Cable design and selection
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The newly installed set costs around 2,000 points and is located at a distance of 400 meters; the installations are relatively concentrated. Is it better to use multi-core cables with junction boxes or separate two-core cables? I hope Haiyou can give some suggestions
The answer to this question should be determined based on the company’s* practices. If there are existing* practices that have become established over time, those practices should be followed. In the absence of such a *standard practice, the two options are analyzed as follows: 1. Use direct-pull cables. The advantage is that it reduces the number of connection points in the process, facilitating fault analysis during maintenance ； The disadvantages are the heavy workload involved in laying cables, slow construction progress, and generally higher costs. 2. Adopt the main cable + junction box + branch cable configuration. The advantages are: it facilitates construction organization, saves construction time, and results in a slight cost reduction – though not much; this depends on the conditions set by the tendering authority. Once the external conduit system is ready, the main cables can be laid first, while the branch cables can be installed gradually based on the locations identified during surveys ； The downside is an additional joint location, which increases the number of potential failure points that need to be taken into consideration during maintenance, but the impact is minimal. Personal opinion, for reference only.
Both options are available on site currently; the design institute recommends adopting the main cable + junction box + branch cable approach, as it facilitates construction organization and saves costs. The instrumentation crew recommends using straight pull cables. Can’t decide right now
These are two options that carry a certain degree of inevitability; both the instrument workshop and the design institute have proposed them based on their own usual practices. In fact, if the schedule is not tight, adopting the suggestion to use instruments is also an option; after all, there are many tasks within one’s own company that need to be completed through collaboration.
The timeline is not tight; things are currently at an impasse: L
This post was last edited by glooom on 2018-10-24 at 17:39. The main cable + junction box + branch cable setup shows its advantages when changes need to be made later; once the cables are installed, making additional connections becomes very troublesome. I have worked in design as well as in construction management. From a design perspective, I prefer to have the cables run directly to the junction boxes – there’s no need to draw diagrams showing those connections or to create boxes for them; it’s also easier to prepare cable schedules. However, from a practical construction standpoint, this approach is not recommended
Trouble is trouble; but trouble is good. It’s more troublesome; that’s how you can earn some overtime pay. Optimizing everything to the extreme, with endless redundancy, will make it easy for you to lose your job. Do you understand unemployment?
Personal opinion: It’s better to place them separately. Single wiring is a point-to-point connection, from the instrument to the control room; it makes it easy to locate faults when they occur, and it does not affect the proper operation of other instruments ； Secondly, if a multi-core cable is damaged in the middle, even though there are markings on the cable, it is necessary to stop all instruments from operating during repairs, which affects normal production ； If the drawings for the third multi-core cable are not clearly labeled or have been lost over time, it becomes extremely difficult to find them.