Standards – What they mean?


Wiring Regulations BS7671:2008 AMD 3 (2015)

The principle changes to the Wiring Regulations BS7671:2008 that effect concealed cables are:

  1. The relevant regulation clause numbering has changed to 522.6.201 – 522.6.204.

Implemented in July 2008 the 17th Edition of the Wiring Regulations included many changes from the 16th Edition, one of the most significant then was the requirement to use RCD’s, RCBO’s and/or shielded cables to BS8436, in thin walls or partitions of less than 50mm depth or with internal construction using metallic components, these are still options called up in Amendment 3:2015 of BS7671:2008.

So cables that meet BS 8436:2011 are a satisfactory solution to the relevant Regulations for these applications.

 

BS8436:2011:

BS 8436 was released in August 2004, knowledge of the BS 8436 standard has slowly filtered into the fixed electrical wiring sector, it did feature in the 16th Edition of the Wiring regulations but now has a more prominent role as a safety cable for concealed cables in the 17th Edition and still remains as a key cable option for this application.

Scope of the standard is:

  • • Voltage rating: 300/500v
  • • Range: 1.0mm to 4.0mm2, 2c 3c & 4c plus earth.

Three principle performance criteria called up in BS 8436:2011 are:

Nail Test:  A 0.9kg a weight dropped from a height of 400mm driving a steel nail through the cable, the cable is deemed to have passed if it operates up to a 32A Type B MCB in six consecutive valid strikes..
Impact test: A 0.5kg chisel-edged weight is dropped from a height of 250mm and the cable shall maintain its electrical integrity. The same is done with a radiused weight. The test is carried out at 20 Deg C.
Water immersion test: A 20m sample of cable is immersed into water at 20 Deg C for 24 hours. The cable’s electrical integrity is tested following this.

IS273:

An existing Irish standard that was modified to include cable failing safe under nail penetration, this standard was based on BS8436, but has a number of important differences: 

Scope of the standard is:

• Voltage rating: 600/1000v

• Range: 1.0mm to 6.0mm, 2c 3c & 4c plus earth

The principle performance criteria called up in IS 273 are basically the same as used in BS8436.