The armor provides mechanical protection against crushing forces. Armor also can serve as an Earth Continuity Conductor (ECC). There are different types of armors available: metallic or non-magnetic Alumimium, Steel wire/strip.But not for a single type can be used in all occasions.
When an electric current passes through a cable it produces a magnetic field (the higher the voltage the bigger the field). The magnetic field will induce an electric current in steel armor (eddy currents), which can cause overheating in AC systems. The non-magnetic aluminum armor prevents this from happening.
What type of armor is suitable for single core cable?
Non Magnetic Material’s armoring for 1Ph System: This is not so however for a single-core cable, where eddy-current heating would occur if a magnetic material was used for the armoring. The material has to be non magnetic for armoring as in this case of return current is not passing through the same cable. Hence it will not cancel the magnetic lines produced by current. These magnetic lines which are oscillating in case of A.C. systems will give rise to eddy currents in magnetic armoring and hence armoring will become hot, and this may lead to failure of the cable. Hence Single core cables for use on A.C systems are armored with single layer of nonmagnetic (Aluminum) material.
· Armoring is Mostly following Type
· STA – Steel tape armor, used in multi-core cables (non-magnetic),
· AWA – Aluminum wire armor, used in single-core cables (non-magnetic).
· Tinning or galvanizing is used for rust prevention. Phosphor bronze or tinned copper braid is also used when steel armor is not allowed.
· As strip construction is economical, the manufacture always provides steel strip armoring unless wire armoring is specified.
· As per IS: 1554 Round Wire armoring is provided in cable where calculated diameter under amour is upto13mm. Above this the amour is either steel wire or steel strip of size 4.00X0.80mm.
Zhenglan Cable Technology Co., Ltd can do steel tape armor, steel wire armor, aluminum wire armor. Welcome your inquiry.
Contact Person: Miss. Linda Yang
Tel: +86 16638166831