Note 1: The cable insulation may be allowed to come into contact with earthed metal work or other materials within an enclosure.

Note 2: Examples of protective enclosures include sign boxes, enclosed letters, cable ducting, stell tubes and flexible armoured conduit.