Intrinsic safety system issues

1. The materials listed in the installation manual are generally purchased by oneself, but the special materials needed for installing instruments, such as clamps, come pre-installed with the product; however, aside from the clamps, almost everything else needs to be bought separately. 2. The cables that go from the safety barrier into the site… I haven’t heard that they need to be intrinsically safe, as I’ve never even heard of such things as intrinsically safe cables. However, the cables should be flame-retardant, and the instrument cables must be shielded. 3. Intrinsic safety instruments are a specialized type of instrument, primarily related to explosion protection. In intrinsically safe instruments, both the circuitry and components are safe, as the energy level generated upon arcing is not sufficient to reach the initial energy required for detonation. In addition, there is also the explosion-proof type, in which the enclosure is sealed so that any sparks inside have no effect on the outside. What is an intrinsically safe system... Why do I feel so ignorant for not having heard of it? Is InSafe now available as a system? What’s the use? Systems like this either need to be in a secure area or equipped with an explosion-proof enclosure; I’ve never heard of intrinsically safe versions – how much would that cost?……

1. When selecting instruments, by communicating with the manufacturer, one can learn about the installation methods for those instruments as well as the scope of supply provided by the instrument manufacturer. Most of the installation materials listed in the installation manual are not provided by the instrument manufacturers; it depends on the contracting method and agreements for the project as to who will purchase them. 2. In intrinsically safe circuits, intrinsically safe cables must be used; their insulation is usually blue, including the cable trays that lead into the cabinet. 3. Intrinsic safety instruments are a type of instrument that possesses intrinsic safety explosion-proof certification. Not all instruments can be used in intrinsically safe circuits. Intrinsic safety is a type of explosion protection that is achieved by limiting the energy in the circuit, as well as the capacitance and inductance. It requires an intrinsically safe barrier or isolator, intrinsically safe cables, and intrinsically safe instruments to form a complete circuit.

It can only be said that the original poster hasn’t even started yet. The information downstairs is also misleading. An intrinsically safe circuit does not necessarily use an intrinsically safe cable, and an intrinsically safe cable is not necessarily intrinsically safe.

I remember that according to the specifications, only an intrinsically safe instrument, an intrinsically safe cable, and a barrier can together constitute an intrinsically safe system. Intrinsic safety cables are generally blue in color, and their model numbers include the letter “ia” in addition to those of regular cables. If the design calls for this type of cable, then use it, so as not to be held accountable if problems arise in the future.

1. The \"Installation Manual\" referred to by the poster is likely HG/T 28518; it usually specifies a scope of application, and \"I\" generally refers to the instrumentation field. “\"P\" is generally provided by the piping specialty, but the instrumentation specialty needs to create the necessary conditions for the piping specialty. 2. If the field instruments are located in an explosion-proof area and are intrinsically safe instruments, then the cables that connect these instruments to the safety barrier must also be intrinsically safe cables. Such cables are usually sky blue in color, making them easily recognizable. In this way, intrinsically safe instruments, intrinsically safe cables, safety barriers, etc. can form an intrinsically safe circuit. None of them can be missing. If the field instruments are not intrinsically safe, then it doesn’t matter whether to use intrinsically safe cables or not. Because it is no longer considered a intrinsically safe circuit. 3. Intrinsic safety instruments are a separate category of instruments, and they are generally more expensive than ordinary instruments.

Apologies, the number for the aforementioned \"Installation Manual\" should be HG/T 21581; please accept this correction.

1. The so-called intrinsically safe cable is the proper term for “a cable that meets intrinsically safe parameters”. 2. The safety barrier manual specifies the maximum allowable inductance and capacitance values for external components (the parameters vary for IIB/IIC types); the inductance and capacitance of the cable plus transmitter must not exceed these values, otherwise it is considered a non-compliant \"intrinsically safe explosion-proof system\". 3. Inductors and capacitors with PVC insulation have relatively large values; the limit is exceeded around 200 meters ； The insulation made of polyolefins is relatively small, so running 600-700 meters poses no problem. 4. Therefore, the “intrinsically safe cables” available on the market are basically of the latter type, and the blue outer coating is used to identify the intrinsically safe circuit, serving as a reminder that maintenance can be carried out while the circuit is still energized. To give an extreme example, I used a regular computer cable (with black insulation) in place of an »intrinsically safe cable« in the intrinsically safe circuit. The cable was relatively short, and calculations showed that it met the required specifications. A label on the gauge indicating »intrinsically safe circuit« was present, allowing for maintenance while the circuit was still powered. It’s just that manufacturers are unlikely to provide the specifications for black-insulated cables, making verification and calculation difficult. Twisted pairs with polyolefin insulation can generally meet intrinsically safe parameters, and the manufacturing threshold for such intrinsically safe cables is not high. @jiaguoyun @Big Horse with Big Bow

It is recommended that the original poster first understand what an intrinsically safe circuit is and its function. Don’t rigidly follow the standards.