BS 5308, EN 50288 and PAS 5308
There is confusion in the marketplace for Control and Instrumentation cables, which is rooted in the preparation and issue of “BS EN 50288-7 – Multi-element metallic cables used in analogue and digital communication and control. Sectional specification for instrumentation and control cables.”
Due to the Rules of BSI/CENELEC, when this Standard was issued, it was deemed to cover the same types of cables as those in BS 5308 Parts 1 and 2, a conflicting Standard, and so BSI was obliged to withdraw these two standards.
BS5308 Parts 1 and 2 were withdrawn and superseded by EN 50288-7 in 2005.
It is of interest to note that the format of BS5308 Parts 1 and 2, which had been around since 1975, like most British Standards at this time, was prescriptive, whereas the format of BS EN 50288-7 was essentially performance-based. There are and always will be a number of variants to the old standard that could not be applied, but the market demands were apparent, so EN 50288-7 was all-encompassing.
Although covering similar cables, the BS Standards and the BS EN Standard were not identical, and perhaps the difference that presented the greatest problem to previous users of BS 5308 was the Voltage Rating, which, in the 1986 edition, had been increased to 300V rms to earth and 500V rms core to core. This, too, should be increased to 600/1000 for some installations where the ducting only offers one compartment.
It is, however, important to note that even with this increase in voltage rating, BS 5308 cables are still Control and Instrumentation cables, not Power cables.
As it clearly states in the Scope of both parts of BS 5308, “Instrumentation cables are not for connection to a low impedance source, e.g. a public mains electrical supply.”
The Foreword also states Part 1 of BS 5308 covers polyethylene-insulated cables used mainly by the petroleum industry. Part 2 covers PVC insulated cables used mainly by the chemical and petrochemical industries.
In response to used demand, in 2009, British Standards published PAS 5308 Part 1 and Part 2. PAS is a Publicly Available Specification which, although being an official document issued by BSI, is not to be regarded as a true British Standard.
Unfortunately, some people who do not understand the significance of the difference between a “Standard” and a “Specification” erroneously treat these Specifications as Standards. This was the other reason for the negative response to the 50288-7, as many of the petro-chem standards referred only to 5308. It is possible to reference to a withdrawn standard, although the materials are now out of date.
Timeline
- 1975 – BS 5308 Part 1 and Part 2 issued
- 1986 – BS 5308 Part 1 and Part 2 revised and updated
- 2005 – BS 5308 Part 1 and Part 2 withdrawn and superseded by BS EN 50288-7
- 2009 – PAS 5308 Part 1 and Part 2 issued
- 2024 – PAS 5308 Part 1 and Part 2 withdrawn
- 2024 – BS EN 502880-7:2005 is currently under review
Present Position
Currently both BS 5308 Parts 1 and Part 2 plus PAS 5308 Part 1 and Part 2 have been withdrawn by BSI without issuing a Standard to replace them, other than BS EN 50288-7.
This will leave some people with a problem and means that, if installing these types of cable, they will now have to complete a Deviation when signing off an installation.
