Continuous or discontinuous instrument cable entry
Thread Content
HG/T 20512-2014 Design Specification for Instrument Piping and Wiring>, in this specification, 8.1.13, what do "continuous" and "discontinuous" mean? Please guide me, thank you.
One uses a gland and the other uses an explosion-proof pipe.
For non-armored cables (intrinsically safe), explosion-proof flexible pipes must be used, right?
No, intrinsically safe cable capacitance and inductance are low
Doesn’t that conflict with the norm?
There is no conflict. This type of gland is suitable for discontinuous pipes. If explosion-proof flexible pipe is used, it will be continuous. There is no conflict.
My understanding is that if your intrinsically safe cable has low inductance and capacitance, just use a gland. Because even if the cable protective layer is damaged and short-circuited, there will be no sparks, so it is fine if the cable is exposed. If the power cable is a power cable, it is recommended to use explosion-proof flexible pipe.
Whether intrinsically safe or flameproof, it can be continuous or discontinuous. Continuous refers to continuous protection. From the instrument, add the gland + flexible pipe + through pipe/trough box laying. Non-continuous means that the meter comes out and is installed with a gland + through pipe/trough box.
The flexible pipe also has glands on it.
Floor 8 is right. Discontinuity can better prevent water in the wiring pipe from flowing into the instrument junction box.
Thank you for your replies. Should explosion-proof flexible tubes be used for non-armored control cables?