[From：来自网络] [Author：admin] [Date：11-09-27] [Hit：]
The instrumentation cables voltage rating for offshore project has a lot of variety. Some of the project specify the voltage rating must be 300V/500V as per BS 5308, another one specified 250V/450V without referring to any standard and code (it serve for fire & gas detector). There is also 600V/1000V voltage rating in some project to serve the control and 220-230 VAC source. So which one we shall use in the offshore platform oil & gas project?
First of all, the end user (Company or Operator) of the oil & gas project have their own preference regarding the voltage rating for instrumentation cables. Usually it based on their experience in the past project that has been proven in so many offshore platforms that they ever built. For sure they have a reason to choose certain voltage rating and not choose another one. But sometimes, when we questioned to them why they use or prefer to use certain rating and not use another one, their answers are it’s a general practice in all our facilities.
The international standards & codes are always changes. Therefore as instrument engineer we shall always update our knowledge regarding these changes. Some standards & codes are changes due to new proven practice or due to more stringent requirements. The standard & code for instrumentation cables also does like this. They were changed and updated year by year.
For example, the BS 5308 standard has been superseded by BS 50228 for a long time ago. But until now, the instrument cables for offshore platform that refer to this standard and code are still widely used and produced. Why it’s still used when the standard it self has been superseded? What’s behind of the voltage rating for the instrumentation cables made as per BS, IEC or any standards & codes?
To get clear description regarding the voltage rating of instrumentation cables manufactured as per BS, IEC, or any standards & codes, the following comparison of BS and IEC cables are given.
Standards Voltage Grade Insulation (Pol